title: Why do class I MHC molecules bind smaller peptides than class II MHC molecules?
abstract: This article attempts to assemble theoretical-teleological argument to explore possible answers to the question of why class I MHC molecules bind smaller peptides than class II MHC molecules and the associated question of why the size of peptides binding to class I molecules is approaching the limit of the self-non-self discrimination. I propose that the small size of most class I-binding peptides precludes the production of 'MHC-restricted' antibodies. Such a strategy avoids the possibility of antibodies binding to the epitopes recognized by CD8+ T cells, thus blocking effector function required for clearance of potentially lethal infections.
authors.affiliation: Division of Cell Biology, John Curtin School of Medical Research, Canberra, Australia Capital Territory.
authors.forename: R V
authors.initials: RV
authors.lastname: Blanden
mesh_terms: D000818:Animals; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D000949:Histocompatibility Antigens Class II / Q000378:metabolism*; D010455:Peptides / Q000737:chemistry* / Q000276:immunology*; D011485:Protein Binding / Q000276:immunology
chemical_list: D015395:Histocompatibility Antigens Class I; D000949:Histocompatibility Antigens Class II; D010455:Peptides