[Molecular mechanisms of cellular interaction in immune regulation of hematopoiesis].

Studies are reviewed, which establish a novel regulatory role for the T cell lymphokine IL2: Immunoregulation of hematopoiesis. IL2 induces a receptor-specific inhibition of early erythroid progenitors. IL2-induced inhibition of erythropoiesis is mediated by Interferon-gamma protein release preceded by Interferon-gamma mRNA accumulation. Triggering of the antigen receptor complex induces p55 IL2 receptor expression, which is a prerequisite for IL2-induced erythropoietic inhibition. P55 protein expression on the T cell surface is preceded by an increase of p55 mRNA levels. The studies demonstrate that the regulatory role of IL2 extends beyond governance of the immune system itself and can subserve to control red cell production in vitro.