INFLUENCE OF Breg AND IL-10 UPON HUMORAL IMMUNE RESPONSE

• Published in: Medit͡s︡inskai͡a︡ immunologii͡a Vol. 18; no. 4; p. 331
• Main Authors: Gavrilova, M V, Snegireva, N A, Sidorova, E V
• Format: Journal Article
• Language: Russian
• Published: Saint Petersburg Russian Association of Allerologists and Clinical Immuniologists, St. Petersburg Branch 01-01-2016
• Subjects: Antigens; Cell activation; Cell culture; Dextran; Enzyme-linked immunosorbent assay; Immune response (humoral); Immunoglobulin M; Immunoglobulins; Immunoregulation; Interleukin 10; Ionomycin; Lipopolysaccharides; Lymphocytes B; Lymphocytes T; Peritoneum; Rodents; Spleen; Splenocytes
• ISSN: 1563-0625; 2313-741X
• DOI: 10.15789/1563-0625-2016-4-331-338

B regulatory cells (Bregs) are shown to downregulate autoimmune and inflammation processes. Their modifying effects depend on IL-10 secretion. A role of Bregs in development of humoral immune response was not investigated. Influence of Bregs and IL-10 upon in vitro response of murine B1 and B2 cells to T-dependent and T-independent antigens was studied in a model system. A water-soluble sheep erythrocyte antigen was used as a T-dependent antigen, whereas LPS was applied as a type 1 T-independent antigen, and polyvinylpirrolidone and alpha(1→3)dextran were added as type 2 T-independent antigens. В1and B2 lymphocytes were isolated from, respectively, peritoneal cavity and spleen of CBA mice. The cells were cultured in RPMI1640 medium with 10% of FCS supplemented with appropriate antigens and IL-10. The numbers of antibody- and total Ig-forming cells were determined by ELISPOT method. The erythrocyte antigen induced an increase of antibody- and total Ig-forming cell numbers in cultured B1 and B2 cell populations. IL-10 addition caused reduction of antibody- and total Ig-forming cells by 27%. Similarly, IL-10 caused a drop in antibody- and total Ig-forming cells in LPS-stimulated B2 cell cultures by 75%, as well as 50 per cent decrease in numbers of antibody-forming cells in B-1 cell cultures when induced by the type 2 T-independent antigens. To assess functional activity of Bregs, the cells were isolated from peritoneal cavity and spleen of CBA mice. Total yields of Bregs were 20-fold increased upon activation of B cells with LPS, ionomycin and phorbol ester (from 4% to 96%). IgM was the main immunoglobulin isotype secreted by the Bregs. 96% of activated Bregs produced IL-10. About 12% of the cells were shown to produce immunoglobulins. This finding suggests that some of Bregs synthesize both IL-10 and immunoglobulins. To study distant effect of Bregs upon immune response, the splenocyte culture of xid CBA/N mice were tested in Transwells with enriched Bregs. It was revealed that the Bregs caused inhibition of both specific and polyclonal immune response to the water-soluble sheep erythrocyte antigen. Hence, Bregs are shown to participate in humoral immune response, probably, by suppressing functional activity of splenocytes from CBA/N mice to T-dependent antigen. IL-10 secreted by Bregs may play a sufficient role in these regulatory effects.