Initiating the Classical Pathway: IgG recruitment, Hexamerization, and C1q binding in Real-Time

Jürgen Strasser, Frank J. Beurskens, Rob N. de Jong, Janine Schuurman, Paul W. H. I. Parren, Peter Hinterdorfer, Johannes Preiner

Research output: Contribution to conferencePaper


Complement activation is triggered by the formation of Immunoglobulin (IgG) hexamers on the surface of pathogens, tumors, or autoantigenic cells (1–3). The molecular pathway of how IgG binding to surface antigens initiates and facilitates hexamerization for subsequent complement activation is poorly understood. Here, we employed high-speed atomic force microscopy (4–7) to directly visualize dynamic IgG binding and hexamer formation on antigenic lipid bilayer membranes and subsequent binding of C1q– the first component of complement- in real-time and under physiological conditions. With single-molecule force spectroscopy and quartz crystal microbalance we further characterized the molecular interactions by determining chemical rate constants and energies. Our data suggest a model in which antigen recognition by IgGs nucleates subsequent oligomerization through IgG recruitment from solution or lateral collisions. This finally leads to stable IgG hexamers competent of tightly binding C1q for further advancing the classical complement pathway.
Original languageEnglish
Publication statusPublished - 2018
EventXX. Annual Linz Winter Workshop 2018 - Linz, Austria, Austria
Duration: 2 Feb 20185 Feb 2018


WorkshopXX. Annual Linz Winter Workshop 2018
CityLinz, Austria


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