Reduced capacity to produce specific 'effector' cells after injection of CBA mice with C3H cells

Influence of an M-locus difference on the cellular and humoral immunological reactivity against H-2 determined antigens of the mouse

Studies were initiated to determine whether an immune response to the Mls antigen of C3H mice could modify responses of CBA lymphocytes (H-2-compatible) to a foreign H-2 complex. CBA lymphocytes, partially tolerant to the C3H-determined Mls antigen, generated less effector cell activity against C57Bl cells (H-2-incompatible) than lymph node cells from normal CBA donors when infused into irradiated C3H X C57Bl hosts. Effector cell activity was measured as the capacity of the cells in the irradiated spleens to inhibit CBA X C57Bl bone marrow proliferation. In contrast, immunization of CBA mice with C3H X C57Bl cells yielded lower antibody titers against C57Bl cells than immunization with CBA X C57Bl cells. Furthermore, preinjection of CBA mice with C3H X CBA cells strongly reduced the capacity of the animals to produce antibodies against C57Bl cells. Thus, these data support the conclusion that an immune response to a foreign Mls antigen may either enhance or suppress an immune response to H-2-incompatible cells.

Proliferation of C3H x CBA hybrid lymphocytes in the spleens of irradiated CBA mice: linkage to the Mls-gene

Lymphocytes from C3H x CBA F1 mice, lacking detectable Mls-antigens, can specifically inactivate T-cell clones from the H-2-identical strain CBA, which are reactive against the C3H-determined Mls-antigen. Such F1 lymphocytes also proliferate in the spleens of irradiated CBA mice. The age dependence of the mixed lymphocyte culture stimulatory capacity and the capacity to proliferate in irradiated CBA recipients of lymphocytes from C3H x CBA F1 mice were compared. It was observed that appearance of Mls-bearing cells is preceded by the appearance of F1 cells with strong proliferative capacity in irradiated CBA recipients. The in vivo proliferative response is also dependent on the age of the recipient. The varying response is not reflected in the quantity of anti-C3H Mls-reactive cells in CBA mice. A strong linkage between the genes controlling the above proliferative and stimulatory capacities of C3H x CBA lymphocytes was found.

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

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.

F1-hybrid anti-parental-strain reactivity. II. Proliferation of C3H X CBA hybrid lymphocytes in the spleens of irradiated CBA mice

Experiments were conducted to explore whether C3H X CBA lymphocytes can react by proliferation when they meet parental CBA spleen cells. MLC tests could not detect such a reaction, but infusion of C3H X CBA lymph node cells into irradiated CBA hosts resulted in rapid cell proliferation in the host's spleen. Such a cell proliferation was also observed after infusion of T-cell-enriched lymph node cell preparations or thymic cells from C3H X CBA donors. Upon transfer to new irradiated mice these proliferating cells continued to proliferate in CBA mice but not in C3H X CBA mice. Further evidence that the injected T-cells were the proliferating emerged from experiments where AKR X CBA lymphocytes were found to proliferate in spleens of irradiated CBA mice and that most of these cells posessed the theta antigen determined by AKR. Proliferation of F1-hybrid lymphocytes in the spleens of its irradiated parental strains was found not to be a general phenomenon and is probably restricted to some Mls-antigen-compatible strain combinations. The possibility that the C3H X CBA hybrid lymphocytes are stimulated to proliferations by CBA lymphocytes reactive against the C3H-determined Mls antigen is discussed.

Complex nature of the production of 'effector' cells and their interaction with target cells in the M-antigen system of the mouse

The capacity of lymphocytes from mouse strain CBA to generate 'effector' cells against the H-2-compatible, M-antigen-incompatible strain C3H and their interaction with such target cells were investigated. It was observed that CBA lymphocytes injected in, and 5 days later obtained from, the spleens of irradiated C3H X CBA hybrids ('educated cells') could strongly inhibit the growth of C3H X CBA bone marrow cells but were almost nonresponsive to C3H X C57BI bone marrow targets (H-2-incompatible). CBA lymphocytes educated in irradiated C3H X C57BI hosts displayed reactivity against C3H X C57BI and CBA X C57BL but not against C3H X CBA bone marrow target cells. Additional tests indicated that the M antigen determined by C3H is expressed to approximately the same extent on C3H X CBA and C3H X C75BL cells and that the M antigen on C3H does not cross-react immunologically with antigens on C57BL cells. Moreover, it was observed that CBA X C57BI lymphocytes were triggered to cell proliferation by C3H antigens but were unable or had a highly reduced capacity to develop 'effector' cells in response to this antigenic stimulus. These results indicate that generation of 'effector' cells and their interaction with target cells are very complex processes.