The Missing Link in T-cell activation using a Vaccine, "The Danger Signal" may be due to an enzyme called IDO

The Missing Link in T-cell activation using a Vaccine, "The Danger Signal" may be due to an enzyme called IDO

As I research why some patients respond to therapies i.e. vaccination and other immunotherapy and others don’t, I ask WHY? In my quest to get the answer or answers, I came across a paper called “Marked Differences in Human Melanoma Antigen-Specific T Cell Responsiveness after Vaccination Using a Functional Microarray”.

Daniel S. Chen1,2#, Yoav Soen3#, Tor B. Stuge4, Peter P. Lee4, Jeffrey S. Weber5, Patrick O. Brown2,3, Mark M. Davis2,6* 1 Department of Internal Medicine/Division of Oncology, Stanford University, Stanford, California, United States of America, 2 Howard Hughes Medical Institute, Stanford University, Stanford, California, United States of America, 3 Department of Biochemistry, Stanford University, Stanford, California, United States of America, 4 Department of Medicine, Stanford University, Stanford, California, United States of America, 5 Norris Cancer Center, University of Southern California, Los Angeles, California, United States of America, 6 Department of Microbiology and Immunology, Stanford University, Stanford, California, United States of America

This is what I was looking for! It may hold the answer or could possibly point me in the right direction. In the paper I came across a diagram that peaked my interest. It was a comparison between responders and non-responders.

We concluded from these studies that IL-1 and perhaps IL-6 play a critical role in the differentiation and expansion of Th17 cells. Yoshihiro Miyahara et al

 

IL-6 controls Th17 immunity by inhibiting the conversion of naive CD4⁺ T cells into Foxp3⁺ regulatory T cells.

Using in vitro and in vivo approaches, we determined that under neutral conditions, simultaneous activation of Tregs and naive CD4⁺ conventional T cells in the presence of APCs resulted in conversion of Tregs into IL-17–producing cells, and endogenous IL-1β was mandatory in this process according to Vassiliki A. Boussiotis et al. “IL-1β–Mediated Signals Preferentially Drive Conversion of Regulatory T Cells but Not Conventional T Cells into IL-17–Producing Cells”

IL-6 protects CD4 T cells from cell death but also inhibits the suppressive effect of T regs.

“Thus, the addition of IL-6 to the tumor microenvironment skews the balance toward Th17 cells in a murine model of pancreatic cancer. The delayed tumor growth and improved survival suggests that induction of Th17 in the tumor microenvironment produces an antitumor effect.” David C. Linehan  et al

They were looking at the cytokines secreted after the vaccine was given. When I saw what the cytokines were, I knew I was on the right track. These cytokines help in the differentiation of the CD4+ T-cells. What a find!!

Naïve CD4 T cells in the presence of   TGF-b and IL-2 and others differentiate into Tregs.

TGF-b accelerates the CTLA-4 expression by stimulated CD4+ CD25- T-cells

TGF-b requires CTLA-4 early after T-cell activation to induce FoxP expression generating CD4+ CD25+ Treg  Regulatory cells.

The Th-17 cells produce IL-17. .IL-17 induces the production of many other cytokines (such as IL-6, G-CSF, GM-CSF, IL-1β, TGF-β, TNF-α)

 

So what was the non-responder missing, IL-6.  With the missing IL-6, they weren’t able to produce Th-17 that secreted IL-17.

While TGF-β is a critical differentiation factor for Treg cells, IL6 completely inhibits the generation of Treg cells induced by TGF-β. Instead, IL6 and TGF-β together induce the differentiation of pathogenic Th17 cells. With IL-6 missing in the microenvironment, Treg Cells flourish.

If the CD4 + T cells differentiate into TH2 cells that produce IL-4, the other cells inhibited to produce IL-6. IL-4 was found to inhibit TNF-α and IL-1β by activated monocytes almost 100 %. The Secretion of IL-6 was decreased by approximately 80 % in the presences of IL-4 Cytokine. TE Velde et al 1990

 They were missing “The Danger Signal”.

Friendly inflammation “The Danger Signal”

Most of the time you have no notion of the microbial life-and-death struggle being waged within your body. At other times, though, you are acutely aware of the exact location of the battleground, thanks to the unmistakable signs of inflammation — heat, pain, redness, and swelling. Inflammation, the buildup of fluid and cells at the point of infection/cancer, is put into motion by cytokines — proteins that are released into the blood by the innate immune system when it encounters germs. Cytokines function like police dispatchers. They signal there's a problem, which activates the immune system's highway patrol force: the circulating lymphocytes of the adaptive immune system. These lymphocytes cruise the highways of the blood vessels and lymphatic system. In response to the chemical signal from the cytokines, increased blood flow rushes these circulating cells to the trouble spot.

 “The CD8+ T-cell-mediated Immune Response to Eradicate the Tumors”

 “Three major events must occur to induce CD8+ T cell–mediated, tumor-protective immunity against syngeneic melanoma. First, the T-cell receptor must be triggered by a (or multiple) self antigen–derived peptide MHC class I complex . Therefore, this event depends entirely on appropriate antigen presentation, which is most efficiently provided by mature dendritic cells. Peripherally tolerant or “ignorant” self-reactive T-cell clones, once properly activated, may serve as tumor-specific effector T cells .Second, simultaneously with T-cell receptor triggering, a distinct second costimulatory signal must be delivered, mediated by IL-2, B7-1, or B7-2, which engage IL-2 receptors and CD28 on the surface of the T cell, respectively. A source of these cofactors for effective CD8+ T-cell stimulation can be provided by CD4+ T cells that release critical amounts of IL-2, or by mature dendritic cells that display an increased level of B7-1/B7-2 costimulatory molecules on their cell surfaces. Third, inflammatory cytokines, including IL-1, IL-6, IL-12, IL-17 and IFN-γ provide a third signal that acts directly on T cells, referred to as the “danger signal”. This signal was found to optimally activate TH1 differentiation and lead to clonal expansion of T cells.

 

 

 

The responder was able to produce inflammatory cytokines, including IL-1, IL-6, IL-12, IL-17 and IFN-γ provides a third signal that acts directly on T cells, referred to as the “danger signal”. This signal was found to optimally activate TH1 differentiation and lead to clonal expansion of T cells and invoke a robust immune response to the Melanoma Cancer.

 

 

Conclusion:  Based on my observation, the cytokine that ties this “Danger Signal” to the immune system is IL-6.

• IL-6 protects CD4 T cells from cell death but also inhibits the suppressive effect of Tregs.
• IL-6 controls Th17 immunity by inhibiting the conversion of naive CD4⁺ T cells into Foxp3⁺ regulatory T cells.

So what is causing the lack of IL-6 in the non-responders? The IDO enzyme. This enzyme catalyzes the degradation of the essential amino acid L-tryptophan to N-formylkynurenine.

IDO enzyme degrades tryptophan and through the GCN2 kinase pathway inhibits the transcription of IL-6. Without the transcription of IL-6, the IL-6 cytokine cannot be produced leading to the T-cell differentialtion toward the T Regulatory cell instead of the TH17 phenotype.

