366 IMMUNOLOGY 



There is some correlation of type specific substance with viru- 

 lence, but a strain of "A" group may lose its virulence and still 

 retain the Matt type of colony. 



This work has assumed great importance because of the con- 

 sistency with which group ''A" streptococci are associated with 

 human infection. 



Recently another type specific antigen designated as "T" has 

 been found in group A streptococci in both Matt and glossy 

 strains. It has not been defined chemically but it is responsible 

 for type specific agglutination. Anti "T" serum exerts no pro- 

 tective effect in mice. The following antigens have been de- 

 scribed by Lancefield : 



Group specific carbohydrates (C) 



Type specific protein for group ''A" (M) 



Type specific substances (T) 



Type specific carbohydrates for groups (S) 

 other than "A" 



To obtain extracts for use in the precipitin work Lancefield 

 extracts the streptococci with hot (boiling) N/20 IICl to de- 

 stroy a Group factor "P" which overlaps with other organisms 

 like pneumococei. She separates the type specific "M" sub- 

 stance from the Group specific (C) carbohydrate by neutralizing 

 the acid extract and precipitating out the "M" substance with 

 alcohol. The Group specific polysaccharide "C" remains in 

 the supernatant fluid. For detailed description of the technique 

 involved the student is referred to Lancefield 's original paper. 

 They might also be interested in a modification of Lancefield 's 

 method reported by Brown* (1938) and in a new method sug- 

 gested by Fuller (1938). 



Other Bacterial Specific Substances. — The specific substance of 

 meningococcus Type I is reported by Scherp and Rake (1935) 

 as sodium salt of a polysaccharide acid containing firmly bound 

 phosphoric acid. Julianelle and Wieghard (1935) have described 

 two type specific polysaccharides for staphylococci. Sievers and 

 Zetterberg report that spontaneous agglutination interfered with 

 their experimental study of aerobic spore forming bacteria. They 

 obtained results with autolysates which suggests the existence of a 



*Brown. J. H. : J. A. M. A. Ill: 310, 193S. 



