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Julia Julia
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11 years ago
a. they do not display class I MHC  molecules
b. they display fragments of tumor antigen in their MHC molecules
c. they display cancerous viral fragments in the class II MHC molecules
d. they have abnormal amounts of polysaccharides in their extracellular matrix that trigger a T-independent immune response
e. they undergo opsonization by complement proteins so that they are recognized by phagocytes
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wrote...
11 years ago
Check out this link and see if it helps you any... good luck...


http://www.cehs.siu.edu/fix/medmicro/mhc.htm

This might help too....

The expression of products encoded by the major histocompatibility complex (MHC) on tumor cells has recently been studied extensively. It has been found that many malignant tumor cells have their MHC antigens switched-off but that these antigens are re-expressed following DNA-mediated gene transfer, with increased tumor immunogenicity as a result and the consequence that these transformed tumor cells are rejected in vivo

Im really thinking B is correct but I am not %100 sure.
wrote...
11 years ago
It's a tough call, but I think that your best answer is (b.) they display fragments of tumor antigen in the MHC molecules.

The reason I say that is because one of the characteristics of cancer immunology is that the cancer cell does not fully express certain cancer related antigens on its cell surface membrane; thus, the host immune system doesn't always "see" these antigens in order to respond to them.

(c.) looks pretty good but most mammalian cancers are not the result of viral infection; thus, viral fragments would not be there to express.

Most tumor antigens expressed in mammals are going to be of an embryonic nature. For example, "(Other kinds of tumor cells display cell surface receptors that are rare or absent on the surfaces of healthy cells, and which are responsible for activating cellular signal transduction pathways that cause the unregulated growth and division of the tumor cell. Examples include ErbB2, a constitutively active cell surface receptor that is produced at abnormally high levels on  the surface of breast cancer tumor cells.")

Because of the dedifferentiation of cancer cells and the expression of embryonic developmental genes, they tend to create a lot of the protein enzyme telomerase---not found in normal differentiated stable somatic cells.  One would think that they could develop and use antibodies against the protein telomerase for targeting tumor cells for destruction by the host immune system.

See: http://www.oralcancerfoundation.org/treatment/targeted_therapies.htm
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