Graft-infiltrating cells in rats receiving orthotopic semiallogeneic small intestine transplantation with portal or systemic venous drainage.

ABSTRACT

The effect of alterations in venous drainage, from either ivc to portal vein (pv), along with peritransplant systemic (ivc) or portal (pv) venous alloimmunization with irradiated semiallogenic cells, on cell subset recovery in lymphoid organs of Lewis rats receiving orthoptic small bowel allografts (from LewisXBrown Norway) F1, LBNF1) was examined. Combined portal, venous drainage and alloimmunization has been reported to increase graft/recipient survival in this model. FACS analysis using monoclonal antibodies specific for different lymphocyte subsets was performed on cell suspensions of peripheral (P) and mesenteric (M) lymph node (LN), small bowel intraepithelial lymphocytes (SBIEL), and Peyer's patch (PP) lymphocytes on days 2 and 8 posttransplantation. Donor cell contributions to these cellular analyses were estimated by comparison of FACS staining with polyclonal anti-Lewis or Lewis anti-LBNF1 antibodies. Control animals received syngeneic grafts. In both syngeneic and semi-allogenic transplants with pv or ivc drainage there was no consistent difference in cell subsets from in PLN compared with those of control nongrafted rats. Approximately 50% to 60% of these cells were alphabetaTcR+ with a CD4+/CD8+ ratio of 3-41 and a (CD4++CD8+)/alphabetaTcR+ ratio of 11. Some 5% to 12% ED3+ cells were also present. In IEL, MLN, and PP by contrast, there were significant differences in cells recovered from rats with ivc vs. pv drainage of grafts. The most striking changes reflected a decreased CD4+/CD8+ and alphabetaTcR+gammadeltaTcR+ cells in these tissues in rats predestined to show prolongation of allograft survival (ivc vs. pv injected IEL CD4/CD8+ ratios and alphabetaTcR+gammadeltaTcR+ ratios 1.0, 0.7 and 5.0, 1.0, respectively. These data are consistent with a proposed role for such gammadeltaTcR+ cells in the local regulation of graft rejection.