title: Role of macrophage-dependent determinant selection in induction phase of streptococcal carditis.
abstract: A genetically controlled antigen-presentation function in macrophages is proposed to explain the induction phase of streptococcal carditis. Antigenic determinants in strains of beta-haemolytic streptococci causing rheumatic fever are selected by macrophages, through the operation of immune response (Ir) genes, to be presented to T lymphocytes. Cross-reactivity between the selected determinants and heart tissue components generates clones of autoreactive T cells. Autoimmunity will develop if, coincidental with the presentation of the relevant antigenic determinant, regulation of T-cell production is disturbed. This hypothesis explains the capacity of different strains of streptococcus to produce rheumatic fever and also the variability in host susceptibility to the disease.
mesh_terms: D000818:Animals; D001327:Autoimmune Diseases / Q000276:immunology; D003429:Cross Reactions; D000939:Epitopes; D005802:Genes, MHC Class II; D006168:Guinea Pigs; D006680:HLA Antigens / Q000235:genetics; D006801:Humans; D007111:Immunity, Cellular; D008264:Macrophages / Q000276:immunology*; D051379:Mice; D008954:Models, Biological; D012213:Rheumatic Fever / Q000276:immunology*; D012214:Rheumatic Heart Disease / Q000209:etiology* / Q000276:immunology; D013290:Streptococcal Infections / Q000276:immunology*; D013297:Streptococcus pyogenes / Q000235:genetics*; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D000939:Epitopes; D006680:HLA Antigens