title: A comparison of two different methods for the serum opacity reaction of Streptococci group A. Occurrence of antibodies against opacity factor in human sera.
abstract: For detection of the opacity factor (OF) in streptococcus group A, two different methods, the slide technique and the blood agar technique, have been compared. The results agree closely. The reaction of OF positive strains on the blood agar medium seems, however, to be more difficult to interpret than the clear-cut opalescence in the slide reaction. Antibody to serum opacity factor was demonstrated in human sera using the solid agar method. Such antibodies were demonstrated in 26 out of a total of 46 ASO positive sera examined.
mesh_terms: D000362:Agar; D000907:Antibodies, Bacterial / Q000032:analysis*; D000942:Antigens, Bacterial / Q000032:analysis; D000989:Antistreptolysin / Q000276:immunology*; D001769:Blood; D006461:Hemolysis; D006801:Humans; D007158:Immunologic Techniques; D008074:Lipoproteins / Q000032:analysis; D010447:Peptide Hydrolases / Q000032:analysis*; D013297:Streptococcus pyogenes / Q000276:immunology*
chemical_list: D000907:Antibodies, Bacterial; D000942:Antigens, Bacterial; D008074:Lipoproteins; C021908:opacity factor; D000362:Agar; D000989:Antistreptolysin; D010447:Peptide Hydrolases