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Freeze-thaw activation of the complement attack phase: I. Separation of two steps in the formation of the active

A Dessauer, U Rother, K Rother

    Acta Pathologica, Microbiologica, Et Immunologica Scandinavica. Supplement
    |January 1, 1984
    PubMed

    Insights

    Physicochemical methods can activate complement component 5 and 6 (C5+C6) independently of classical pathways. Freezing and thawing generates stable, hemolytic C5-C6 complexes without C5a peptide production.

    Area of Science:

    • Immunology
    • Complement System Biology

    Background:

    • Complement activation, specifically the C5-C9 attack phase, typically relies on enzymatic cleavage of C5 into C5b and C5a.
    • C5b then complexes with C6 and subsequently C7-C9 to induce cell lysis.

    Purpose of the Study:

    • To investigate alternative pathways for activating the C5-C9 complement cascade.
    • To explore physicochemical methods for C5+C6 activation independent of convertases.

    Main Methods:

    • Activation of purified C5+C6 by freezing and thawing.
    • Characterization of the activation process in two steps: intermediate formation and hemolytic activity generation.
    • Anion exchange chromatography for separating components and complexes.

    Main Results:

    • Freezing and thawing of C5+C6 generated hemolytic activity (C--56)f.
    • Activation occurred via a time- and temperature-dependent intermediate formation, followed by hemolytic activity induction through freezing and thawing.
    • The intermediate and activated (C--56)f complex were isolated, with the activated complex demonstrating stability.

    Conclusions:

    • Physicochemical activation of C5+C6 is possible without enzymatic convertases or C5a generation.
    • A stable, hemolytic C5-C6 complex can be generated using freezing and thawing techniques.
    • This finding offers a novel approach to studying complement-mediated cell lysis.

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