Source: Radiation Blast May Turbocharge Bristol-Myers Melanoma Drug
Recent evidence shows that the anti-tumor immune response elicited by radiation therapy or chemotherapy is due to the release by dying tumor cells of HMGB1, which acts on TLR4/MyD88 on dendritic cells.
It has been known that if radiation kills the outer most cells of the tumor, it can shed tumor specific peptides/antigens that are picked up and display on the DCs. It can also get the cells to secrete HMGB-1 which binds to the TLR4 and activates the macrophages which in turn secrete IL-12 and other cytokines and chemoattractants to get the right immune response.
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Dr. Rosenberg uses whole body radiation prior to the adoptive cell therapy. He has seen higher responses.
The Immune System needs three Signals:
The role of the CD8+ T cells is to monitor all the cells of the body, ready to destroy any that express foreign antigen fragments in their class I molecules.
Three major events must occur to Activate CD8+ T cell mediated response against melanoma.
First, the T-cell receptor (TRC) must be triggered by a (or multiple) self antigen–derived peptide MHC class I complex. This event depends entirely on appropriate antigen presentation, which is most efficiently provided by mature dendritic cells. 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, 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.
Without the tumor derived debris(Tumor-specific antigens), the immune system doesn't know what to go after.No Immune response will occur.
new-melanoma-treatment-a-turning-point-against-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
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