Immunology Flashcards
(30 cards)
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.
How do NK and T cells recognize MIC?
NKG2D receptors on NK and T cells allows for the recognition of MIC proteins on the tumor cell surface, which leads to cytotoxic killing of the tumor cells.
How to MIC expressing tumor cells evade NK and T cell detection?
Some variant tumor cells are able to cleave MIC from its cell surface. Soluble MIC then binds NKG2D on lymphocytes and renders the CTL unable to bind other MIC proteins. The variant tumor cell is not killed and survives to proliferate and cause cancer.
How can tumor cells evade MHC mediated CTL killing?
Some tumors downregulate MHC class 1 expression which would normally allow them to be recognized by CTLs. However, tumor cells can evade MHC mediated T cell killing by not expressing the costimulator molecule B7, and the T cell will not be activated. (creates anergic T cells)
How are cytokines involved in tumor induced suppression of the immune system?
-TGFbeta reduces the function of both CD4 and CD8 T cells by inhibiting proliferation and cytokine production of Th1 cells, and it also inhibits lytic granule release and proliferation of cytotoxic T cells.
Tregs limit the function of effector T cell populations by producing anti-inflammatory cytokines like TGFbeta and IL-10.
What are monoclonal antibodies?
Antibodies produced by a single B cell clone and thus are all identical in structure and antigen specificity.
Primary tumor size and location can be determined, as well as the location of possible metastases.
What does Rituximab do?
Monoclonal antibody against CD20 antigen
CD20 functions in B-cell signaling
Used to treat Non-Hodgkin’s lymphoma
What does Trastuzumab do?
Monoclonal antibody against HER2/neu antigen
HER2/new functions as a growth receptor
Treats breast cancer
What does Alemtuzumab do?
Monoclonal antibody against CD52 antigen
CD52 functions as differentiation antigen
Treats chronic lymphocytic leukemia
What does Cetruximab do?
Monoclonal antibody against EGFR antigen
EGFR is a growth actor receptor
Treats colorectal cancer, and head and neck cancer
