MAJOR HISTOCOMPATIBILITY COMPLEX

MAJOR HISTOCOMPATIBILITY COMPLEX

A. In transplantation studies, MHC gene products were identified as responsible for graft

rejection. Likewise, studies on responses to antigens, demonstrated thatMHCgene products

were found to control immune responses. It was determined that antigen-specific T cells

recognize portions of protein antigens that are bound noncovalently to MHC gene products.

B. The Major histocompatibility complex is found on human chromosome 6.

1. Have a role in intercellular recognition and discrimination of self/nonself.

2. Have a role in development of humoral and cell-mediated immune responses.

3. One’s set of MHC genes influences the repertoire of antigens to which that person’s TH

and TC cells can respond, therefore, one’s MHC plays a role in susceptibility to disease

and autoimmunity.

C. Organization of MHC is summarized in Table 5–4.

1. Class I MHC are glycoproteins found on most nucleated cells. Class I molecules

present antigenic peptides to the TC.

2. Class II MHC are glycoproteins found on antigen presenting cells (APC).

3. Class III MHC consists of secreted proteins with immune function.

4. Inheritance

a. MHC alleles are inherited as two sets. One set from each parent.

b. One set is the haplotype.