title: Characterization of erythroid cell-derived natural suppressor activity.
abstract: Nucleated erythroid cells (NEC) have been previously reported to the capable of suppressing antibody-mediated primary (IgM) and secondary (IgG) immune responses to thymus-dependent antigens. In the present study we indicated that NEC, separated from the spleens of mice following phenylhydrazine treatment were able to suppress directly the proliferative response of preactivated B cells to lipopolysaccharide (LPS) in vitro. While being active in suppressing B cell blastogenesis, NEC, however, failed to reduce both cell proliferation and cytotoxic T lymphocyte (CTL) generation in an allogeneic mixed lymphocyte culture (MLC). NEC also lacked a significant effect on interleukin (IL)-2 production and utilization by concanavalin A (Con A)-activated T lymphocytes. The NEC-derived suppression of B cell proliferation was, at least in part, mediated by soluble molecules. The specific blockade of transforming growth factor (TGF)-beta synthesis with antisense oligodeoxynucleotides (OD) binding TGF-beta mRNA, as well as the neutralization of TGF-beta activity with anti-TGF-beta antibodies (Ab), resulted in a detectable diminished ability of the NEC-conditioned medium (CM) to suppress B cell blastogenesis. Taken together, the results suggest that: 1) NEC may suppress directly B cell responses, while not affecting T cell ones; 2) NEC may mediate their natural suppressor (NS) activity partially through releasing TGF-beta.
authors.affiliation: Department of Experimental Immunology, Institute of Clinical Immunology, Novosibirsk, Russia.
authors.forename: V I
authors.initials: VI
authors.lastname: Seledtsov
authors.forename: G V
authors.initials: GV
authors.lastname: Seledtsova
authors.forename: D M
authors.initials: DM
authors.lastname: Samarin
authors.forename: V Y
authors.initials: VY
authors.lastname: Taraban
authors.forename: S V
authors.initials: SV
authors.lastname: Sennikov
authors.forename: V A
authors.initials: VA
authors.lastname: Kozlov
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000276:immunology / Q000502:physiology; D015672:Erythroid Precursor Cells / Q000276:immunology*; D007155:Immunologic Factors; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D013601:T-Lymphocytes / Q000276:immunology / Q000502:physiology; D016212:Transforming Growth Factor beta / Q000276:immunology / Q000502:physiology
chemical_list: D007155:Immunologic Factors; D016212:Transforming Growth Factor beta