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The red blood cell as a novel regulator of human B‐cell activation
Author(s) -
Len Charlotte S.,
Cao Huan,
Hall Andrew M.,
Vickers Mark A.,
Barker Robert N.
Publication year - 2021
Publication title -
immunology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.297
H-Index - 133
eISSN - 1365-2567
pISSN - 0019-2805
DOI - 10.1111/imm.13327
Subject(s) - cd22 , cd86 , peripheral blood mononuclear cell , immune system , biology , cd40 , b cell , immunology , cd69 , secretion , receptor , blood cell , cell , microbiology and biotechnology , t cell , antibody , endocrinology , cytotoxic t cell , il 2 receptor , biochemistry , in vitro
Non‐immune cells are increasingly recognized as important in regulating immunity, but the role of red blood cells (RBC) remains relatively unexplored, despite their abundance in the circulation and a cell surface rich in potential ligands. Here, we determine whether RBC influence the activation state of human B cells. Separation of RBC from peripheral blood mononuclear cells increased B‐cell expression of HLA‐DR/DP/DQ, whilst reconstitution reduced the levels of B‐cell activation markers HLA‐DR/DP/DQ, CD86, CD69 and CD40, as well as decreasing proliferative responses and IgM secretion. Inhibition of B cells required contact with RBC and was abrogated by either removal of sialic acids from RBC or blocking the corresponding lectin receptor CD22 on B cells. Chronic lymphocytic leukaemia B cells express low levels of CD22 and were less susceptible to inhibition by RBC, which may contribute to their activated phenotype. Taken together, the results identify a novel mechanism that may suppress inappropriate responsiveness of healthy B cells whilst circulating in the bloodstream.