QUANTITATIVE STUDY OF RADIATION EFFECTS IN PHYTOHAEMAGGLUTININ-STIMULATED LEUKOCYTE CULTURES

Effects of x-irradiation (up to 1500 R) have been quantitatively studied in human peripheral blood leukocyte cultures, with and without PHA stimulation, by electronic enumeration and sizing of cell nuclei. Without PHA a dose-dependent reduction of lymphocytes was seen, which was less marked than that resulting from in vivo irradiation. In studying the differential effect of irradiation on blast forms and cell division in PHA-stimulated cultures, vinblastine sulphate was used to arrest cell division. A dose-dependent effect was noted on both blast formation and cell division, but the effect on cell division was much greater. Cultures irradiated after blastogenesis had occurred also showed that the blast forms were not nearly so much affected as was further cell division. Labelling with tritiated cytidine in both irradiated and unirradiated cultures resulted in blast forms that were more heavily labelled than the non-transformed cells. This suggested that the metabolically more active cells were the ones responding to PHA and might be less radiosensitive. On the other hand radiosensitivity as reflected by diminished cell proliferation was pronounced in these cultures. The action of PHA on blastogenesis was discussed in relationship to metabolic alteration of the cell in preparation for cell division. © 1969 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.