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

Questions and Answers from Jim In Denver Co..Melanoma..Jim Breitfeller

Jim,
First of all thank you for replying to my post. I usually don’t get many replies. When I talk to my wife about this, within the first five minutes she is telling me “I am loosing her.” It has taken me close to three years to get to where my knowledge on melanoma and the immune system is today. I don’t mean to talk over patient heads. It is just the scientist in me. I worked at Eastman Kodak’s Research laboratories for 25 years.

Now to answer you first question:

You have said that the most effective durable treatment for advanced melanoma would consist of Ipilimumab combined with IL2 - is that correct?

Based on my research today, IL-2 and Anti-CTLA-4 (Ipilimumab) are most durable as we speak. A new phase I therapy is showing great promise with less side effects. That is anti-PD-1 Therapy. These therapies don’t need a specific HLA type to get into the trials.

There is also a very, very ,very new therapy that is still in translational stage. Translational research is a way of thinking about and conducting scientific research to make the results of research applicable to the population under study and is practised in the natural and biological, behavioural, and social sciences. It is usally conduted with animals like rats, mice, monkeys.



Anyway this therapy combines the Anti-CTLA-4 and Anti-PD-1. It has shown synergistic results.



If you have c-Kit or BRAF mutations, then targeted therapy may used but may not be durable.

If you are HLA-02 Positive, You have the option of ACT therapy with Dr. Rosenberg or Dr. Patrick Hwu at NCI or MD Anderson. They have gotten 72 % response rate with I think about 36 % complete response is I am not mistaken.

Second Question:
There are no studies currently availble that combine Ipi and IL2, is that correct?
Define combine? There was a clinical study done by Dr. Rosenberg and colleages.



As you can see in the graph above, IL-2 was added prior to the maximum propagation of the CD4+ T helper cells. IL-2 is known as a growth factor. So what I believe happened in this trial, they grew the Tregs.

IL-2 treatment during the expansion phase was detrimental to the survival of rapidly dividing effector T cells. In contrast, IL-2 therapy was highly beneficial during the death phase, resulting in increased proliferation and survival of Tumor-specific T cells. IL-2 treatment also increased proliferation of resting memory T cells in the host that controlled the disease. A tumor-specific T cell in chronically infected Host also responds to IL-2 resulting in decreased tumor burden. Thus, timing of IL-2 administration and differentiation status of the T cell are critical parameters in designing IL-2 therapies (Blattman et al., 2003).


So what I am trying to say is you do the Ipilimumab therapy first. Wash out for about 50 days, and then start IL-2 Therapy.

Take away: It is a systemic combination with dosing and timing involved. Systemic Combinatorial Therapy.


Question 3:

If someone were to choose to do a combination treatment on their own (i.e. get IL2 following a course of Ipi through one of the clinical trials), would there be an advantage
to starting IL2 as soon as possible after stopping Ipi? Is there a time frame after which there would be no advantage to having received Ipi prior to taking IL2?

Base on papers from ITOH etal and others, 49 days after activation is at the maximum growth phase for the CD8- T-cells that mature into Cytotic T Lymphocytes.

Results: Graph setup

Kinetic Study of rIL-2-induced Expansion. In all 12 metastatic melanomas tested, a substantial proportion of TIL was present in tumor cell suspensions.
The ratio of lymphocytes to tumor cells ranged from 0.03 to 1.25 with an average ratio of 0.40 t 0.37. By fluorescence analysis,
TIL consisted of 78 days 11% CD3
T cells, 33 days 10% CD4+
T cells, 49 days 17% CD8+
Their CD4/CD8 ratio was 0.67.
(ITOH et al., 1988)

It was also reported that there is a time factor involved.
Our results show that T4 + human T cells differ substantially from T8 + cells with respect to their IL-2 responsiveness. T4 + cells cease to proliferate well before T8 + cells during a primary response. (GULLBERG AND SMITH et al.,1986)

Is there a time frame after which there would be no advantage to having received Ipi prior to taking IL2?

Yes, Ipilimumab has a half life of 15 days. So say you get one dose at 3.0 mg/Kg.

Days-- concentration
0-- 3
15-- 1.5
30-- 0.75
45-- 0.375
60-- 0.1875
75-- 0.09375
90-- 0.04687
105-- 0.02343
120-- 0.01171
135-- 0.00587
150-- 0.00292
165-- 0.00146
180-- 0.00073



It gets more complicated when you get multiple doses. Four dose regiment.

