Humoral and cell-mediated immunity in rats with enhanced kidney allografts.

Abstract

Humoral and cell-mediated immune responses of AS rats transplanted with (AS × August) F1 kidneys were studied. Rats receiving kidney allografts showed a biphasic cytotoxic antibody response, the first peak being 2-mercaptoethanol-sensitive and the second peak being resistant. If enhancing antibody was injected at operation, the first peak of antibody was markedly inhibited and the second peak was moderately inhibited. Cell-mediated immunity was measured by specific release of 51Cr from (AS × August)F1 target cells in short-term culture with peritoneal exudate lymphocytes from grafted rats. Rats receiving kidney allografts showed a response first detected on the 5th day, rising to a peak on the 8th day and then subsiding. Injection of enhancing antiserum caused an apparent delay of 3–4 days in the response, but the intensity of the response was not significantly affected. Intraperitoneal challenge of rats bearing long surviving enhanced kidneys with lymphoid cells from hybrids of the kidney donor genotype provoked a very strong cell-mediated response, and a weak 2-mercaptoethanol-sensitive antibody response. Despite antigenic challenge, the allografted kidneys continued to function. It is proposed that enhancing antiserum causes a delay of the cell-mediated immune response concomi-tantly with an inhibition of IgM synthesis during the induction phase of allograft enhancement. Meanwhile, factors develop which exert an efferent blocking of cell-mediated immunity during the established state of enhancement.