Prolonged survival of H-2 incompatible skin allografts on F1 animals treated with parental lymphoid cells.

Abstract

The survival times of H-2 incompatible skin allografts were studied in F1 hybrids treated with parental strain lymphoid cells. The injection of 50×106 A/Sn lymphoid cells into A/Sn×CBA F1 hybrids greatly prolonged the survival of 5M skin allografts applied 7 days later. Suppression of allograft rejection was observed also in F1 recipients that were actively or adoptively immunized against the skin graft donor. The immunocompetence of the sensitized F1 hosts was supressed to a greater degree than that of normal non-sensitized recipients. It is unlikely that immuno-incompetence is caused by basic effects of the graft-versus-host reaction or by antigenic competition since overt signs of a graft-versus-host reaction were not a necessary prerequisite for immunosuppression. It is suggested that a general inhibition of expression of immunity develops as a consequence of the immune reaction, possibly mediated by humoral factors.