Migration of B and T lymphocytes to M cells in Peyer's patch follicle epithelium: an autoradiographic and immunocytochemical study in mice.

Intimate interaction occurs between M cells which take up antigens in Peyer's patch epithelium and underlying lymphocytes but the migratory pathway and subtypes of these lymphocytes have remained uncertain. Lymphocyte homing to Peyer's patches was investigated by separating mouse splenic B and T lymphocytes, labeling with [3H]adenosine, reinjecting into syngeneic mice, and localizing them by autoradiography after 17, 40, and 68 hr. Both B and T lymphocytes migrated across postcapillary venules through intercellular spaces. Most labeled cells of both types localized around postcapillary venules in the initial time period, then migrated through the lymphoid mass to follicle epithelium. T-cell number in follicle epithelium peaked at 17 hr but B cells peaked at 40 hr. At each time point more labeled B than T lymphocytes were found below M cells and in follicle epithelium but the differences were only significant (P less than 0.01) at 40 hr. Endogenous B lymphocytes, identified by antibody staining, were also associated with M cells, possibly reflecting a role for secretory antibody in modulating antigen uptake.