Molecular mechanisms of the immunosuppressive effect of erythroid cells.

This review presents data suggesting a new immunoregulatory role of the erythroid nucleus-containing cells. The three main mechanisms of the possible immunosuppressive effect of these cells are described. It has been demonstrated that the erythroid nucleus-containing cells produce a variety of both pro- and anti-inflammatory cytokines. The p15 protein (a product of the env gene) is considered to provide a novel immunosuppressive mechanism. Finally, the existing data suggest that the erythroid nucleus-containing cells are able to produce an immunosuppressive factor, which is different from the known cytokines. It has been proposed that the immunosuppressive effect of the erythroid nucleus-containing cells greatly contributes to the regulation of the immune homeostasis in normal and immunopathological conditions.