Accumulation of donor-specific cytotoxic T cells in intestinal lymphoid tissues following intestinal transplantation.

Utilizing a rat model of semiallogeneic intestinal transplantation, recipients were evaluated for accumulation of donor-specific cytotoxic T cells in spleen, mesenteric lymph nodes, Peyer's patches, lamina propria, and intraepithelial lymphocytes using limiting dilution analysis. Naive animals exhibited a low frequency of cytotoxic T cells in spleen and mesenteric lymph nodes with minimal activity detected in Peyer's patches and intraepithelial lymphocytes, but not detectable activity in lamina propria. Orthotopic intestinal transplantation resulted in significant increases in cytotoxic T-cell activity in recipient Peyer's patches as early as Day 6 and by Day 8 in spleen, mesenteric lymph nodes, lamina propria and intraepithelial lymphocyte populations. Graft lamina propria and intraepithelial lymphocytes exhibited significant cytotoxic T-cell activity as early as 4 days following transplant. The highest donor-specific cytotoxic T-cell activity was observed in graft intraepithelial lymphocytes on Day 8 posttransplant. These studies demonstrate rapid expansion of donor-specific cytotoxic T cells which migrate to the graft site within 4 days after semiallogeneic intestinal transplantation.