Figure 1.

A subset of IgA+ ASCs acquire and elongated/sickled morphology near the crypt base. A, IgA+ ASCs near the crypt base have an elongated (sickle-like) morphology (cross sections). B, Higher magnification of an adherent cell with sickled morphology. C, Direct cell to cell contact between IEC and sickle cell with extensive RER and IgA immunogold particles (representative TEM image). D, Proposed new model of αEβ7-dependent IgA transcytosis in which αEβ7+ IgA+ ASCs dock with IEC to directly relay dIgA to pIgR for transcytosis into the intestinal lumen, from Guzman et al.⁴²