| Abstract: | Cell transfer experiments in congenic chick strains, one of which expresses the ov antigen marker, indicate that intestinal γ δ T cells are derived from γ δ + thymocytes in embryos and newly hatched birds, and this early intestinal colonization occurs in two discrete waves. Here, we extend these studies to show that splenic colonization by γ δ T cells occurs in essentially the same way. Following the engraftment of ov+ thymic lobes in thymectomized ov? recipients, γ δ T cells migrate both to the spleen and intestine. By 1 week after hatching, a third generation of thymus-derived γ δ T cells begins to migrate to both peripheral lymphoid organs, and this thymus-dependent seeding process is sustained over the first weeks of life. The survival time for splenic γ δ migrants is significantly less than for the intestinal migrants. Tissue section analysis indicates that γ δ T cells enter the intestinal epithelium at all villus levels. A shift in the γ δ intraepithelial lymphocyte distribution toward the villus tip in thymectomized birds suggests the comigration of enterocytes and γ δ intraepithelial lymphocytes. However, survival kinetics of the donor γ δ population and a relatively high division rate of intestinal γ δ T cells indicate that founder thymic migrants produce relatively long-lived clones of intestinal γ δ T cells. |
