title: Erythroid cells in immunoregulation: characterization of a novel suppressor factor.
abstract: 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. From the data presented herein, it appears that ESF is heat-stable (80 degrees C for 20 min) and has molecular weight (MW) lower or close to 0.5 kDa. ESF activity is resistant to both enzyme (trypsin plus chymotrypsin) proteolysis and action of the enzymes such as lipase and phospholipase C. On the other hand, ESF is effectively inactivated by neuraminidase treatment, suggesting the presence in its structure of sialic residue(s). The neuraminidase-sensitive, ESF-like activity is readily detected in the medium conditioned with normal mouse bone marrow (BM) cells. On fractionation of low MW erythroid products on a reversed-phase C16 column in a linear acetonitrile gradient (5-95%), ESF activity is detected in the first peak alone with the shortest time of its retention by the column. The results suggest that (1) by producing ESF, EC may regulate both B- and T-cell-mediated immune processes and (2) based on its physicochemical and biological characteristics, ESF can be distinguished from each of earlier characterised suppressor mediators of bone marrow origin.
authors.affiliation: Department of Immunohematology, Institute of Clinical Immunology, Russian Academy of Medical Sciences, 14 Yadrintsevskaya street, 630099 Novosibirsk, Russia. vs@online.nsk.su
authors.forename: Galina V
authors.initials: GV
authors.lastname: Seledtsova
authors.forename: Victor I
authors.initials: VI
authors.lastname: Seledtsov
authors.forename: Denis M
authors.initials: DM
authors.lastname: Samarin
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Senyukov
authors.forename: Irina P
authors.initials: IP
authors.lastname: Ivanova
authors.forename: Zoja A
authors.initials: ZA
authors.lastname: Akimenko
authors.forename: Irina G
authors.initials: IG
authors.lastname: Tsyrlova
authors.forename: Steve S
authors.initials: SS
authors.lastname: Wolpe
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Kozlov
mesh_terms: D000485:Allergens / Q000276:immunology / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001854:Bone Marrow Cells / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D018920:Coculture Techniques; D017077:Culture Media, Conditioned / Q000494:pharmacology; D003602:Cytotoxicity, Immunologic / Q000187:drug effects / Q000276:immunology; D004900:Erythroblasts / Q000276:immunology / Q000378:metabolism; D041905:Erythroid Cells / Q000276:immunology* / Q000378:metabolism; D004921:Erythropoietin / Q000494:pharmacology; D006801:Humans; D007108:Immune Tolerance / Q000276:immunology* / Q000502:physiology; D007166:Immunosuppressive Agents / Q000276:immunology* / Q000378:metabolism / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000276:immunology; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D009439:Neuraminidase / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D010659:Phenylhydrazines / Q000494:pharmacology; D010740:Phospholipases / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000187:drug effects / Q000276:immunology
chemical_list: D000485:Allergens; D017077:Culture Media, Conditioned; D007166:Immunosuppressive Agents; D008070:Lipopolysaccharides; D010659:Phenylhydrazines; C482199:lipopolysaccharide, E coli O55-B5; C030299:phenylhydrazine; D004921:Erythropoietin; D010740:Phospholipases; D009439:Neuraminidase; D010447:Peptide Hydrolases