Frequencies of alloreactive and self-restricted cytotoxic T cell precursors during lymphatic regeneration.
The previous observation that during lymphatic regeneration precursors for MHC-restricted cytotoxic T cells appear before alloreactive precursors, was re-examined in macroculture and microculture experiments. Our macroculture experiments confirmed the observation that treatment with cyclophosphamide decreases the ratio of alloreactivity vs self-restricted reactivity. This shift in reactivity, however, did not result from a change in the T cell specificity repertoire, but was obviously mediated by regulatory effects in macrocultures. Spleen cells from cyclophosphamide-treated mice had normal ratios of CTL precursor frequencies for the three different specificities tested, but they contained a suppressive activity that inhibited the responses of normal spleen cells in macrocultures. Note Added: After submission of this paper we became aware of the paper of Sihvola and Hurme (J. Immunol. 130:1077, 1983) who also showed that although macrocultures from cyclophosphamide-treated mice were negative for the alloresponse, the same spleen cells showed only a approximately threefold decrease in CTL precursors when analyzed in limiting dilution cultures.
D000818:Animals; D003520:Cyclophosphamide / Q000494:pharmacology; D008221:Lymphoid Tissue / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D012038:Regeneration; D013154:Spleen / Q000166:cytology / Q000187:drug effects; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology* / Q000276:immunology
D003520:Cyclophosphamide