title: The blood group antigen-related glycoepitopes: key structural determinants in immunogenesis and AIDS pathogenesis.
abstract: This overview will focus on the functional and pathophysiological aspects of blood group antigen (BGA)-related glycodeterminants with regard to immunogenesis and AIDS pathogenesis. It has been postulated that in a broad range of histogenetically different tissues and organs, BGA-related glycoepitopes are expressed on the cell surface at definite stages of cell differentiation. These glycoepitopes are expressed during embryogenesis, organogenesis, tissue repair, regeneration, remodelling and maturation when 'sorting-out' of one homotypic cell population from a heterotypic assemblage of cells occurs (1). In this event, the BGA-related glycoepitopes, if being expressed on the cell surface, play roles of key structural determinants in cell-cell recognition, association and aggregation. This mechanism will be discussed in relation to immunogenesis with regard to antigen presentation, self-non-self discrimination, and positive and negative selection during thymic education. It is postulated that the appearance of BGA-related glycoepitopes on the cell membrane is a consequence of the association of major histocompatibility complex antigens (MHC) and peptides, with the subsequent elimination of cells carrying a high density of BGA-related glycoepitopes on their surface. After human immunodeficiency virus (HIV) glycoproteins are glycosylated by host cell glycosyltransferases, the virus may use the BGA-related glycodeterminants as ligands and/or receptors for expansion to a spectrum of target cells during AIDS development and generalization of the infection throughout the body. We will review the experimental evidence that supports the concept that HIV uses an alternative to the gp120/CD4 ligand/receptor system, and that the alternative mechanism is probably carbohydrate-mediated in nature.
mesh_terms: D000163:Acquired Immunodeficiency Syndrome / Q000209:etiology* / Q000276:immunology / Q000628:therapy; D001789:Blood Group Antigens / Q000276:immunology*; D002241:Carbohydrates / Q000276:immunology; D002449:Cell Aggregation / Q000276:immunology; D002454:Cell Differentiation / Q000276:immunology; D005314:Embryonic and Fetal Development / Q000276:immunology; D000939:Epitopes; D006801:Humans; D007109:Immunity; D009369:Neoplasms / Q000628:therapy; D014612:Vaccines / Q000302:isolation & purification
chemical_list: D001789:Blood Group Antigens; D002241:Carbohydrates; D000939:Epitopes; D014612:Vaccines