This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Beachey, E. H. Articles by Ofek, I. Search for Related Content PubMed PubMed Citation Articles by Beachey, E. H. Articles by Ofek, I.

 Previous Article  |  Next Article 

Infect Immun. 1974 May; 9(5): 891-896
Copyright © 1974 American Society for Microbiology. All Rights Reserved.

Peptic Digestion of Streptococcal M Protein II. Extraction of M Antigen from Group A Streptococci With Pepsin

¹ Veterans Administration Hospital and the Departments of Medicine and Microbiology, University of Tennessee, Memphis, Tennessee 38104

ABSTRACT

M protein of group A streptococci was extracted by mild peptic digestion. Optimal amounts of type-specific M protein were released after 20 min of digestion with 0.02 mg of pepsin per ml at pH 5.8. Immunological analysis revealed that, unlike conventional HCl extracts, pepsin extracts lacked the surface C carbohydrate antigen and contained less non-type-specific, heat-stable cellular antigens; they also lacked detectable heat-labile T protein. Similar to HCl extracts, however, the pepsin-extracted M protein precipitated homologous-type M antisera and inhibited type-specific opsonization of homologous group A streptococci. Furthermore, the pepsin extract was capable of inducing type-specific opsonic M antibody in rabbits. This method may provide a useful initial step in the purification of M protein by reducing contaminating antigens.

This article has been cited by other articles:

• Kansal, R. G., McGeer, A., Low, D. E., Norrby-Teglund, A., Kotb, M. (2000). Inverse Relation between Disease Severity and Expression of the Streptococcal Cysteine Protease, SpeB, among Clonal M1T1 Isolates Recovered from Invasive Group A Streptococcal Infection Cases. Infect. Immun. 68: 6362-6369 [Abstract] [Full Text]  
• Cunningham, M. W. (2000). Pathogenesis of Group A Streptococcal Infections. Clin. Microbiol. Rev. 13: 470-511 [Abstract] [Full Text]  
• Nishikawa, Y., Shibata, R., Ozono, Y., Ichinose, H., Miyazaki, M., Harada, T., Kohno, S. (2000). Streptococcal M protein enhances TGF-{beta} production and increases surface IgA-positive B cells in vitro in IgA nephropathy. Nephrol Dial Transplant 15: 772-777 [Abstract] [Full Text]