Question

3.1 Discuss the similarities and differences between MHC's and HLA's. Describe the roles of the three MHC classes.

3.2 Describe antigen processing .How does the process differ from endogenous and exogenous antiges? ( 20 marks)

Answer 1

3.1 Similarities: Both MHC (major histocompatibility complex) and HLA (human leukocyte antigen) are antigens that are present on cell surfaces and genetic material of cells. Both of them assist the immune system in recognising invading pathogens and preventing its multiplication within the body. Both regulate the immune system and its immune responses.

Differences: HLA is a gene complex present in humans which encode for MHC molecules (proteins). MHC are the molecules which play a major role in recognition of foreign substances which disrupt the normal functioning of the cells. HLA is present only in humans while MHC molecules are commonly present in vertebrates.

Functions:

MHC class I presents processed endogenous antigen to CD8 T cell.

MHC class II presents process exogenous antigen to CD4 T cell.

MHC class III produces proteins that assist in immune responses, complement proteins and inflammatory cytotkines.