Antigenic properties of hemolytic streptococci L-forms

Summary

The results of studying the antigenic structure of the streptococci L-forms and their revertants indicate that the antigenic component of the C-polysaccharide group (Lancefield) is largely lost during the process of L-transformation, this being due to biosynthesis block in cell walls. The component is restored in L-form reverts. L-form streptococci contain a complex antigen extractable after Grasse. This antigen occurs less frequently in the reverts. The efficacy of the antigen complex extraction after Grasse in the L-forms, less distinctly pronounced in the reverts, is evidently associated with the absence of the cell wall in L-forms and the presence of the indestructable wall in the coccal forms which resist freezing and thawing.

Employment of the fluorescent antibodies method in the direct Coons reaction demonstrated a different localization of the antigens in bacterial L-forms of streptocci. Superficially located antigenic components of the cell wall were detected in the former (L-form, including the L-form strains-reverts); in the latter (coccal form), due to the biosynthesis block of the cellular walls, antigenic components located in the cytoplastic membrane were revealed.

Proceeding from the formerly established fact of increased vulnerability of cell walls in the cultures reverted from L-forms, the cell walls were destructed by means of lysozyme. The use of such “wall-devoid” form for a serological analysis, aimed at establishing a possible antigenic affinity between L-forms and their reverts, has made it possible to ascertain the presence of common antigenic components of cytoplasmic origin.