Figure 5

Groups of 5 young Rag1-deficient C57BL/6 mice were given either 0.75, 1.5, or 3.0 million, wild-type splenic T cells from 3–4 or 18–20 month old wild type C57BL/6 mice 7 days prior to being challenged with 10 million 5T33L MMM cells. A third group of 12 Rag1-deficient C57BL/6 mice were given no wild type splenic T cells prior to being challenged with 10 million 5T33 MMM cells. Survival of C57BL/6 Rag1-deficient mice given splenic T cells from 3–4 month old mice was significantly greater following challenge with 10 million 5T33L MMM cells than that of C57BL/6 Rag1-deficient mice given T cells from 18–20 month old C57BL/6 1 week prior to challenge with 10 million 5T33L MMM cells (Chi square statistic with Fisher exact test p < 0.017). A significantly greater number (11 of 12) of young Rag1-deficient mice not given any splenic T cells died following challenge with 5T33L MMM cells than young Rag1-deficient mice given splenic T cells from old mice prior to challenge with 5T33 MMM cells. (Chi-square-Fisher exact test, p < 0.019). The inhibitory potency of young splenic T cells compared to old splenic T cells was estimated to be 8 to1.