title: Myosin-reactive autoantibodies in rheumatic carditis and normal fetus.
abstract: EBV-transformed B cells from a 20-week human fetal spleen and from blood of patients with poststreptococcal rheumatic carditis were studied. Most antibodies from nine fetal and six patient myosin-reactive B cell clones were multireactive (reacting with cardiac myosin, Streptococcus pyogenes, and rat cardiac myocytes) which supports a role for molecular mimicry in stimulation of these autoantibodies. Sequence analysis revealed that fetal and patient anti-myosin repertoires were composed of unrelated clones with diverse V gene usages. Fetal and patient antibodies had reduced VH CDR3 length on average and reduced light chain N region addition with a low rate of somatic mutation in the variable region genes, characteristics generally associated with fetal B cells but also with some adult B cells. Five of six myosin-reactive patient clones used VH3, whereas only two of nine fetal clones used VH3, suggesting skewing from the average 50-60% VH3 gene usage found in randomly selected adult and fetal antibodies.
authors.affiliation: Department of Pathology, University of Texas Houston Health Science Center, Houston 77030, USA.
authors.forename: X
authors.initials: X
authors.lastname: Wu
authors.forename: B
authors.initials: B
authors.lastname: Liu
authors.forename: P L
authors.initials: PL
authors.lastname: Van der Merwe
authors.forename: N N
authors.initials: NN
authors.lastname: Kalis
authors.forename: S M
authors.initials: SM
authors.lastname: Berney
authors.forename: D C
authors.initials: DC
authors.lastname: Young
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology; D001323:Autoantibodies / Q000097:blood / Q000276:immunology*; D001402:B-Lymphocytes / Q000276:immunology; D002478:Cells, Cultured; D003429:Cross Reactions; D005312:Fetal Blood / Q000276:immunology; D005333:Fetus / Q000276:immunology*; D006801:Humans; D009205:Myocarditis / Q000097:blood / Q000276:immunology*; D009218:Myosins / Q000276:immunology*; D051381:Rats; D012214:Rheumatic Heart Disease / Q000097:blood / Q000276:immunology*; D013154:Spleen / Q000166:cytology / Q000276:immunology; D013297:Streptococcus pyogenes / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001323:Autoantibodies; D009218:Myosins