Innate immune regulation of secretory IgA responses

Abstract

Owing to its unique biological function, the gastrointestinal tract (GIT) is constitutively exposed to a plethora of antigens including those of dietary and environmental origin. In addition, the enormous bacterial burden to which these surfaces are exposed necessitates the existence of an integrated immune system capable of deciphering innocuous antigens from potential pathogens in order to maintain homeostasis and preserve the sterility of the mucosal, sub-epithelial layers. Key to this function are secretory immunoglobulins (S-Igs), particularly S-IgA which is the most abundant antibody isotype found at the mucosae. Evidence for the importance of this molecule in facilitating optimal GIT immunity comes from clinical reports of IgA-deficient patients, many of whom experience recurrent mucosal infections. Moreover, S-lgA is essential for immunity to several enteric pathogens including. Enterotoxigenic Escherichia coli, Vibrio cholera and Rotavirus ...