Characteristics of The Extracellular M Proteins of Group-A Streptococci

Pinney, Alison M.; Widdowson, Jean P.

doi:10.1099/00222615-10-4-415

Cited by 5 publications

(4 citation statements)

References 23 publications

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“…In contrast, acid-extracted type 12 M protein, a type similar to type 6 M protein, consists of small homogeneous subunits of about 32,000 molecular weight (15). Culture supernatants of M types 5, 12, and 30 have been shown to carry M protein molecules with molecular weights that ranged from 5,000 to 150,000 (14), an observation that is apparently true of culture supernatants of S. equi (Table 1). M protein fragments of the latter had higher molecular weights in culture supernatant than in acid extracts (Fig.…”

Section: Resultsmentioning

confidence: 99%

Immunologically reactive proteins of Streptococcus equi

Timoney¹,

Trachman²

1985

Infect Immun

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Immunologically reactive proteins in acid extracts and culture supernatants of Streptococcus equi were recognized through a combination of chromatographic and immunologic procedures. Both highand low-molecular-weight components of each of these protein preparations were protective for mice and were, therefore, presumed to contain a variety of hydrolytic products or fragments of the M protein of S. equi. Convalescent horse sera that exhibited strong bactericidal activity for S. equi always reacted with polypeptides in the molecular weight range of 24,000 to 29,000, whereas preinfection sera did not. Rabbit antisera to affinity-purified S. equi protein also reacted with these polypeptides, as well as with a polypeptide of about 36,000 to 37,000 molecular weight. M protein in acid extract and culture supernatant did not cross-react in immunodiffusion, but rabbit antiserum to affinity-purified M protein from an acid extract of S. equi reacted strongly with culture supernatant proteins of approximate molecular weights of 67,000, 58,000, and 43,000. We suggest, therefore, that the M protein in culture supernatant is masked by other sequences that are removed by hot acid during preparation of acid extracts. Polypeptides common to acid extracts of S. equi and Streptococcus zooepidemicus were also identified. These polypeptides had molecular weights of about 55,000 and 31,000.

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Section: Resultsmentioning

confidence: 99%

Immunologically reactive proteins of Streptococcus equi

Timoney¹,

Trachman²

1985

Infect Immun

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“…It has a close association with M antigen (Widdowson et al, 1970;Widdowson et al, 1971) and may affect the pathogenicity and virulence of strains by virtue of its influence on the antigenicity of other streptococcal products (Gooder, 1961;Top and Wannamaker, 1968;Widdowson et al, 1970;Widdowson et al, 1974;Pinney and Widdowson, 1977). The aim of this study has been to elucidate the physicochemical nature of OF in terms of mol.…”

Section: Discussionmentioning

confidence: 99%

The Opacity Factor of Group-A Streptococci

Hallas

Widdowson

1982

Journal of Medical Microbiology

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“…Culture supernates of OF-positive strains contained easily detectable OF but apparently little M protein (Pinney and Widdowson, 1977).…”

Section: Extraction Of Of and M Proteinmentioning

confidence: 99%

“…In this test the guinea-pig antiserum was used at a dilution of 200 to eliminate any cross-reactions. The presence of type 22 M protein was also monitored by testing fractions for their ability to neutralise type-specific opsonic antibodies in human immune serum in the "direct" bactericidal test (Pinney and Widdowson, 1977).…”

Section: Introductionmentioning

confidence: 99%