DELAYED-TYPE HYPERSENSITIVITY RESPONSES IN MICE TRANSPLANTED WITH RATHEPATOCYTES

The delayed type hypersensitivity (DTH) response to xenogeneic hepatoc ytes (HCs) was investigated in mice received subcutaneous (s.c.), intr asplenic (i.s.), or intravenous (i.v.) transplantation of rat HCs. The DTH response in mice preimmunized i.s. or i.v. with rat HCs (1x10(6) cells) was significantly lower than that in mice preimmunized s.c. wit h the same doses of rat HCs. Go-transfer of spleen cells from i.s. imm unized mice with spleen cells from s.c. immunized mice to naive recipi ent mice did not suppress the DTH response induced by transfer of sple en cells from s.c. immunized mice. On the other hand, co-transfer of s pleen cells from i.v. immunized mice with spleen cells from s.c. immun ized mice suppressed the DTH response to rat HCs in recipients. Furthe rmore, the levels of DTH responses in recipients transferred with sple en cells from mice sensitized i.s. or i.v. with rat HCs, immunized s.c . with rat HCs 6 hr after transfer, and challenged with rat HCs 7 days later was almost similar to those in recipients transferred with sple en cells from s.c. immunized mice. These results suggest that antigen- specific suppression of DTH responses to rat HCs in mice is associated with the presence of suppressive spleen cells induced by i.s. or i.v. immunization with rat HCs.