Persistent Antigens Hypothesis: The Human Leukocyte Antigen Connection
Human Leukocyte Antigengenes code for glycoproteins that exist on the surface of most cells in order to facilitate immune surveillance and initiate an immune response to eliminate foreign antigens. There are two main classes of
HLA(Class I and Class II) that support the elimination of cytosolic or extracellular foreign antigens through cell destruction and antibody production, respectively.
HLAgenes have evolved to be the most highly polymorphic in the human genome, thereby maximizing species resistance to foreign antigens and promoting survival. Nonetheless, successful elimination of foreign antigens is predicated on a match between one's
HLAand epitopes derived from foreign antigen proteins. Each person has a limited repertoire of
HLAproteins inherited in a Mendelian fashion for each class. Fortunately, each
HLAprotein can match with various epitopes and, since everyone has one or two alleles at each of the classical loci (Class I
HLA-A, B, and C and Class II
HLA-DP, DQ, and DR), a large number of antigens can be effectively eliminated.