The effect of in vitro irradiation on the responses of human lymphocytes to PHA, PPD and allogeneic cells.

The effect of X-ray, cobalt and 45 MeV electron irradiation on the responses of lymphocytes to PHA, PPD and allogeneic cells was studied using a semimicro lymphocyte culture technique. The responses to PPD and allogeneic cells were found to be more sensitive to irradiation than the response to PHA, even when the time factor was taken into account, i.e. the effect of irradiation was measured on the same day irrespective the type of stimulation. At the doses used, 500, 3000 and 6000 rd, there was no difference between the effects of the three types of radiation used. The possible explanations for the findings are discussed.