My guess is the tumor induced enzyme called IDO may the Missing Link to intiating an immune response.IDO produced by Tumor cells significantly inhibited interleukin (IL-2) expression and proliferative response in T-cells and increased apoptosis (death) of T-cells. Tryptophan depletion is known to halt cell cycle progression by triggering the antiproliferative GCN2 pathway in lymphocytes.

Also, IDO is upregulated in antigen-presenting dendritic cells (DC) by autocrine IFN-γ released as a result of T_reg cell–induced CTLA-4/B7-dependent cell-cell signaling.

It is well established that IDO expression by APCs or tumors can inhibit immune responses.

Tryptophan depletion by IDO-expressing tumors is a common mechanism of immune evasion inducing regulatory T cells and inhibiting effector T cells.

So adding IDO inhibitor to a combinatorial therapy like Yervoy for melanoma cancer should see a synergist response.

 

 

 

 

Bristol Myer Squibb and Incyte Corporation are following this Science along
Newlink.

“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.” ~Charles Darwin~

Take Care,

Jimmy B

Immunotherapy.. The Magic Bullet.. The Breakthrough Therapy.. the Paradigm Shift.. The Future

I wrote about this as the "Magic bullet" back in 2009.Great insight in where immunotherapy is heading in the future.



When you combine anti-CD47 therapy with checkpoint therapy (anti-PD1 and or anti-CTLA4/Yervoy), you involve the innate and the adoptive immune system to eradicate cancer (Melanoma)
 I would like to see combinatorial therapy with checkpoint inhibitors like yervoy/anti-CTLA-4 & anti-PD-1along with anti-CD47 to eliminate the "don't eat me" signal, so the macrophages can get involved with the tumor elimination.

http://www.youtube.com/watch?v=XGeqAEr1RnE&feature=share


“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.” ~Charles Darwin~

Take Care,

Jimmy B

Is this the smoking gun to Melanoma and the reoccurrence the plasticity of the Macrophages?..Jim Breitfeller

Is this the smoking gun to Melanoma and the reoccurrence the plasticity of the Macrophages? The (TAM) Tumor Associated Macrophage or more precisely M2-Like Phenotype.
In my search for answers, I have been focusing in on how the tumor escapes detection by the immune system. We need to know what is going on in vivo during the different stages of melanoma.

The tumor mass is undoubtedly a multifaceted show, where different cell types, including neoplastic cells, fibroblasts, endothelial, and immune-competent cells, interact with one another continuously. Macrophages represent up to 50% of the tumor mass, and they certainly operate as fundamental actors. Macrophages constitute an extremely heterogeneous population; they originate from blood monocytes, which differentiate into distinct macrophage types, schematically identified as M1 (or classically activated) and M2 (or alternatively activated).

It is now generally accepted that TAMs have an M2 phenotype and show mostly pro-tumoral functions, promoting tumor cell survival, proliferation, and dissemination. High levels of TAM are often, although not always, correlated with a bad prognosis, and recent studies have also highlighted a link between their abundance and the process of metastasis.

In a recent research paper “Immunotype and Immunohistologic Characteristics of Tumor Infiltrating Immune Cells are Associated with Clinical Outcome in Metastatic Melanoma”1 et al Slingluff 2012, it breaks down the Immunohistologic Characteristics into three distinct immunotypes:

A) No infiltration of immune cells in the tumor’s microenvironment.

B) Infiltrating Immune cells only in close proximity to the tumor’s vascular system

C) Diffuse immune cell infiltrates throughout a metastatic tumor and its microenvironment.

Immunohistologic Characteristics of Tumor Infiltrating Immune Cells


Overall, the most predominant immune cells were T cells (53%), followed by the B cell lineage cells (33%), and then by macrophages (13%), with NK and mature dendritic cells only hardly present.

With the setting of the tumor’s microenvironment evaluated, we will focus the low survival immunotype A patients.

How can we improve the overall survival and the immune response to Melanoma? We need to push the differentiation of the macrophages towards the M1 phenotype.

Macrophages are important tumor-infiltrating cells and play pivotal roles in tumor growth and metastasis. Macrophages participate in immune responses to tumors in a polarized manner: classic M1 macrophages produce interleukin (IL) 12 to promote tumoricidal responses, whereas M2 macrophages and M2-Like produce IL10 and help tumor progression. The mechanisms governing macrophage polarization are unclear but in 1990 it was discovered treatment of M2 macrophages with GM-CSF or IFN-gamma led to production of M1 phenotypic markers upon LPS stimulation. It also has been seen that if you block the IL-10 receptor with an antibody along with LPS (TLR4 agonist) stimulation or CpG (TLR9 agonist) stimulation you shift the Macrophage plasticity towards the M1 phenotype.

So what causes the high Macrophage (M2) to migrate towards the Tumor and its microenvironment? Does the tumor somehow recruit these (TAMs) Tumor Associated Macrophages? What are the characteristics of the M2 phenotype?

Hallmarks of M2 macrophages are IL-10high IL-12low IL-1rahigh IL-1 decoyRhigh production, CCL17 and CCL22 secretion, high expression of mannose, scavenger and galactose-type receptors, poor antigen-presenting capability and wound-healing promotion.

CCL17 and CCL22 chemokines within tumor microenvironment are related to infiltration of regulatory T cells in Macrophage 2 in melanoma. Early Detection of Tumor Cells by Innate Immune Cells leads to Treg Recruitment through CCL22 Production by Tumor Cells and Tumor Assocated Marophages (TAMs). It has been suggested that at early times during tumorigenesis, the detection of tumor cells by innate effectors (monocytes and NK cells) imposes a selection for CCL22 secretion that recruits Treg to evade this early antitumor immune response. The activated T-cells upregulate the CTLA-4 and PD-1. PD-1 ligation induces IL-10 production by monocytes, which together with PD-1 inhibits CD4+ T cell responses/activation. This is way for the immune system to use a checkpoint so that immune response does not lead to an autoimmune response. These receptors keeps the immune system in check.

Now in another paper I found this:


If you look at the above micrographs, you will see that the two patients that had relapsed (10710 and 10737) had IL-1b and IL-6 and TNF alpha missing. The macrophages were not activated!!!! The "Danger Signal" known as inflammation was missing! The non-responders most likely had their macrophages polarized to a M2-like phenotype by the Tregs and or IL-10.



So if the Macrophages are M2-like in the Tumor’s microenviroment, then if we control the Tregs, the upregulation of the of CTLA-4, PD-1 on the T-cells including the Tregs, and control the IL-10 production through anti-IL-10 antibody on the macrophages, we can shift the M2-like Macrophages into the M1 thus producing IL-12 shifting the differentiation of the Niave CD4+ T-cell the TH1 phenotype to activate the T-cells.


This all can be done with Yervor, Anti-PD-1 and Anti-IL-10 receptor antibody. You can get the tomor to shed antigentic protein by either whole radiation, Chemotherapy (TMZ- + Patrin-2) or Heat Shock.


CpG oligonucleotides induced NF-_B activation through the triggering of TLR9 signaling in TAM (Fig. 2), and the co-use of an IL-10 receptor Ab reduced IL-10 signaling in TAM, thereby reducing their M2 polarization.



