Memory T cells from KLH-primed donors do not cause GVHD. Donor C57BL/6 mice were first immunized with KLH antigens. More than 4 weeks later, T cells were obtained from these mice and were sorted into different T-cell subsets. Responses against KLH antigens and alloantigens were evaluated by in vitro proliferation assays and in vivo GVHD assay (C57BL/6→BALB/c). Proliferation was detected by 3H-thymidine incorporation after 5 days in culture. Proliferation assays have been repeated twice with similar results. GVHD data were from a single experiment. (A) Proliferation against KLH antigens. Results represent mean ± SD of triplicate wells. (B) Proliferation against alloantigens. Results represent mean ± SD of triplicate wells. (C) Survival in GVHD assay. P < .05 (memory versus bulk or naive). (D) Weight curve in GVHD assay. Data are represented as mean + SD. P < .05 (memory versus other groups after day 21). TCD BM indicates T-cell–depleted BM. KLH indicates keyhole limpet hemocyanin. *P < .05, memory versus other groups; #P < .05, naive versus bulk.
