INTERACTION OF ANTIGENS AND ANTIBODIES AT MUCOSAL SURFACES

Abstract

▪ Abstract Infections often involve the mucosal surfaces of the body, which form a boundary with the outside world. This review focuses on immunoglobulin A (IgA) antibodies because IgA is the principal mucosal antibody class. IgA is synthesized by local plasma cells and has a specific polymeric immunoglobulin receptor-mediated transport mechanism for entry into the secretions. By serving as an external barrier capable of inhibiting attachment of microbes to the luminal surface of the mucosal epithelial lining, IgA antibodies form the first line of immune defense. In addition to this traditional mode of extracellular antibody function, recent evidence suggests that IgA antibodies can also function in a nontraditional fashion by neutralizing viruses intracellularly, if a virus is infecting an epithelial cell through which specific IgA antibody is passing on its way to the secretions. IgA antibodies are also envisaged as providing an internal mucosal barrier beneath the mucosal lining. Antigens intercepted b...