Sorted CFSEbright CD25-NA cells retain immune responsiveness. Sorted NA cells were derived from DC-stimulated MLRs. These NA cells were also tested for retained immune reactivity, simultaneously with assessments of depletion of alloreactivity. (A) NA cells (104) were cultured with 105 irradiated MNCs from a third-party donor for 8 days. The NA cells mounted a significant MLR (NA-Third Party), roughly equivalent to a primary MLR of fresh CD4+ T cells versus same-donor PBMCs. These same NA cells did not mount a secondary MLR (NA-Restim). Results are representative of 4 experiments. (B) Proliferative responses to Candida and CMV antigens were preserved. Fresh CD4+ T cells (105) and 105 sorted NA cells were stimulated with aliquots of the same frozen/thawed APC population (autologous irradiated CD4-depleted PBMCs). Cultures were pulsed with 3 H-Thymidine on day 7. Results are compared with the alloresponses and depleted alloresponses of the same populations of cells. Results are representative of 3 experiments. Error bars indicate 1 standard deviation from the mean.