Plasticity of Macrophage Function during Tumor Progression: Regulation by Distinct Molecular Mechanisms
Source: http://www.jimmunol.org/content/180/4/2011.full.pdf

HMGB1 from the dying tumors (irradiation, Chemotherapy, Heat Shock) will act as the Danger signal and bind to the TLR4 and activating the Macrophage (M1) and secrete IL-12 which acts upon the naïve CD4 T helper cells to differentiate to the Th1 phenotype.



petoh et al. has revealed an interesting role of TLR signalling in cancer therapy. They studied the immune-stimulatory properties of dying tumour cells after chemotherapy or radiation therapy. Using TLR4 and MyD88-deficient DCs, they show that TLR4 signaling is required for crosspresentation of antigens from apoptotic tumour cells on MHC class I to generate antitumour cytotoxic T cell (CTL) responses. Apetoh et al.also identified a “danger signal” from dying tumour cells, the nuclear protein highmobility group box 1 protein (HMGB1, see Figure) that triggers this protective immune response through activation of TLR4. According to their work, the interaction of high mobility group box 1 protein (HMGB1) released from dying tumour cells with Toll-like receptor 4 (TLR4) on dendritic cells is required for the crosspresentation of tumour antigens and the promotion of tumour specific cytotoxic T-cell responses.

So to sum it up, If you take Yervoy + Anti-PD1 + Anti-IL-10 along with radiation/Chemo could we get the right T-cell activation and Immune Response?

My guess you will activate the TLR4 pathway and induce the RIGHT IMMUNE RESPONSE.




So can we Get the Oncologists on board to propose and setup a clinical trial?
Time will only tell.
Remember the this blog. It will lead to a CURE!!!


“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”

~Charles Darwin~

Take Care,

Jimmy B

Identifying and Over Coming Immune Barriers at the Level of the Tumor Microenvironment..Melanoma .Jim Breitfeller

Eleventh International Conference on Progress in Vaccination Against Cancer

Dr. Thomas Gajewski
University of Chicago,Chicago,IL,USA

"Immunotherapeutic approaches for the treatment of melanoma, such as tumor antigen-based vaccines, can frequently boost immune responses. However, clinical responses as measured by tumor shrinkage are seen in only a minority of patients. This observation has prompted careful analysis of the tumor microenvironment for biologic correlates to clinical response and also to identify mechanisms of tumor resistance. Patients with advanced melanoma treated with antigen-specific vaccines had pre-treatment tumor biopsies analyzed by gene expression profiling. Supervised hierarchical clustering was performed based on clinical outcome. An expanded bank of tumors was analyzed to increase the sample size and better understand gene patterns.
Two major categories of melanoma metastases have been observed.

One subgroup of patient has an inflamed phenotype that includes expression of chemokines, T-cell markers, and other immunoregulatory factors. Clinical responders to melanoma vaccines appear to fall within this subset. This group also contains the highest expression of negative regulatory factors, including PD-L1, IDO, and FoxP3, suggesting that these immunosuppressive mechanisms may dominantly inhibit anti-tumor –cell function in those patients. In addition, absence of B7 expression supports classical T-cell anergy. Preclinical experiments have confirmed a critical role for these mechanisms in limiting anti-tumor T–cell efficacy in vivo, giving candidate treatment strategies for translation back into the clinic.

A second subset of patients is represented by tumors which are non-inflamed and lack chemokines for T cell recruitment. Therefore, a major barrier in these cases appears to be failed T –cell migration into tumor sites. Experimental strategies to augment T-cell migration can have important anti-tumor effects in preclinical models. The presence of the "inflamed" gene signature was associated with a type I IFN transcriptional profile, and murine experimental models have confirmed a critical role for type I IFN signaling in promoting adaptive immunity."


So,In the first subset, tumors had a suppresive nature that may be over riddden by Anti-CTLA-4 (Yervoy) and or Anti-PD-1 Therapy

The second subset was missing the "danger signal" inflammatory cytokines and chemoattractants most likely due to STAT3 signaling from the Tumor.

Stimulation of Toll-like receptor 4 (TLR-4) activates macrophages and results in the release of TNF-alpha. It is hypothesized that melanoma inhibits macrophage activation by suppressing TLR-4 signaling.








Cytokines are small proteins which allow cells of the immune system to communicate with one another via cytokine receptors expressed at the cell surface.
Activated macrophages defend against tumors by secreting cytokines to recruit secondary immune cells, presenting antigen to T cells, and by direct tumor cytotoxicity. Peritoneal macrophages harvested from melanoma-bearing mice are less cytotoxic to melanoma cells, and produce less superoxide, nitric oxide, and tumor necrosis factor-alpha (TNF-alpha) than those from nontumor-bearing mice. Similar impairment of macrophage activation occurs in vitro using media harvested from cultured melanoma cells.

Activated Macrophages secrete the following cytokines under different conditions:
IL-1,IL-12,IL-6, IFN-gamma/alpha/beta and TNF-alpha


IL-6


Interleukin 6 is a pro-inflammatory cytokine and is produced in response to infection and tissue injury. IL-6 exerts its effects on multiple cell types and can act systemically.

IL-6 stimulates liver secretion of acute phase proteins
IL-6 stimulates B-lymphocytes to produce antibodies
IL-6 in concert with IL-1b causes T-cell activation
IL-6 induces STAT 3 Signaling
IL-6 Plus TGF-b induces the Th17 cell phenotype


IL-1 beta

Interleukin-1b is a pro-inflammatory cytokine which is secreted by macrophages activated by a number of stimuli including TNF-alpha, bacterial endotoxin and IL-1b itself.
IL-1b exerts its effects on many different cell types locally at the site of production and systemically (at a distance).


IL-12


Interleukin-12 is a heterodimer consisting of a p35 and a p40 subunit. Both subunits are required for receptor binding and biological activity.
IL-12 stimulates growth of activated Natural Killer (NK) cells, CD8+ and CD4+ T- cells.
IL-12 increases NK and T-cell g-IFN production which shifts T-cell differentiation towards a Th1-type response.
IL-12 increases NK production of TNF-alpha which can act synergistically with IFN-gamma.
IL-12 suppresses IL-4 induced IgE production.


TNF-alpha


Tumor Necrosis Factor alpha is made by many other cells as well as macrophages, which are major sources, especially after priming by Interferon gamma.
TNF-alpha initiates a cascade of cytokines which mediate an inflammatory response. TNF-alpha effects are mediated through two types of receptor, a 75kDa TNFR-a receptor and a 55kDa TNFR-b receptor.
TNF-alpha regulates the expression of many genes in many cell types important for the host response to infection.

IFN-gamma/beta

Macrophages, and many other cells produce these Type I interferons which act as immunomodulatory, as well as antiviral cytokines. Distinct receptor from interferon gamma, mediates overlapping or competing effects on macrophages. Cellular signalling pathways involve Jak/Stats, and other pathways.

So, if Melanoma suppresses Macrophage Activation, then the tumor microenviroment is missing IL-6, IL-1b and other cytokines.

If you look at the above micrographs, you will see that the two patients that had relapsed (10710 and 10737) Had IL-1b and IL-6 missing. The macrophages were not activated!!!! The "Danger Signal" known as inflammation was missing!





