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Interaction of human polymorphonuclear leukocyte (PMN) elastase with human IgM. Production of a factor enhancing PMN

H E Prince, J D Folds, J K Spitznagel

    Immunological Communications
    |January 1, 1980
    PubMed

    Insights

    Human polymorphonuclear leukocyte (PMN) elastase digestion of IgM produces peptides that enhance PMN locomotion. These peptides, derived from the Fc5u region, are heat-stable and aid immune cell migration.

    Area of Science:

    • Immunology
    • Biochemistry

    Background:

    • Human monoclonal immunoglobulin M (IgM) plays a crucial role in the immune system.
    • Polymorphonuclear leukocyte (PMN) elastase is an enzyme involved in inflammatory processes.

    Purpose of the Study:

    • To investigate the in vitro effects of human PMN elastase digestion on human monoclonal IgM.
    • To identify and characterize peptide fragments generated from IgM degradation that influence PMN function.

    Main Methods:

    • In vitro digestion of human monoclonal IgM using purified human PMN elastase.
    • Assessment of PMN locomotion using the migration-under-agarose assay.
    • Characterization of the migration-enhancing factor's stability and molecular weight.

    Main Results:

    • Elastase digestion of IgM yielded both large fragments and smaller peptides.
    • These small peptides, particularly from the Fc5u portion, significantly enhanced PMN migration in vitro.
    • The migration-enhancing factor demonstrated stability at 60°C but was inactivated by boiling, with a molecular weight between 1,000 and 10,000 daltons.

    Conclusions:

    • Human PMN elastase degrades IgM into bioactive peptides.
    • These peptides, derived from the Fc5u region of IgM, act as chemoattractants, enhancing PMN migration.
    • The findings suggest a novel mechanism by which IgM fragments modulate inflammatory responses.

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