Target cell for prostaglandin E in the stimulation of in vitro human erythroid (BFU-E) progenitor cells: correlation of Ia antigen expression with the stimulatory effect.

The role of monocytes, T-lymphocytes, and Ia antigen expression in the mediation of prostaglandin E1 (PGE1) stimulation of in vitro erythroid progenitor cells was studied. Human peripheral blood mononuclear cells were selectively depleted of monocytes or T-lymphocytes. Stimulation of burst formation was noted at PGE1 concentrations of 10(-7) and 10(-8) M in the presence or absence of monocytes or T-lymphocytes in the cultures. The role of Ia antigen expression in the stimulatory response to PGE1 was explored by performing clonogenic assays on monocyte-depleted cells that had been pretreated with complement alone, monoclonal anti-Ia (NEI-011) and complement, or anti-Ia alone. Colony formation was reduced by 50%-89% after treatment with anti-Ia and complement. The stimulatory response to PGE1 was abrogated following anti-Ia-complement treatment, but was preserved following treatment with anti-Ia alone. These results suggest that monocytes and T-lymphocytes are not required for PGE1-induced stimulation of burst formation and that Ia antigen expression correlates with sensitivity to the stimulatory effect of PGE1.