The missing combination of IL-1 and IL-6 meant there is no T-cell activation. And no induction of the Th17 phenotype. It is now becoming a lot more clearer based on Dr. Gajewski's findings.


Now might be the time for a critical re-evaluation of our overall approaches to targeting STAT3 and for developing new models for disrupting the protein in order to accomplish the goal of delivering clinically useful direct STAT3 inhibitors as novel anticancer agents in a timely manner.






“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”

~Charles Darwin~
Take Care,
Jimmy B

MedImmune Inks Deal for Pfizer's Anticancer mAb Therapeutic..Melanoma .Jim Breitfeller

MedImmune inked an in-license agreement with Pfizer for tremelimumab, a mAb therapeutic for various types of cancer. Pfizer presented final toxicity results of a Phase I dose-escalation trial of tremelimumab in combination with gemcitabine in chemotherapy-naive patients with metastatic pancreatic cancer.

Under terms of the deal MedImmune will assume global development rights to tremelimumab. Pfizer retains rights to use the drug compound with specified types of combination therapies.

Pfizer previously signed over developments rights covering tremelimumab in melanoma to Debiopharm after the mAb failed in a Phase III melanoma trial. The interim analysis found that it would not offer any benefit over standard chemotherapy. Thus in April 2008, Pfizer was forced to halt the trial.

A full evaluation of the data revealed a biomarker that predicted patients who were more likely to respond, according to Pfizer. Debiopharm will be responsible for conducting a new Phase III study that leverages this marker to select patients with unresectable, stage IV melanoma. At the time of inking the deal with Debiopharm, Pfizer said it would retain all commercial rights.

Tremelimumab is a fully human mAb that binds to the protein CTLA-4, expressed on the surface of activated T lymphocytes. "Adding another immunotherapeutic approach to our oncology pipeline, one which may employ the immune system itself to fight cancer, exemplifies our continued commitment to embracing this new era of cancer care," says Bahija Jallal, Ph.D., MedImmune's evp, R&D.

MedImmune has seven clinical-stage mAb programs for cancer treatment. Phase I candidates bind to CEA and CD3, CD22, IGF, CD19, and Ang2. The Phase II candidate targets PDGFRα and is being tested in lung cancer and glioblastoma. The company believes that the platelet-derived growth factor receptor alpha (PDGFRα) pathway, with its potential role in regulating transformation as well as tumor microenvironment, progression, and metastasis, may be an important cancer target.

MEDI-575 is a fully human mAb to PDGFRα being tested in lung cancer. It has been shown to inhibit signaling from PDGFRα on cancer cells and supportive stroma. However, MEDI-575 reportedly does not inhibit PDGFRβ, the inhibition of which has been associated with significant clinical toxicities including extravascular fluid accumulation.

MEDI-575 is a fully human mAb to PDGFRα being evaluated as a treatment for glioblastoma multiforme. MEDI-575 has been shown to inhibit signaling from PDGFRα on cancer cells and supportive stroma but not PDGFRβ, MedImmune says


Bristol Myer Squibb will now be looking in the rearview mirror and seeing MedImmune in it. Down the road we may see the price of these anti-CTLA-4 antibodies go down.


Also MedImmune has an US Patent Application 20100028330 - METHODS OF UPMODULATING ADAPTIVE IMMUNE RESPONSE USING ANTI-PD1 ANTIBODIES.

This is becomming Very Intersesting!!!

A race for the CURE!!!!!




It is good to see some Competition.



“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”

~Charles Darwin~

Take Care,

Jimmy B

Understanding cancer immunotherapy..Melanoma ..Jim Breitfeller

Understanding cancer immunotherapy
By Dr. NG SOO CHIN

The basic premise of cancer immunotherapy involves enhancing the body’s own immune system to fight off cancer. It sounds logical and simple in concept, but the practice is complicated.

THE need for more effective and targeted therapy for cancer has always been in the minds of researchers and doctors who treat cancer. The traditional methods of treating cancer, ie surgery, radiation, and chemotherapy, have obvious limitations. Surgery would not be effective in disseminated or widespread diseases, while radiation and chemotherapy cause “collateral damage” due to effects on normal cells while killing off cancer cells. Certainly, a treatment modality utilising and enhancing our immune system to prevent or fight off cancer is a sound and attractive concept, hence the basic premise of cancer immunotherapy (CI).

The traditional methods of treating cancer, i.e surgery, radiation, and chemotherapy, have obvious limitations, hence the surge in interest in cancer immunotherapy. There is a general belief that failure of “immune surveillance” is a main contributory cause of cancer arising in an individual. There is also evidence that in many cancer patients, the immune system slows down the growth and spread of tumours. This means we need a competent immune system to prevent cancer, and to prevent it from spreading once cancer has started. The basis of CI, ie enhancing the body’s own immune system to fight off cancer, sounds logical and simple in concept. Unfortunately, like most things in life, the real scenario proves to be far more complicated, and the quest for effective cancer immunotherapy has taken a long time. But slowly and surely, we are unraveling the mysteries.

What are the ‘tools’ of CI?

To battle cancer cells with immunotherapy, we can either stimulate our immune system, or transfer antibodies or T cells from an outside source. Certainly, immunotherapy involving certain cytokines and antibodies has now become part of standard cancer treatment. Other examples of immunotherapy, especially those involving cellular therapy, remain largely experimental. Although many clinical trials of new forms of immunotherapy are in progress, an enormous amount of research and clinical trials need to be done before the findings can be widely applied.

What are the different types of CI available now?

The cytokines and monoclonal antibodies used are not called drugs or medication, but are labeled as biological immune response modulators (BIRMs), which include cytokines such as interferons, interleukins, colony-stimulating factors and monoclonal antibodies, plus cancer vaccines. We can further categorise them as below:

I. Immunostimulants

Immunostimulants are non-specific agents that tune-up the body’s immune defences. There have been some success with interleukin-2 (IL-2), a potent growth factor for T cells, which have been used in kidney and malignant melanoma, while alpha-interferon (IFN) are used for the treatment of chronic myeloid leukaemia and hairy cell leukaemia.

II. Monoclonal antibodies

Monoclonal antibodies are identical because they are produced by one type of immune cell – all clones of a single parent cell. Currently, most of the antibodies used are produced by recombinant DNA technology. The basis of monoclonal therapy is that different tumours have unique tumour antigens on their surfaces, and the identification of such antigens, such as CD20 on lymphoma cells, and the production of anti-CD20 antibody, ie rituximab, enables a targeted hit on the tumours. This will result in selective killing of lymphoma cells. Indeed, the advent of rituximab has changed the landscape of lymphoma treatment, with improvement in response and survival of patients. Similarly, other monoclonal antibodies such as herceptin (breast cancer), bevacizumab (lung cancer), and alemtuzumab (chronic lymphocytic leukaemia) are making waves in cancer treatment.

