Comparison of Streptomyces albus muramidase-extracted streptococcal antigen with acid-extracted M antigen and with pepsin-extracted T antigen.

Purified Streptomyces albus lytic enzyme was used in an attempt to extract type-specific antigen from a type 1, group A streptococcus. The presumably type-specific antigen was purified by ammonium sulfate fractionation followed by chromatography on O-(carboxymethyl)-cellulose columns. Comparison of the enzyme-extracted substance with acid-extracted material showed it to be serologically different from M protein. In addition, the extract obtained by enzyme treatment was resistant to trypsin as well as to the lytic enzyme. It was inactivated partially by pepsin and totally by papain. Comparison of the enzyme extract with pepsin-extracted T antigen showed these two preparations to be serologically identical. Subtle differences in their susceptibility to heat and acid treatment were noted. Immunodiffusion analyses of acid-extracted M protein and pepsin-extracted T protein, as well as with the enzyme extract, clearly established that the M-protein preparation contained a component serologically identical with one of the precipitinogens common to the other two extracts.