Antigenicity of the M Proteins of Group a Hemolytic Streptococci

Abstract

Epidemiological evidence and laboratory experimentation over the past 20 yr supports the conclusion that immunity to group A streptococcal infection is type-specific. Antibodies directed against the M proteins, the antigens responsible for the specificity of the 50 or more serotypes of group A streptococci, are protective by virtue of their opsonic capacity. This subject has been thoroughly reviewed by Lancefield (1). Recent work has demonstrated that several small doses, e. g. 10/~g, of highly purified M proteins induce type-specific bactericidal antibodies in rabbits (2). The success of these latter experiments has been the impetus for this investigation on the development of a streptococcal vaccine for human use. With highly purified M proteins of types 12, 14, and 24, we have examined the degree of cutaneous hypersensitivity and the level of circulating antibodies in adults and infants. These studies have furnished data on the relative tolerance to M proteins and the possible extent of previous exposure to these serotypes. Secondary bactericidal antibody responses have been induced in adults injected with M protein vaccines without provoking untoward local or systemic reactions. I t is the purpose of this report to ex~mlne the feasibility of type-specific immunization of humans against group A streptococcal infections. Materials and MethodsM Protcin.--Hi~hly purified M proteins were prepared from Group A streptococcal cell walls as previously described (3). A slight modification of the chromatographic procedure eliminated traces of nonspecifie antigens. To a column of carboxymethyl cellulose equilibrated with 0.03 u sodium acetate and containing the M protein sample was added 0.1 ~ sodium acetate buffer at pH 5.5. When the efeuent pH reached 5.5, a linear gradient of 0.1 M potassium phosphate buffer of inc~eAslng pH was applied to the column by adding equal volumes of buffers at pH 6.0, 6.5, and 7.0 to a Technicon "Autograd" mixing chamber for the final elution. Minor fractions of nonspedfic protein emerged prior and subsequent to the elution of the main peak of M protein near pH 6.

Prospects for a vaccine against group A streptococci: The problem of the immunology of M proteins

“…Fox and his associates have been evaluating the response of babies, who tolerate purified M protein relatively well, to alum precipitates of very small doses of highly purified M fractions. 25 It is difficult to be sure that the hemagglutinating antibodies they have stimulated are identical to protective TSA in all cases, but at least in some individuals antibodies have been stimulated which produce positive bactericidal tests. Previous experience convinces us that secondary "booster" responses to M protein vaccines are relatively easy to elicit from patients previously naturally infected with the homologous type.11*35*36 Although the regular induction of ,primary responses require the administration of a great deal more M protein than can usually be tolerated by children or adults, babies may be more promising subjects.…”

Protective Study with a Group A Streptococcal M Protein Vaccine. INFECTIVITY CHALLENGE OF HUMAN VOLUNTEERS

“…Purified M protein vaccines were shown in experimental animals to be immunogenic in the absence of local or systemic reactions. These experiments led to cautious human clinical experimentation with M protein vaccines (5,6). To date, over 150 adults and 90 infants and children have been immunized with M protein vaccines of the more common sterotypes, 1, 3, 6, and 12.…”

“…One dose of APM-1 consisted of 90 ,ug of purified M protein combined with 2.5 mg of aluminum hydroxide in 0. 5 Antibody assay. Serum from each subject was collected just before the vaccine or placebo inoculations and 30 days after the last dosage.…”

Mediation of Cytotoxic Effects of Streptococcal M Protein by Nontype-Specific Antibody in Human Sera

“…Antibodies induced by such vaccines often can be detected only by highly sensitive, but not completely type-specific, methods such as passive hemagglutination (6,18) or CF (5,19).…”