III. Immunotoxins and radioimmunotherapy

Monoclonal antibodies can be modified for delivery through toxin, radioisotope, cytokine or other active conjugates. Many such conjugates have been tried with some success. Mylotarg was licensed by the US Food and Drug Administration (FDA) for treatment of acute myeloid leukaemia (AML). Myelotarg is a combination of anti-CD33 and calicheamicin (a cytotoxic compound). However, it was recently withdrawn from the market due to potential severe liver damage. Monoclonal antibodies against tumour antigens can also be coupled to radioactive atoms. The goal with these agents is to limit the destructive power of radiation to those cells (cancerous) that have been “tagged” by the attached monoclonal antibody. Zevalin is a monoclonal antibody against the CD20 molecule on B cells (and lymphomas) conjugated to the radioactive isotope yttrium-90 (90Y). The results in treating B cell lymphoma with radioimmunotherapy are encouraging, though the delivery of such an agent is somewhat cumbersome.

IV. CI with T Cells (allografts or autografts of T cells)

T lymphocytes such as cytotoxic T lymphocytes (CTL) are capable of killing target or tumour cells. How to prime them to act appropriately, ie to kill tumour cells and not other normal cells, remains the challenge. The main reason why allogeneic bone marrow transplants (allografts) work is because of the the post transplant continual attacks on the tumour cells by T cells (graft versus tumour effect) seen in many patients. However the accompanying graft versus host reaction can be severe enough to result in significant mortality and morbidity to the transplant recipient. The same effect of such immunological attacks on tumour cells can be harnessed by donor lymphocyte infusion. This is a double edged sword and needs to be used with extreme caution. Infusion of own or autologous T cells or genetically modified T cells have been attempted with limited success.

V. Cancer vaccines

The response of the patient’s own immune system – immune surveillance – has clearly failed in cancer patients. The purpose of cancer vaccines is to elicit a more powerful active immunity in the patient. Several approaches are being explored. The name “cancer vaccines” is somewhat misleading, as these vaccines are developed to cure cancer and not to prevent it. Dendritic cells (DC) are the most potent antigen-presenting cells. They engulf antigens, process them into peptides, and “present” them to T cells. The making of the vaccine entails, firstly, harvesting DC from patients and exposing them to tumour specific antigens. By injecting the “stimulated” DC back to the body, they may be able to elicit a strong immune response and attack the tumour, utilising the stimulated cytotoxic T lymphocytes. On April 29, 2010, the FDA approved the first anti-cancer vaccine, a patient-specific dendritic cell vaccine for use against advanced prostate cancer. Tumour-antigen specific vaccines are used to immunise the patient with an antigen universally expressed by tumours of that type (but not by normal cells), mixed with some form of adjuvant that will enhance the response. Unlike patient-specific vaccines, these vaccines can be mass-produced for use in anyone with the appropriate tumour.

What are the strengths of immunotherapy?

The most appealling point of CI is that potentially, this is a targeted therapy, and hence the side effects to normal cells would be considerably less. Some chronic myeloid leukaemia patients with relapsed disease post-bone marrow transplant managed to attain long term survival after donor lymphocyte infusion. CI is a very powerful tool indeed, if only we know how to apply it optimally, but we are still grappling how best to titrate the graft versus leukaemia response. Because the side effects are different from conventional chemotherapy, the combination of cytotoxics and immunotherapeutic agents such as rituximab has improved the outcome in lymphoma patients without additional side effects. Because of the favourable safety profile, CI can be given in repeated courses, unlike cytotoxics, which are limited by their cumulative toxicities.

What are the weaknesses or problems of immunotherapy?

The main problem is likely to be the need for time for the immune system to respond to CI, and in some patients with cancer which behaves like a runaway train, eg Burkitt’s lymphoma, time is what the patients do not have. CI is unlikely to work in a large volume tumour, and the tumour needs to be debulked (reduced in size) before CI has a chance to work. CI is costly, and the price is not likely to go down in the near future. Monoclonal antibodies are fabulously expensive. This is even so for a personalised vaccine. For patients who have financial constraints, money is not everything – it is the only thing! Hence, it is likely that such treatment may not be available to those who need it, unless some assistance programme is forthcoming. It is unlikely that CI alone can cure a cancer in the setting of cancer patients whose immune systems have failed them in the first place. We need to learn and strategise how to put different treatment modalities, ie chemotherapy, CI, radiotherapy, in a winning treatment combination. The answer can only come with more painstaking research and careful clinical trials.

Is immunotherapy devoid of side effects?

A resounding NO. Any form of treatment can potentially give rise to side effects. Even taking paracetamol can cause severe allergic reactions, although rarely. Rituximab commonly gives rise to infusion reactions, which are manageable. In 2006, in one of the phase 1 trials of a T cell stimulatory monoclonal antibody called TGN1412 in England, all six of the volunteers were nearly killed, and ended up with multiple organ damage due to unrestrained generalised T cell stimulation. So forget about the no side effects talk. I believe the side effects of immunotherapy are different from conventional treatment like chemotherapy, and we have to learn about them (both short term and long term), and deal with them accordingly. For instance, we now know that the use of chemo-immunotherapy in treating non-Hodgkin’s lymphoma can cause potentially fatal hepatitis B virus activation. This problem is prevented by concurrent antiviral therapy. How does CI fit into a patient’s treatment plan? Can a patient ask for immunotherapy first before following established treatment or can CI be the sole form of treatment? I feel the best person to answer the question is the oncologist/haematologist who is looking after the patient. CI with monoclonal antibodies can be used in induction (initial treatment) or to consolidate the treatment, and in some instances, to remove any minimal residual disease. Cell-based immunotherapy remains experimental and is likely to be offered in a setting of clinical trials. Very rarely is CI used as the sole form of therapy. I honestly feel that clinicians should make the decision. Using inappropriate therapy results in loss of valuable time in tackling the cancer, not to mention the accompanying financial toxicity!

What are the basic questions to ask when one checks out immunotherapy?

The patient really needs to know what he or she is in for. Is the centre a reputable one, and is the treatment approved by authorities such as the FDA or EU (European Union)? Is the treatment potentially curative or merely palliative? Are there other treatment options which may work just as well? What does the procedure entail and what are the potential side effects? The patient, together with the attending doctor, should weigh the benefit versus risk equation, and also the cost effectiveness of the planned treatment. In other words, one should go into any treatment only with eyes widely open. When a treatment sounds too good to be true, it usually is.

Is CI ready for prime time?

It is important to keep our feet firmly on the ground and not be taken by sales propaganda. In some forms of CI, such as monoclonal antibodies treatment, many lives are prolonged and saved, and monoclonal antibodies is now an established treatment modality. We need to tread far more carefully in cell based therapy. To date, the FDA has only approved one, and only one, cancer treatment vaccine, i.e. Provenge (sipuleucel-T). The vaccine is designed for men with advanced prostate cancer who have limited treatment options. Patients will have immune cells purified from their blood, and then combined with a specific protein (an antigen) that stimulates the immune cells to recognise and kill prostate cancer cells. The custom created vaccine is given intravenously in three doses, two weeks apart. Potential reactions include fever and flu-like symptoms. Before we get carried away, the new treatment resulted in a very modest 4.1 month improvement in median survival compared to the placebo group.

Why the surge in interest in CI?

