Mucosal IgA elaboration.

Secretory IgA is the main immunoglobulin present along mucosal surfaces. It is elicited best by oral rather than parenteral administration of specific antigens. The role of antigen form on the development of a secretory IgA response is still unclear. IgA protects by preventing attachment of microorganisms or their toxic products to the surface epithelium. A wide variety of regulatory T cells are now known to be of considerable importance in optimizing the secretory IgA response. This regulation is at least partly due to the elaboration of small polypeptide products (lymphokines). These lymphokines have been shown to be key signals during the maturation of IgA precursor B cells to IgA-secreting plasma cells. By studying models of the mucosal immune system which closely approximate the natural mucosal immune response, it should be possible to develop vaccines against many pathogenic microorganisms, their toxic products, and to toxicants and carcinogens within the environment.