Effect of cimetidine on burst-promoting activity of normal T lymphocytes.

The effect of cimetidine, an inhibitor of suppressor T lymphocytes, on the burst-promoting activity (BPA) of normal T lymphocytes has been studied. Cimetidine has been shown to increase the BPA of normal T lymphocytes, both when added to the culture and when T lymphocytes were preincubated for 1 h with it. Cimetidine had no direct effect on the in vitro growth of burst-forming units (BFU-E). Our results show that CD8 suppressor T lymphocytes inhibit the in vitro growth of BFU-E in normal conditions, either directly or through inhibition of BPA of CD4 helper T lymphocytes. Cimetidine has proved to be a useful tool for investigating the hematological role of T-lymphocyte subsets in normal and pathological conditions.