title: The use of the serum opacity reaction in the typing of group-A streptococci.
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D001769:Blood; D003429:Cross Reactions; D006736:Horses / Q000276:immunology; D007106:Immune Sera; D012703:Serotyping; D013291:Streptococcus / Q000145:classification* / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001426:Bacterial Proteins; D007106:Immune Sera