Answer:
The major histocompatibility complex is described as
a. a set of glycoproteins, called MHC antigens, found on all body cells.
Explanation:
The histocompatibility complex gene group give instructions for producing a group of related proteins known as the human leukocyte antigen (HLA) complex.
The HLA complex assist the immune system to distinguish the body's own proteins from proteins made by foreign objects like viruses and bacteria.
HLA is the human version of the major histocompatibility complex (MHC), a gene group that occurs in many species.
Humans have MHC complex consisting of more than 200 genes located close together on chromosome 6. Genes in this complex are categorized into three basic groups: class I, class II, and class III.
Humans have three main MHC class I genes, known as HLA-A, HLA-B, and HLA-C. The proteins produced from these genes are present on the surface of almost all cells. On the surface of the cell, these proteins binds to protein fragments (peptides) that have been exported from within the cell. MHC class I proteins display these peptides to the immune system. If the immune system recognizes the peptides as foreign (such as viral or bacterial peptides), it responded by triggering the infected cell to self-destruct.
There are six main MHC class II genes in humans: HLA-DPA1, HLA-DPB1, HLA-DQA1, HLA-DQB1, HLA-DRA, and HLA-DRB1. MHC class II genes provide instructions for making proteins that are present almost exclusively on the surface of certain immune system cells. Like MHC class I proteins, these proteins display peptides to the immune system.
The proteins produced from MHC class III genes are involved in inflammation and other immune system activities. The functions of some MHC genes are still unknown.
