Regulatory Mechanisms in Cell-Mediated Immune Responses

[摘要] Mouse spleen cells which had been primed to alloantigens by in vitro mixed lymphocyte culture (MLC) were found to actively suppress the in vitro generation of cell-mediated cytotoxicity (CML) by freshly explanted syngeneic spleen cells. Both antigen-specific and antigen-nonspecific suppressor activities were identified. Antigen-nonspecific suppression was active in suppressing CML sensitizations to alloantigens, including those to which the suppressor population had not been previously exposed. This form of suppression was radiation sensitive (abrogated by 1000 R). It was T cell dependent, appeared after 2 days of priming in MLC, and was effective in suppressing CML only when added during the first 2 days of sensitization culture. In contrast, antigen-specific suppression affected only those CML snesitizations in which the relevant sensitizing antigen either: 1) was the same antigen to which the suppressor population was previously primed, or 2) was presented on the same cell as that alloantigen. Antigen-specific suppression was resistant to 1000 R. It was T cell-dependent, first appeared after 3 days of priming in MLC, and suppressed CML only when added during the first 2 days of sensitization. These data are discussed in terms of regulatory mechanisms which may be active in determing the kinetics and antigen specificity of primary and secondary CML responses.

[学科分类] 生物科学（综合）