According to the American Cancer Society, immunotherapy, especially cancer vaccines, is still a small field which hasn’t yet proven itself to be better than other types of cancer treatments. However, it’s one that researchers say holds a lot of promise and “many future advances against cancer will probably come from this field”. Interestingly, Time magazine voted in two cancer researchers, Dr Larry Kwak and Dr Doug Schwartzentruber, for its 2010 list of 100 most influential people in the world. Both of them are in the forefront of cancer vaccine research. Dr Kwak is involved in BiovaxID patient-specific vaccine for follicular lymphoma while Dr Schwartzentruber is researching a melanoma vaccine. Both vaccines had good phase 3 trial results and may make their way to bedside use soon. Is there a need for regulation of CI in Malaysia? The answer has to be yes. Unfortunately, we have no shortage of entrepreneurs, and for new therapies, whether it’s stem cell based or cell based, medical supervision is necessary to protect our patients. We don’t want to make news for the wrong reasons. At the end of the day, we should heed Hippocrates’ wise words – to cure sometimes, to comfort always, and not to cause any harm to our patients. This article is contributed by The Star Health & Ageing Panel, which comprises a group of panellists who are not just opinion leaders in their respective fields of medical expertise, but have wide experience in medical health education for the public.

The members of the panel include:

Datuk Prof Dr Tan Hui Meng, consultant urologist; Dr Yap Piang Kian, consultant endocrinologist; Datuk Dr Azhari Rosman, consultant cardiologist; A/Prof Dr Philip Poi, consultant geriatrician; Dr Hew Fen Lee, consultant endocrinologist; Prof Dr Low Wah Yun, psychologist; Datuk Dr Nor Ashikin Mokhtar, consultant obstetrician and gynaecologist; Dr Lee Moon Keen, consultant neurologist; Dr Ting Hoon Chin, consultant dermatologist; Prof Khoo Ee Ming, primary care physician; Dr Ng Soo Chin, consultant haematologist.

For more information, e-mail starhealth@thestar.com.my. The Star Health & Ageing Advisory Panel provides this information for educational and communication purposes only and it should not be construed as personal medical advice. Information published in this article is not intended to replace, supplant or augment a consultation with a health professional regarding the reader’s own medical care. The Star Health & Ageing Advisory Panel disclaims any and all liability for injury or other damages that could result from use of the information obtained from this article.

Source: http://thestar.com.my/health/story.asp?file=/2011/4/3/health/8389839&sec=health

“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”

~Charles Darwin~

Take Care,
Jimmy B

“Schedule and Dose for Combination Therapy,” Melanoma.. 2011 Scientific Colloquium of the Cancer Immunotherapy

“Schedule and Dose for Combination Therapy,”
2011 Scientific Colloquium of the Cancer Immunotherapy Consortium
• Thursday, March 17, 2011 7:00 AM - Saturday, March 19, 2011 1:30 PM
Eastern Time


First Speaker: Dr. Rafi Ahmed
Director of the Emory Vaccine Center

"As a basic immunologist, EVC Director Dr. Rafi Ahmed studies immunological memory – the ability of the immune system to “remember” a particular antigen and respond accordingly. Dr. Ahmed and his colleagues have made significant discoveries about how immune memory cells are created and how long they survive; understanding these mechanisms is crucial to the development of vaccines for HIV and other infectious agents. In addition to contributing vitally to vaccine science, Dr. Ahmed’s findings are being applied to research into therapies for the treatment of cancer and the prevention of organ rejection."




Dr. Rafi Ahmed is now being introduced by Johannes Vieweg, & highlighting his work on immunological memory

Dr. Ahmed is sharing how lessons from immune memory development in chronic viral infection can inform cancer immunotherapy field

Ahmed: wait 30-60 days to boost in vaccination produces better immune responses for many types of viral vaccines. Same for cancer?JimmyB :Why 30 to 60 days? Because this is the time factor that it takes for the CD4+ and CD8+ T-cells to grow and differentiate into effector T-cells. (See Graph)




Fig-1

Dr. Rafi Ahmed is now being introduced by Johannes Vieweg, & highlighting his work on immunological memory Dr. Ahmed is sharing how lessons from immune memory development in chronic viral infection can inform cancer immunotherapy field Ahmed: wait 30-60 days to boost in vaccination produces better immune responses for many types of viral vaccines. Same for cancer?
Fig-2

Ahmed: Synergy we've seen combining PD-1 with IL-2 (negative + positive signal) in viral infection therapy have been astonishing.

Jimmy B:Imagine if you combine CTLA-4 + PD-1 and IL-2. The Holy Grail of Immuno therapy I believe.Ahmed raises point that mTOR inhibition may enhance vaccine-induced memory CD8 T-cells. Role for combining with cancer vaccines?

Much audience Q&A for Dr. Ahmed - when see exhaustion clinically, is it inhibition, effect of dose of IL-2, and role of autophagy?

Source: Cancer Research on Twitter

http://twitter.com/#!/search?q=%23cic11












“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~
Take Care,

Jimmy B

MSKCC to Test Agenus' Personalized Cancer Vaccine in Combination With Novel Immunomodulatory Agents Melanoma..Jim Breitfeller

MSKCC to Test Agenus' Personalized Cancer Vaccine in Combination With Novel Immunomodulatory Agents

LEXINGTON, Mass., Jan. 24, 2011 (GLOBE NEWSWIRE) -- Agenus Inc. (Nasdaq:AGEN) today announced it has entered into a research agreement with Memorial Sloan-Kettering Cancer Center (MSKCC) using Agenus' proprietary cancer vaccine technology.

The collaboration will test Agenus' cancer vaccine in combination with antibodies that are intended to target specific markers on tumor cells, such as CTLA-4 and PDL-1. This group of antibodies represents a new class of immunotherapeutic agents that are thought to have complementary mechanisms of action with cancer vaccines. The studies will be performed in the laboratory of Jedd D. Wolchok, M.D., Ph.D., a leader in the field of cancer immunotherapy. Dr. Wolchok serves as the Associate Director of the Ludwig Center for Cancer Immunotherapy at MSKCC as well as Director of Immunotherapy Clinical Trials.

"Collaborating with MSKCC and Dr. Wolchok's laboratory opens a new chapter in the development of our personalized cancer vaccine portfolio for targeting later stages of this disease," said Garo Armen, Ph.D., CEO of Agenus. "Partnerships with leading institutions are central to Agenus' strategy to bringing life-changing products for cancer patients to market faster."

Agenus' cancer vaccine is designed to expand and specifically program the army of T-cells responsible for killing tumor cells; however, as cancer grows it becomes smarter and increasingly builds an 'immune fortress' that can protect itself from the attack of T-cells. Therefore, combining a product that activates T-cells with an agent that blocks the signal preventing the T-cells from effectively killing the tumor could have highly potent outcomes.

"Combination immunotherapy in cancer is increasingly becoming a key focus of research, and this collaboration will add to this important and growing knowledge base," said Dr. Wolchok. "Our interest in Agenus' cancer vaccine is that it contains many antigens that are genetically matched with the cancer as the product is derived from the tumor itself."

"In addition to this preclinical research effort, we are looking forward to opportunities to rapidly initiate clinical trials, combining our Prophage series of cancer vaccines with either marketed or investigational agents that work against T-cell down regulation," said Dr. Armen.

Source:Personalized Cancer Vaccine in Combination With Novel Immunomodulatory Agents


Combinatorial therapy will lead us toward a cure. Mark my words.

