Phenotype, immunological reactivity and cytokine production profile of Peyer's patch cells from mice immunized orally with allogeneic cells

Mice of inbred strain BALB/c were immunized orally for LO consecutive days with fresh spleen cells from allogeneic C57BL/10 (B10) donors. The immunize d mice displayed significant allotransplantation immunity ill vivo as demon strated by resistance to the growth of allogeneic tumours induced by high d oses of tumour cells, No significant changes in the proportion of the major T cell subsets in PP of immunized mice were found 1 or 7 days after the la st immunization dose, However, PP cells from orally immunized mice displaye d stronger proliferative response after stimulation with cells used for ora l immunization than the cells from control animals. Similarly, after stimul ation in vitro with specific alloantigens, PP cells from orally immunized m ice produced more IFN-gamma than the cells from control recipients. On the contrary, the production of IL-4 was significantly decreased in the immuniz ed mice. The production of IL-2 by PP cells after oral immunization was not significantly changed and IL-10 was only slightly increased. The results t hus show that oral immunization with allogeneic cells induces systemic tran splantation immunity which can be demonstrated already in Peyer's patches b y increased cell proliferation after immunization with specific alloantigen s and by changes in cytokine production.