Two Cells, One Antibody: The Discovery of the Cellular Origins and Transport of Secretory IgA

Secretory Abs of the IgA and IgM isotypes are the foot soldiers of the mucosal immune system, serving as the first line of specific immunity against inhaled, ingested, and sexually transmitted Ags. Adult humans transport some 3 g/d of secretory (SIgA) into external secretions, more than the daily