The antibody repertoire of early human B cells. I. High frequency of autoreactivity and polyreactivity.
Cord blood and fetal liver B cells were immortalized using Epstein-Barr virus, and IgM antibodies from the resulting lines and clones were examined for their binding to a variety of auto-antigens and micro-organisms by ELISA and fluorescence assays. Auto-antigens tested included Fc of IgG, ssDNA and dsDNA, cardiolipin, histones 1-4, collagens type I and II, thyroglobulin, cytoskeletal components, and a tissue section screen. Of 71 cell lines tested, all but 19 showed some autoreactivity. All 32 fetal liver lines reacted to some self-antigens. In cord blood clones, 16 out of 26 bound to auto-antigens. Many of the clones reacted with more than one auto-antigen and were 'polyreactive'. Some of the cord blood clones bound to extracts of micro-organisms, showing specificity for both endogenous and exogenous antigens. The high frequency of CD5+ B cells in the cord blood (greater than 50%) and fetal liver (greater than 70%) argues for many of these clones being derived from this subset. Therefore, our data support the concept that many 'early' B cells produce polyreactive IgM which can bind to a variety of different auto-antigens and micro-organisms. These IgM antibodies are similar to those described by others as 'natural antibodies'.
Lydyard
P M
PM
Department of Immunology, University College and Middlesex School of Medicine, London, UK.
Quartey-Papafio
R
R
Bröker
B
B
Mackenzie
L
L
Jouquan
J
J
Blaschek
M A
MA
Steele
J
J
Petrou
M
M
Collins
P
P
Isenberg
D
D
D000918:Antibody Specificity; D001323:Autoantibodies / Q000096:biosynthesis / Q000276:immunology*; D001324:Autoantigens / Q000276:immunology; D001402:B-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D001419:Bacteria / Q000276:immunology; D002176:Candida albicans / Q000276:immunology; D002308:Cardiolipins / Q000276:immunology; D002461:Cell Line, Transformed; D002472:Cell Transformation, Viral; D003094:Collagen / Q000276:immunology; D003599:Cytoskeleton / Q000276:immunology; D004247:DNA / Q000276:immunology; D005312:Fetal Blood / Q000276:immunology*; D005333:Fetus; D004854:Herpesvirus 4, Human; D006657:Histones / Q000276:immunology; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism; D007147:Immunoglobulin Light Chains / Q000276:immunology; D007075:Immunoglobulin M / Q000378:metabolism; D008099:Liver / Q000276:immunology*; D013954:Thyroglobulin / Q000276:immunology
D001323:Autoantibodies; D001324:Autoantigens; D002308:Cardiolipins; D006657:Histones; D007074:Immunoglobulin G; D007147:Immunoglobulin Light Chains; D007075:Immunoglobulin M; D003094:Collagen; D004247:DNA; D013954:Thyroglobulin