In vitro preferential effect of irradiation on cultured T lymphoid cell line.

Abstract

The present report describes a comparative study of cytocidal effect of irradiation on human cultured T and B lymphoid cells. Cytocidal effect of irradiation was expressed as percentage inhibition or percentage reduction, which was calculated by comparing the [3H]thymidine incorporations or viable cell counts in irradiated and unirradiated cultures, respectively. A higher percentage inhibition was observed in each and every T-cell culture, irradiated with 100–4000 rads at days 1–4 of incubation. The most significant difference of percentage inhibition between T and B cells (P<0·05–P<0·01) was observed at each irradiation dose level at day 3. A significant percentage reduction of viable T cells (98–100%) was noted at 100 rad dose level, whereas only 0–3% of B lymphoid cells were killed by this dose of irradiation at days 2–4 of incubation. Our data clearly indicate that human cultured T lymphoid cells are extremely radiosensitive and B lymphoid cells, on the other hand, are fairly radioresistant.