| Abstract: | Human lymphocytes were exposed to varying doses of roentgen irradiation in vitro and thereafter tested for reactivity to different polyclonal mitogens and antigens using DNA synthesis as a marker for viability. The dose response profiles obtained indicate that there are two subpopulations of lymphocytes which are responsive to phytohaemagglutinin, poke weed mitogen, concanavalin A and allogeneic cells. One is relatively sensitive to radiation and the other is relatively resistant. However, no "resistant" PPD-tuberculin responsive cell population could be detected. Irradiated lymphocyte populations enriched for T-cells exhibited both a sensitive and a resistant PHA-responsive population, whereas cell populations enriched for B-cells only exhibited a radiation sensitive one. |
