Effect of heat-shock on rhesus monkey lymphocytes and IL-2-dependent cells

Treatment of Rhesus monkey peripheral blood lymphocytes and IL-2 dependent cell lines with heat prior to incubation with mitogens or IL-2, respectively, induces significant cell changes at the nuclear level, detected by DNA staining with Vindelov's propidium iodide and the simultaneous measurement of its red fluorescence and 90 degrees light scatter. These changes are an increase in their nuclear granularity and in apparently fragmented DNA which shows less fluorescence intensity than DNA from nuclei in the G0G1 phase, a phenomenon suggestive of apoptosis. Treated cells also show an increased number of nuclei in G1 or early S phase, with a reduction in those reaching the G2 or M phases. After heat-shock treatment, CTLL-2 cells show an increase in their response to low doses of recombinant IL-2 and an impaired ability to proliferate at higher IL-2 concentrations. These results provide further evidence for the regulatory role of stress-induced events.