title: Limiting dilution analysis of alloreactive cytotoxic precursor cells in aging mice.
abstract: The quantitative minimal estimate of the frequency of alloantigen specific cytotoxic T lymphocyte precursor cells (CTL-p) was determined in young and old C57BL/6 mice by limiting dilution analysis. Supernatant from phorbol myristate acetate-induced EL-4 cells was used as a source of IL 2 in these assays, which therefore were independent of the presence of the Lyt-2-, IL 2-producing cells known to be deficient in aging mice. These studies showed that 24-mo-old mice had approximately 10-fold fewer CTL-p than their young counterparts. Comparison of the limiting dilution assay (LDA) with IL 2-supplemented primary MLC shows that estimates of the frequency of CTL-p do not consistently agree with cytotoxic activity detected in the higher cell density primary MLC, and that the LDA is most likely a better estimate of the effect of age on the development of CTL.
mesh_terms: D000375:Aging; D000818:Animals; D002452:Cell Count; D003601:Cytotoxicity Tests, Immunologic / Q000379:methods; D005260:Female; D007519:Isoantigens / Q000276:immunology*; D008213:Lymphocyte Activation; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013154:Spleen / Q000166:cytology; D013234:Stem Cells / Q000276:immunology*; D013602:T-Lymphocytes, Cytotoxic / Q000166:cytology* / Q000276:immunology
chemical_list: D007519:Isoantigens