Acquisition of a multifunctional IgA+ plasma cell phenotype in the gut

IgA secreting plasma cells in the lamina propria are shown to be an important source of iNOS and TNF required to maintain the homeostatic balance between intestinal microbes and the immune system. The gut contains a vast number of bacteria that are essential for the health of the organism, but it is also a rich source of lymphocytes that exist to eliminate infections. How do lymphocytes restrain themselves from attacking beneficial bacteria, yet...