Regulation of in vitro erythropoiesis by normal T cells: evidence for two T-cell subsets with opposing function

Cellular interactions responsible for regulating in vitro erythropoiesis were studied using murine monoclonal antibodies recognizing antigens expressed by human mononuclear cells. Cell populations of interest were negatively selected by complement- dependent cytotoxicity and then evaluated for their effect on in vitro growth of erythroid burst-forming units (BFU-E). The data suggest that normal peripheral blood T cells contain at least two functionally distinct subpopulations with opposing regulatory effects: one that enhances burst formation had one that limits burst formation. Whether these effects are mediated by direct interactions of T cells with BFU-E or with auxillary cells remains to be determined.