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Predominance of immunoglobulin G sub-class 3 among the complement-fixing antibodies to streptococcal M-associated

G E Mortimer, J P Widdowson

    Clinical and Experimental Immunology
    |August 1, 1979
    PubMed

    Insights

    Group A Streptococcus antibodies to M-associated protein (MAP) were not fully absorbed by Staphylococcus aureus, unlike other antibodies. This suggests a unique IgG subclass distribution, potentially impacting immune response to streptococcal infections.

    Area of Science:

    • Immunology
    • Microbiology
    • Bacteriology

    Background:

    • Protein A from Staphylococcus aureus is used to investigate antibody absorption.
    • Group A Streptococcus (GAS) infections elicit various antibody responses.
    • Understanding antibody-antigen interactions is crucial for diagnostics and therapeutics.

    Purpose of the Study:

    • To investigate the absorption of group-A streptococcal antibodies by protein A-positive Staphylococcus aureus.
    • To characterize the immunoglobulin G (IgG) subclasses involved in the antibody response to M-associated protein (MAP).

    Main Methods:

    • Utilized density gradient centrifugation to determine antibody class.
    • Employed Staphylococcus aureus (protein A-positive strain) for antibody absorption assays.
    • Analyzed differential absorption of various streptococcal antibodies (anti-MAP, anti-streptolysin O, anti-DNAase B, anti-M, anti-OF).

    Main Results:

    • Complement-fixing antibodies to MAP were only partially absorbed, unlike other streptococcal antibodies.
    • Partial absorption suggests antibodies to MAP belong to specific IgG subclasses.
    • A predominance of IgG3, which does not interact with protein A, was hypothesized for anti-MAP antibodies.

    Conclusions:

    • Complement-fixing antibodies to MAP exhibit restricted heterogeneity and an abnormal IgG subclass distribution.
    • The findings suggest a potential genetic influence on IgG subclass proportions and immune response to streptococcal infections.
    • Implications for understanding secondary sequelae of streptococcal infections are discussed.

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