Days-- concentration
0-- 3
15-- 1.5
30-- 3.7
45-- 4.85
60-- 5.425
75-- 2.7125
90-- 1.35625
105-- 0.68
120-- 0.34
135-- 0.17
150-- 0.08
165-- 0.04
180-- 0.021

I am not sure where the limited threshold is but, at day 49 you have close to the maximum concentration of Ipilimumab in your body.

Since I used Tremelimumab with Half Life = 21 days and did 15mg/Kg

I had at day 50 approximately 2.17 mg/Kg anti-CTLA-4 level in my body

If I had to venture an educational guess, I would say after a four dose regime, you have 75 days to do the HD IL-2.

To back this theory up, we will use a chart from Dr. Wolchok experience the Ipilimumab.

It is a chart with the Absolute Lymphocyte count. (ALC). It is the CD4+ T-cells and CD8+ T cells combined.




As you can see from the graph, the maximum ALC was about week 7.
Week seven correlates to 49 days. That is when CD8+ T cells are at their maximum growth.



Question 4:

Last, is there any evidence that IL2's efficacy is enhanced by combining it with other agents (i.e. Biochemotherapy), either with or without first receiving Ipi?


This my take on the situation. You need the tumor-specific antigen to presented to the T-cells as signal 1. That could be a vaccine, radiation therapy or chemo to shed the antigen.
Secondly you need the costimulation of the CD28/B7 interface. By using Ipilimumab that blocks the CTLA-4 receptor from binding to the B7 molecule and shutting down the response.
Anti-CTLA-4 (ipilimumab) also blocks the CTLA-4 receptor on the Treg cells subduing their surpress function.

Third you need a “Danger Signal” to get the cell to migrate to the tumor site. This may be done with inflammatory Cytokines like IL2, IL17, IL-1,IL-12,IFN gamma that act directly on the T-cells. This signal was found to optimally activate the Th1 differentiation and lead to the clonal expansion of the T-cells.
It has come to light recently that Ipilimumab helps also in the differentiation by tilting the balance towards Th17 cells. These cells secrete IL-17 which recruite the neutrophils. This all takes place at the tumor’s microenviroment. The neutrophils secrete chemokines that are chemoattractants.

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.
So to answer your question, is there any evidence that IL2's efficacy is enhanced by combining it with other agents (i.e. Biochemotherapy), either with or without first receiving Ipi? yes if you know and take a systemic approach. You need to activate the t-cells before introducing IL-2. IL-2 can be the activator for small patient population.

As for Ipilimumab going it alone, like IL-2 can be the activator for small patient population. But when you do a systematic combinatorial therapy, there can be a synergetic result, complete response.
I hope I answered you questions, and please don’t hesitate to ask them. I do all this time by requesting reseach papers from around the world. Each question is a learning tool. There are no stupid questions. Knowledge is power to make an educated decision. Your Life may depend on it. There are many paths to take. Just follow the yellow brick road to complete response.




“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

The Missing Link in T-cell activation using a Vaccine, "The Danger Signal"Melanoma..Jim Breitfeller

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.

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 approximatly 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 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 and invoke a robust immune response to the Melanoma Cancer.

“Our data altogether suggest the following model: Th17 cells go to the tumor site and, by secreting IL-17, activates residential cells to produce CCL2 and CCL20, which provokes the mobilization of DCs and other leukocytes to the tumor site. DCs uptake tumor antigens in the lung or tumor site and migrate to the lymph nodes where they activate CD8+ T cells against the tumor. The new wave of effector CD8+ T cells migrates back to the lung or tumor site and kills established tumors.

Therefore, our data demonstrating that Th17 cells and IL17 participate in antitumor immunity by facilitating T cell recruitment to the tumor site and CD8+ T cell priming and effector differentiation suggests a new avenue for developing Th17 cell-based therapy for tumors or chronic viral infections and as an adjuvant for vaccinations.”

(Dudley and Rosenberg, 2007; Rosenberg and Dudley, 2004)

Conclusion: We not only want to supress the Tregs, we also need to produce the "Danger Signal" to optimally activate TH1 differentiation and lead to clonal expansion of T cells to generate a robust tumor-specific immune response.






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


“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