Tumor cells to immune system suppression (a) a large number of secreted soluble immunosuppressive molecules reported in the literature, tumor immune serum contains a variety of inhibitory molecules, from the non-specific inhibition of acute phase reactive substances to block cell interactions or apoptosis adhesion molecules, cytokines, etc., making the tumor antigen and non-tumor antigen immune response were inhibited, leading to tumor metastasis.
Many tumor cells secrete immunosuppressive cytokines, and some can directly stimulate the growth of certain tumor cells, and some can inhibit a range of immune response, cytokine production, antigen presentation, lymphokine-activated killer cells in cells cytotoxic activity and so contribute to tumor escape from host immune response.
Tumor cells to immune system suppression (b) tumor-infiltrating lymphocytes induced by non-reactive
lT cells induced immune tolerance induction according to the central mechanism for tumor induction of the most direct evidence of immune reaction element should be rendered protein secreted by tumor cells in the thymus, leading to a new generation of T cell clones deleted. Another mechanism is the specific peripheral T cell clones deleted the following several ways dependent.
(1) Fas / FasL pathway
(2) TRAIL-mediated apoptosis
(3) tumor-associated antigen-mediated apoptosis
2.T cell anergy induction
Incapable of inducing T cell response is an important mechanism of tumor escape.
Tumor cells to immune system suppression (c) the induction of suppressor cells
At present, people gradually realized that CD4 + CD25 + regulatory T cells in immune tolerance play an important role in many aspects, and hence the role of cells in tumors have also been concerns. It can be through the release of soluble TCR, soluble IL-2 receptor and immunosuppressive factors (such as TGF-_, IL-I0, etc.) inhibit anti-tumor immunity. Reported in the literature, the tumor can damage animal models injected with CD25mAb CD4 + CD25 + cells and inhibit tumor progression. If you remove the "natural" activation of CD4 + CD25 + cells, most of the mouse model of tumor-free reaction condition is discharged, the remaining CD4 + CD25 cells by autologous APCs for a presentation of MHC n a section of their skin but the proliferation of activated complexes , suggesting tolerance to self antigens, including tumor to be broken.
Tumor cells to immune system suppression (d) signal transduction molecule expression in
Study found that tumor cells can induce T cell activity of the skin, Pat-chain intracellular degradation; also secrete soluble factors eg. ZIP (chain inhibitory protein), adjust the chain at the mRNA level; another is a possible factor in immune exhaustion, chronic long-term tumor antigen TCR stimulation led to sustained activation of complex, processing, chain of self-renewal exhaustion.
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