“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~
Take Care,
Jimmy B

The Accelerator..IL-2 Therapy..Melanoma Cancer..Jim Breitfeller

The Food and Drug Administration this year approved a “cancer vaccine” for prostate cancer called Provenge, so-called because it trains the immune system to attack the patient’s tumors. Most such vaccines focus on a single type of cancer, or are even tailored to individual patients.

Ipilimumab, by contrast, is a more general immune booster. It blocks a protein called CTLA-4 that acts as a brake on T cells, the soldiers of the immune system. It is already also being tested against lung and prostate cancer.

Still, if a tumor does not elicit a strong immune response to begin with, then just keeping the response going longer would not help much, just as lifting one’s foot from the brake usually will not make a car go faster if the accelerator is not pressed. The accelerator needed is Interluekin-2 (IL-2.

IL-2 induces inflammation at tumor sites(Danger Signal) with three predominant secondary effects:

1)activation of antigen-presenting monocytes.

2) massive production of chemoattractants that may recruit other immune cells to the tumors.

3) activation of cytolytic mechanisms in monocytes (calgranulin, grancalcin) and NK cells NKG5, NK4.

The take away; systemic combinatorial therapy is one of the best ways to utilize the immune system to induce an immune response to Melanoma Cancer.





“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~

Take Care,

Jimmy B

Tumors shut down the Third Signal needed for T-cell Activation..Melanoma Cancer..Jim Breitfeller

A picture is worth a thousand words.

STAT-3 signaling from the tumors blocks the pro-inflammatory cytokines, so no danger signal is sent to the immune system.




The Missing Link in T-cell activation using a Vaccine, "The Danger Signal"

DCs leads to enhanced induction of Th17-1 cells. These data demonstrate the capacity of DCs to induce expansion of polyfunctional IL17-producing T cells in humans, and suggest a role for DCs in the enrichment of Th17-1 cells in the tumor bed.

Tumor bed is heavily infiltrated by DCs, which, as shown here, are the most efficient inducers of human Th17 cells. The data supports a model in which Th17 cells are recruited to the tumor bed by Th17-attracting chemokines (eg, CCL20, recently shown to be enriched in the melanoma tumor bed) and activated to a Th17 phenotype locally by tumor-infiltrating DCs. The capacity of DCs to induce Th17 cells may be further enhanced by the uptake of apoptotic tumor cells, as well as inflammatory cytokines (eg, IL1, IL6, TNF) in the tumor bed. This gives rise to T-cell activation and the inflamed response leading to immune response.


For the tumor to survive the immunologic suppression system, it must turn on pathways (such as Stat3) that inhibit production or sensing of proinflammatory danger signals that activate innate and adaptive immune responses. Tumors that successfully accomplish this can shift the balance of immunity from activation to tolerance induction. Pardol et al But what if, the production of Proinflammatory cytokines can over come the suppressive function of the tumor’s microenvironment? Could the differentiation of the CD4+ T-cells into Th17 be the path to activation and immunity responses? If that is the case, then Anti-CTLA-4 blockade (ipilimumab) plays more of a major factor in adaptive immunity then we originally thought.




“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~
Take Care,
Jimmy B

The Future of Immunotherapy.. Emerging concepts in biomarker discovery.Melanoma.Jim Breitfeller

Emerging concepts in biomarker discovery!!!!!2009

Take away: Get your blood and tumors profiled for Biomarkers. It could lead you to the right therapy to do.

A table of:
Emerging biomarkers potentially useful for the immunotherapy of cancer.

A Table of:
Emerging biomarkers potentially useful for the immunotherapy of cancer.



Source:Emerging concepts in biomarker discovery; The US-Japan workshop on immunological molecular markers in oncology



Dr. Kirkwood give his honest opinion on the clinical trails to date and where they are heading in the future incliding Biomarkers.



Please take an hour out of you day to view and listen, It may save you or your love one from doing the wrong therapy.

Dr. Kirkwood talks about autoimmunity through out the presentation
NIH Scientists Discover Secrets Of Helper T Cells Involved In
Autoimmunity.... Th17 cells!!!!!!









“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.

”~Charles Darwin~

Take Care,
Jimmy B

NIH Scientists Discover Secrets Of Helper T Cells Involved In Autoimmunity..Melanoma..Jim Breitfeller

NIH Scientists Discover Secrets Of Helper T Cells Involved In Autoimmunity
October 21, 2010

A race for a cure!!!!!!! Let the games begin!!!!!


WHATScientists at the National Institutes of Health have redefined the roles of several cytokines involved in the generation of immune cells implicated in severe autoimmune diseases. The study in mice showed that development of Th17 immune cells can occur without the presence of transforming growth factor (TGF)-beta, a mediator thought to be required for Th17 cell development. The study demonstrates that the interaction of three inflammatory cytokines (proteins that influence the behavior of cells) - interleukin-6 (IL-6), IL-1-beta and IL-23 - is responsible for the creation of Th17 cells that are more active in promoting autoimmunity than Th17 cells generated with IL-6, IL-1-beta and TGF-beta. These findings reemphasize the separate roles of IL-23 and TGF-beta in immunity and autoimmunity, and open up possibilities for the development of new therapies. The study appears in the current issue of the journal Nature.

The immune systems of mice and humans mainly consist of B cells and T cells. While B cells fight infections and can induce autoimmunity by producing antibodies that directly target foreign antigens or a person's own tissue, T cells are involved in overall cell-mediated immunity. Importantly, how a T helper (Th) cell differentiates (develops from an immature, unspecialized cell into a mature, specialized cell) determines how it mediates immune responses. Th17 cells produce IL-17, a powerful inflammatory cytokine, and have been implicated in multiple autoimmune diseases, including rheumatoid arthritis, psoriasis and multiple sclerosis. The established belief has been that Th17 cells initially differentiate in response to activation by IL-6 and TGF-beta. However, previous research has shown that TGF-beta is primarily associated with suppressing immune functions and promoting regulatory T cells (Treg), which can produce inhibitory cytokines that dampen inflammatory immune responses.

In the present study, the NIH scientists first looked at the conditions to differentiate Th17 cells from naïve T cells outside of the mouse (in vitro) and tried several different cocktails of cytokines to see which combinations would promote Th17 development. They found two combinations that efficiently induced Th17 differentiation. As previously described, IL-6, IL-1-beta, and TGF-beta-1 together created Th17 cells. Surprisingly, IL-6, IL-1-beta, and IL-23 without TGF-beta also created Th17 cells. Most interestingly, the action of Th17 cells generated with IL-23, designated Th17(23), was different from the action of Th17 cells generated with TGF-beta (Th17(beta)). The researchers compared transcription factors, receptors and mediators of the two Th17 subtypes and looked at the pathogenic activity of both Th17 subtypes in mice during experimental autoimmune encephalomyelitis (EAE), a common model of autoimmunity that mimics some aspects of multiple sclerosis. They found that Th17(23) cells provoked significantly more severe disease than did Th17(beta) cells.

These findings suggest a new model for Th17 generation and the existence of functionally different subtypes of Th17 cells. This study also provides a better understanding of the array of immune components involved in autoimmunity and suggests possibilities for new targeted therapies.

