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An M-associated protein antigen (MAP) of group A streptococci

J P Widdowson, W R Maxted, A M Pinney

    The Journal of Hygiene
    |December 1, 1971
    PubMed

    Insights

    Researchers identified a M-associated protein (MAP) in group A streptococci using complement-fixation tests. Antibody to MAP was found in patients with streptococcal infections, particularly those with rheumatic fever.

    Area of Science:

    • Microbiology
    • Immunology
    • Rheumatology

    Background:

    • Group A streptococci possess M-antigen, crucial for virulence.
    • M-antigen is type-specific and a target for protective immunity.
    • Non-type-specific antigens associated with M-antigen warrant investigation.

    Purpose of the Study:

    • To detect and characterize a M-associated protein (MAP) in group A streptococci.
    • To investigate the presence of antibodies against MAP in human sera.
    • To correlate MAP antibody levels with streptococcal infections and rheumatic fever.

    Main Methods:

    • Complement-fixation test utilized to detect streptococcal antigen.
    • Acid extraction and purification of M-antigen and associated proteins.
    • Analysis of sera from patients with streptococcal infections and rheumatic fever.

    Main Results:

    • A non-type-specific streptococcal antigen, MAP, was detected in M-positive variants.
    • Purification enhanced the purity of both M-antigen and MAP.
    • Antibodies to MAP were present in patients with streptococcal infections, with highest titers in rheumatic fever patients.

    Conclusions:

    • MAP is a distinct antigen associated with M-antigen in group A streptococci.
    • MAP is immunogenic in humans following streptococcal infection.
    • MAP antibodies may serve as a marker for streptococcal infection and are elevated in rheumatic fever.

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