Sufficiency of the CD8+ T cell lineage to mount an effective tumoricidal response to syngeneic tumor-bearing novel class I MHC antigens.
The origins of "help" in rejection of syngeneic tumors by the CD8 T cell lineage was examined with a model tumor inappropriately expressing novel class I MHC and subject to cytolytic T cell (CTL)-mediated rejection. The requirement for CD4+ Th cells to induce CD8+ CTL effectors in vivo was investigated by using C3H mice selectively depleted of either CD4+ or CD8+ T cells. Rejection of the tumor was vigorous and indistinguishable from normal mice after depletion of CD4+ T cells in vivo. In contrast, in CD8+ T cell-depleted mice tumors grew progressively, confirming that T cells of the CD8+ lineage are required for a tumoricidal immune response, and cells of this lineage are sufficient for a primary response. Taken together, these results demonstrate that, in the absence of CD4+ T cells in vivo, unprimed cells of the CD8+ lineage are fully competent to mount an effective CTL immune response to syngeneic cells expressing novel class I Ag, consistent with the concept that only T cells with class I recognition specificity may be required to satisfy the need for both help and effector functions in the response.
Fan
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Department of Immunology, Research Institute of Scripps Clinic, La Jolla, CA 92037.
Edgington
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D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D002455:Cell Division; D005354:Fibrosarcoma / Q000276:immunology* / Q000473:pathology; D015395:Histocompatibility Antigens Class I / Q000276:immunology*; D007376:Interleukin-2 / Q000502:physiology; D008213:Lymphocyte Activation; D008212:Lymphocyte Depletion; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D010641:Phenotype; D012513:Sarcoma, Experimental / Q000276:immunology* / Q000473:pathology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D006377:T-Lymphocytes, Helper-Inducer / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte; D016827:CD8 Antigens; D015395:Histocompatibility Antigens Class I; D007376:Interleukin-2