NIH scientists contributing to this study are affiliated with the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), the National Institute of Dental and Craniofacial Research (NIDCR), and the National Institute of Allergy and Infectious Diseases (NIAID). Additional support was provided by Merck Research Laboratories (Schering-Plough Biopharma), Palo Alto, Calif.

REFERENCE
Ghoreschi K, Laurence A, Yang XP, Tato CM, McGeachy MJ, Konkel J, Ramos HL, Wei L, Davidson T, Bouladoux N, Grainger J, Chen Q, Kanno Y, Watford WT, Sun HW, Eberl G, Shevach E, Belkaid Y, Cua DJ, Chen W, O'Shea JJ. Enhanced Pathogenicity of Th17 cells Generated in the Absence of Transforming Growth Factor-ß Signaling. Nature. 2010 October 21;467(7318): 967-971.

WHO
John J. O'Shea, M.D. Scientific Director, National Institute of Arthritis and Musculoskeletal and Skin Diseases, is available to comment on this article.

CONTACT
To schedule interviews, please contact Trish Reynolds, 301-496-8190, .

About National Institute of Arthritis and Musculoskeletal and Skin Diseases
The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health (NIH), is to support research into the causes, treatment, and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information, visit http://www.niams.nih.gov.

About The National Institute of Dental and Craniofacial Research
The National Institute of Dental and Craniofacial Research (NIDCR) is the Nation's leading funder of research on oral, dental, and craniofacial health. For more information, visit http://www.nidcr.nih.gov/.

About National Institute of Allergy and Infectious Diseases
The National Institute of Allergy and Infectious Diseases (NIAID) conducts and supports research -- at NIH, throughout the United States, and worldwide -- to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses. For more information, visit http://www.niaid.nih.gov.

About National Institutes of Health
The National Institutes of Health (NIH) -- The Nation's Medical Research Agency -- includes 27 Institutes and Centers and is a component of the U.S. Department of Health and Human Services. It is the primary federal agency for conducting and supporting basic, clinical and translational medical research, and it investigates the causes, treatments, and cures for both common and rare diseases. For more information, visit www.nih.gov.

SOURCE: National Institutes of Health

NIH Scientists Discover Secrets Of Helper T Cells Involved In Autoimmunity
October 21, 2010




“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~
Take Care,

Jimmy B

Dilated capillaries at the melanoma tumor’s microenvironment caused by inflammation cytokines is the beginning of the “Danger Signals”.Jim Breitfeller

Three major events must occur to induce CD8+ T cell–mediated, tumor-protective immunity against melanoma.


First, the T-cell receptor must be triggered by a (or multiple) self antigen–derived peptide MHC class I complex. Therefore, this event depends entirely on appropriate antigen presentation, which is most efficiently provided by mature dendritic cells. Peripherally tolerant or “ignorant” self-reactive T-cell clones, once properly activated, may serve as tumor-specific effector T cells.

Second, simultaneously with T-cell receptor triggering, a distinct second costimulatory signal must be delivered, mediated by IL-2, B7-1, or B7-2, which engage IL-2 receptors and CD28 on the surface of the T cell, respectively (17). A source of these cofactors for effective CD8+ T-cell stimulation can be provided by CD4+ T cells that release critical amounts of IL-2, or by mature dendritic cells that display an increased level of B7-1/B7-2 costimulatory molecules on their cell surfaces.

Third, inflammatory cytokines, including IL-1, IL-6, IL-12, and IFN-γ provide a third signal that acts directly on T cells, referred to as the “danger signal”. This signal was found to optimally activate TH1 differentiation and lead to clonal expansion of T cells.1




The inflammatory cytokines act to promote T cell responses. They include IL-1, IL-6, IL-12, TNF-α, and IFN-g produced by macrophages and/or dendritic cells. Th17 cells also plays a part by secreting IL-17 and others. The most notable role of IL-17 is it involvement in inducing and mediating proinflammatory responses. Neutrophils are the earliest cells to arrive at the inflammatory site.

While TGF-β is a critical differentiation factor for Treg cells, IL6 completely inhibits the generation of Treg cells induced by TGF-β. Instead, IL6 and TGF-β together induce the differentiation of pathogenic Th17 cells. With IL-6 missing in the microenvironment, Treg Cells flourish.

If the CD4 + T cells differentiate into TH2 cells that produce IL-4, the other cells inhibited to produce IL-6. IL-4 was found to inhibit TNF-α and IL-1β by activated monocytes almost 100 %. The Secretion of IL-6 was decreased by approximatly 80 % in the presences of IL-4 Cytokine. TE Velde et al 1990


Neutrophil recruitment can also be induced by cytokines such as IL-17 and Tumor necrosis factor (TNF). Among the family of IL-17 cytokines, IL-17A and IL-17F are able
to promote the recruitment of monocytes and neutrophils via the induction of other cytokines and chemokines such as G-CSF and IL-8 by various cell types.

IL-17 appears to be involved in promoting neutrophil influx into the tumor site. With the influx of neutrophils in the tumor’s microenvironment and the inflammatory cytokines, capillaries at the melanoma tumor’s microenvironment become dilated, making room for the recruitment of immune cells.

Neutrophils also play an important role in promoting or suppressing the Th1 immune response, which is mediated partly by induction of cytokines or chemokines. Depending on the compositional makeup of the microenvironment, the neutrophils can promote the right immune response. Studies revealed that these neutrophils secreted three different chemokines. Some of these chemokines are known as chemoattractants. A chemoattractant is a chemical (chemotactic) agent that induces an organism or a cell, a leukocyte, to migrate toward.






These chemokines, MIP-1alpha, MIP-1beta, and MCP-1 are recently reported to serve as chemoattractants for Th1 cells. MIP-1alpha and MCP-1 are also reported to enhance antigen-specific (CTL) Cytotoxic T Lymphocyte induction. Studies revealed that MIP-1alpha /beta released from neutrophils are involved in recruitment of macrophages, T cells, monocytes, dendritic cells (DC), neutrophils and NK cells.
MIP-1 attracts predominantly CD8+ T cells while MIP-1 attracts CD4+ cells, although there is some overlap between subsets in response to both chemokines.

The other Chemokine MCP-1, binds to CCR2 to accumulate monocytes/macrophages, DC, T cells, and NK cells, thereby playing an important role in innate and adaptive immunity. CCR2 is Chemokine receptor that is key determinant of leucocyte trafficking.
IL-2 strongly upregulates expression of CCR2. With the MCP-1/CCR2 interface, the cells can traffic towards the tumor’s microenvironment. The trafficking of the cells and inflammatory cytokines present the perfect storm in the tumor’s microenvironment to induce the right immune response to eradicate the cancer, Melanoma.






Neutrophils circulate in the bloodstream and must be signaled to leave the bloodstream and enter tissues. The signal often comes from the bacteria themselves, from complement proteins, or from damaged tissue, all of which produce substances that attract neutrophils to a trouble spot. (The process of attracting cells is called chemotaxis.)


The combination of chemoattractants and inflammatory cytokines, in the tumor’s microenvironment, helps to send out a Danger Signal which in turn invokes the right immune response to eradicate the Melanoma tumors.






“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.”
~Charles Darwin~

Take Care,

Jimmy B