F1-hybrid anti-parental-strain reactivity. I. Impaired proliferation of CBA lymphocytes in the spleens of irradiated C3H X CBA mice pretreated with CBA spleen cells.

Abstract

Previous investigations have indicated that C3H X CBA hybrid lymphocytes can neutralize lymphocytes which are reactive against the C3H-determined Mls antigen when injected into the H-2-compatible strain CBA. In this study we have inoculated C3H X CBA hybrids with CBA spleen cells and 2 weeks later lethally irradiated the mice and injected them with CBA lymphocytes to study their proliferation in the host spleen. Proliferation of lymphocytes from CBA mice, but not from C57Bl mice, was significantly impaired in such hosts, indicating that the hybrids had become immunized against the parental cells. In contrast, such an effect was not detected by treating CBA X C57Bl mice with CBA spleen cells. Humoral antibodies in the C3H X CBA hybrids capable of blocking the response of CBA lymphocytes against C3H X CBA cells could not be detected, indicating that inhibition of lymphocyte proliferation is cell mediated rather than by humoral factors.