The role of Peyer's patch cells in antibody formation.

The role of Peyer's patches in primary and secondary immune response was studied with as the antigen. E1 Tor ME 7 is a typical enteric antigen which was shown to be suitable for the demonstration of antibody forming cells by localized lysis in agar. No plaque-forming cells (PFC) against this antigen were found in the organs of non-immunized mice. Consequently a primary immune response could be studied. an immune response against this antigen could only be obtained with spleen cells when the donor animal had been primed. After primary intraperitoneal or enteral immunization many PFC were found in the spleen but none in Peyer's patches. This cannot be explained by insufficient penetration of the antigen into Peyer's patches as secondary responses were obtained with both routes of immunization. After local injection of antigen directly into Peyer's patches, PFC only appeared after 5 days. This is an indication that an essential cell type for the immune response is lacking in Peyer's patches. The cells from Peyer's patches were unable to restore the immune response in lethally irradiated mice, unless they were injected together with thymus cells or cells from peripheral lymph nodes. This suggests the absence of active T cells and indicates the presence of B cells in Peyer's patches. The combination of thymus cells and bone marrow cells was inactive in restoring the immune response. This is an indication that the B cells in Peyer's patches are immunologically more mature than bone marrow cells.