Question

Your reply to each of the questions should be 100 words in length. It must be in your own words and remember to cite your sources.

1.     Discuss the specific (adaptive) immune response to tumors

2.     Explain the mechanisms how the tumor cells are able to escape the immune response

Answer 1

1. When tumor are formed and growing in body, the immune system of human body tries to eliminate the tuomr cell from the body. Tumor cells show tumor associated antigens or TAAs which are absent in normal cell. As these TAAs are foreign to body, the immune system thus tries to free the body from those antigens. TAAs are presented by MHC class I or MHC class II antigen presenting cells and are recognized by T cells ( CD8⁺ cytotoxic T cells and CD4⁺ helper T cells). This recognition induces T cell function and several cytokines and chemokines are secreted to destroy the cancer cells. Further clonal expansion of T cell occurs and also other immune cells are get recruited to the site.

Adaptive immunity in cancer immunology and therapeutics, Ecancermedicalscience. 2014; 8: 441.

2.Immune system is functioning to regulate tumor growth and development However, cancer cells are able to escape the immunosurveillance by several mechanism. Such as

i) participation of immunesuppresive regulatory cells like CD4⁺CD25⁺ FoxP3⁺ positive T cells found in tumor microenvironement. Chemokine produced by tumor cells are mostly responsible for the acumulation of immunosuppresive regulatory cells in the microenvironement.

ii) Secondly the functional antigen presentation by MHC pathway also get modified in tumor cells. When the expression is tumor specific antigens are downregulated c<ytotoxic T cells are unable to recongmize them as foreign.

iii) there are several immunesuppresive cytokines likeTNF-?, IL-1, IL-6, IL-8 or IL-10 which are also taking part into tumor growth.

When tumor are formed and growing in body, the immune system of human body tries to eliminate the tuomr cell from the body. Tumor cells show tumor associated antigens or TAAs which are absent in normal cell. As these TAAs are foreign to body, the immune system thus tries to free the body from those antigens. TAAs are presented by MHC class I or MHC class II antigen presenting cells and are recognized by T cells ( CD8⁺ cytotoxic T cells and CD4⁺ helper T cells). This recognition induces T cell function and several cytokines and chemokines are secreted to destroy the cancer cells. Further clonal expansion of T cell occurs and also other immune cells are get recruited to the site.

Adaptive immunity in cancer immunology and therapeutics, Ecancermedicalscience. 2014; 8: 441.

2.Immune system is functioning to regulate tumor growth and development However, cancer cells are able to escape the immunosurveillance by several mechanism. Such as

i) participation of immunesuppresive regulatory cells like CD4⁺CD25⁺ FoxP3⁺ positive T cells found in tumor microenvironement. Chemokine produced by tumor cells are mostly responsible for the acumulation of immunosuppresive regulatory cells in the microenvironement.

ii) Secondly the functional antigen presentation by MHC pathway also get modified in tumor cells. When the expression is tumor specific antigens are downregulated c<ytotoxic T cells are unable to recongmize them as foreign.

iii) there are several immunesuppresive cytokines likeTNF-?, IL-1, IL-6, IL-8 or IL-10 which are also taking part into tumor growth.

Immune evasion in cancer: Mechanistic basis and therapeutic strategies,

Seminars in Cancer Biology

Volume 35, Supplement, December 2015, Pages S185-S198