Immunology Flashcards
What are tumor specific antigens?
Antigens expressed on tumor cells but not on normal cells.
What are tumor associated antigens?
Antigens expressed on tumor cells, but also found on normal cells, often in smaller amounts
What is the difference between leukemia and lymphoma and myeloma?
Leukemias are cancers of circulating immune cells, lymphomas are solid lymphoid tumors, myelomas are tumors of plasma cells in the bone marrow.
What is malignant transformation?
When a cell has mutated such that it has become cancerous.
What are proto-oncogenes?
Genes that normally contribute positively to the initiation and execution of cell division.
What are oncogenes?
Mutant formas of proto-oncogenes that contribute to malignant transformation.
What are tumor suppressor genes?
Genes that encode for proteins that prevent the unwanted proliferation of mutant cells.
What are mutagens?
Chemical or physical agents that damage DNA in such a way as to cause an increased rate of mutations.
What are carcinogens?
Mutagens that are known to increase the risk of cancer.
What are oncogenic viruses?
Viruses that have the potential to transform cells and promote tumor formation.
What are common characteristics of cancer cells?
- Stimulate their own growth
- Ignore growth-inhibiting signals
- Avoid death by apoptosis
- Develop blood supply: angiogenesis
- Leave their site of origin to invade other tissues: metastasis
- Replicate continuously to expand their numbers
- Evade or outrun the immune response
What is immunosurveillance?
The ability of the immune system to detect and eliminate tumors at an early stage
What are alloantigens?
Antigens that differs between members of the same species, such as HLA molecules. Alloantigens are recognized as foreign and elicit adaptive immune responses to eradicate the antigen.
How are novel tumor antigens created?
Because tumor specific proteins are not normally created by the cell, when they are spliced and presented by HLA molecules they are recognized as foreign.
How are tumor cells that have low expression of tumor specific antigens able to evade the immune response?
As the cancer develops, the tumor cells with low tumor specific antigens are selected, and continue to be able to avoid detection by CTLs.