Identification of Strains of Streptococcus pyogenes of Types 5, 11, 12, 27 and 44 by the Precipitin Test for the T Antigen

Abstract

Strains of Streptococcus pyogenes belonging to types 5, 11, 12, 27 and 44 share a minor T antigen. In addition there are 3 major T antigens in this set of types, one in type 11, one in type 12 and the 3rd common to types 5, 27, and 44. T antigen, prepared by Pakula''s method, is a satisfactory fraction for absorbing the antibodies from serum, the advantage being that very little serum is lost. The Pakula method of extraction of the T antigen can also be satisfactorily used in routine typing. Type 11 strains can be definitely identified by the T precipitin test, and this test can also be used for identifying Type 12 strains that give no reaction with Type 12 anti-M sera. There are some strains which have agglutination patterns of the series 5, 11, 12, and 44 but which give no precipitation with the T antisera. It may be that in these the major T antigen has not been recognized.