Immunity to Tumors Flashcards
cancer/testis antigens
products of genes that are silent in most normal tissues but are expressed in gametes and trophoblasts and in many types of cancers (melanomas and many carcinogens)
-they are not mutated
oncogenic (causing the development of tumor) viruses
-ex. HPV
the products of these viruses function as tumor antigens and elicit specific T cell responses that may serve to eradicate the tumors
-viral proteins can be processed and presented by MHC molecules on the tumor cell surface
Oncofetal tumor Antigens
proteins that are expressed at high levels in cancer cells and in normal developing fetal but not adult tissues
- antigens that are identified with antibodies raised in other species
- provide markers that aid in tumor diagnosis
- CEA and alpha-fetoprotein (AFP) are the most common and their presence may indicate the association of a tumor
- Most likely passenger mutations
Altered glycoprotein tumor antigens
most human tumors express higher than normal levels of glycoproteins and glycolipids which may be diagnostic markers and targets for therapy
ex. mucin glycoproteins such as MUC-1 are expressed on breast and colon carcinomas
- Most likely passenger mutations
immune score for cancers to assess prognosis and direct treatment options.
The demonstration that the numbers of different types of T cells within resected tumors correlates with the likelihood of metastatic disease has led to the practice of determining an immune score
NK cell role in immune response to tumors
NK cells kill many types of tumor cells, esp. cells that have reduced class 1 MHC expression and express ligands for NK cell-activating receptors
- > Direct killing
- > Recognize downregulation of MHC Class I
Macrophage role in immune response to tumors
Are capable of both inhibiting and promoting the growth and spread of cancers, depending on their activation state
- classically activated M1 macrophages can kill many tumor cells
- Stimulated by IFN-gamma produced by tumor-specific T cells
