Serology and immunochemistry ofStreptococcus MG andStreptococcus salivarius

Abstract

Precipitation and cross adsorption show thatStreptococcus NCTC 8037/50 contains the group antigen F of Lancefield and the type antigen III of Ottens. Sera prepared against this strain contain either anti-F and anti-III antibodies or anti-III antibodies only.

The qualitative chemical analysis of the formamide extract ofStreptococcus NCTC 8037/50 and the inhibition of its quantitative precipitation reaction with simple sugars are the same as for a formamide extract of an F III strain.

Nineteen strains, classified by Dr. de Moor (Utrecht) or by Dr. Seeleman (Hamburg) asStreptococcus MG, were serologically identical with either F III, L III, or 0 III (meaning zero III) streptococci. Some of these 0 III strains gave slimy colonies on saccharose agar according to Chapman, and on this property could be regarded asStreptococcus salivarius.

About 70% of 42 freshly isolatedStr. salivarius strains were shown to contain type III antigen. With one of the strains without type III antigen (“strain 51”) an antiserum could be prepared which gave precipitation reactions with all non typableStr. salivarius strains and also with some type III positive strains. This was confirmed by cross adsorption tests.

Qualitative chemical analyses of the hydrolysates of formamide extracts of F III and bothStreptococcus salivarius strains were compared with each other.

The inhibition reaction of the quantitative precipitation of formamide extracts of F III,Str. salivarius N.C.T.C. 8606 andStr. salivarius 51 with the homologous and heterologous sera revealed aβ-glucosidic endgroup of the determinant groups of the III-andStr. salivarius 8606-antigen to be present. Slight differences in the inhibition pattern showed that these determinant groups were not identical. The determinant group ofStr. salivarius 51 is quite different; theβ-glucosidic linked sugars gave no inhibition at all. The best inhibitor was in this case rhamnose, although the inhibition was weak.