Erythroid cells in immunoregulation: characterization of a novel suppressor factor.

Nucleated erythroid cells (EC) have been previously reported to possess a potent natural suppressor (NS) activity for B-cell responses. In this study, we demonstrate that murine EC are able to reduce not only lipopolysaccharide (LPS)-driven B-cell proliferation, but also proliferative and cytotoxic T-cell responses generated in a primary allogeneic mixed lymphocyte culture (MLC); and that a soluble low molecular weight factor may be involved in such EC-derived immunoregulation. In addition, the erythroid cell-derived suppressor factor (ESF) was found to be capable of effectively reducing the allergen-driven proliferation of peripheral blood mononuclear cells (PBMC) isolated from allergic patients.

[Effects of multipotent hematopoietic stem cell inhibitory factor on formation of immune response to viral antigen].

An immunostimulating effect of PIF was studied. The augmentation of antibody production to Coxsackie A13 virus as well as protective effect during influenza infection have been found out in mice after PIF injections. An immunostimulating effect of PIF after SRBC immunization of mice has been also revealed.

[Expression of erythroid differentiation antigens on mononuclear cells of peripheral blood in neoplastic progression of non-Hodgkin's malignant lymphoma].

High level expression of erythroid differentiation antigens on peripheral blood mononuclear cells associated with increased BFUe number has been identified in a malignant lymphoma patient. A possible pathogenetic role of such disturbance in leukemogenesis has been considered.

[The regulation of hematopoietic stem cell proliferation and differentiation (CFU-S) during antigenic exposure].

Hemopoietic stem cell (CFUs) proliferation is controlled by regulatory activities (stimulator and inhibitor) produced by bone marrow macrophages. Previously it has been shown that antigen administration stimulates CFUs proliferation. The data obtained in this study show the possible mechanism of antigen-induced stimulation of CFUs proliferation.