Antibody response in C3H mice injected with CBA lymphoid cells as detected by membrane immunofluorescent staining

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.

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.

Partial tolerant state against H-2 disparate cells. No impaired specific reactivity in MLC, GVH, or antibody production

Injection of CBA mice with H-2-compatible lymphoid cells from C3H hybrids induces a specific reduction of the mixed lymphocyte culture (MLC) response of their lymphoytes. This is not the case after injection of H-2-disparate C3H-hybrid cells, presumably because they are rapidly eliminated due to the immune response of the host. This investigation shows that CBA mice injected with CBA X C57Bl cells (H-2-disparate) at an age of 0-3 days, but not older, develop a specifically reduced MLC response after infusion of C3H X C57Bl cells as adults, indicating that they were tolerant to the C57Bl-determined antigens. However, lymphocytes from such mice showed a normal reactivity against C57Bl as assessed by MLC, graft-versus-host tests, and capacity to produce specific antibodies.

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.