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Evaluation of the Interplay Between the Complement Protein C1q and Hyaluronic Acid in Promoting Cell Adhesion
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The C1q binding activity of IgG is modified in vitro by reactive oxygen species: implications for rheumatoid

H R Griffiths1, J Lunec

  • 1Division of Chemical Pathology, Hodgkin Building, Leicester, UK.

FEBS Letters
|June 17, 1996
PubMed

IgG can be denatured in vitro by reactive oxygen species (ROS). Native IgG activates the complement cascade through C1q. Using a modified ELISA, C1q binding activity of rheumatoid IgG has been compared to IgG denatured by neutrophil-derived ROS. The C1q binding activity of rheumatoid synovial fluid IgG is greater than the corresponding serum IgG (P < 0.01). Denaturation of IgG by activated polymorphs or the Fenton reaction decreased its C1q binding activity (P < 0.01). In vitro exposure of IgG to OH. and ROO. increased its interaction with C1q (P < 0.01). Hypochlorous acid had no effect. ROS-induced alteration to IgG-C1q binding activity may promote the inflammatory response in rheumatoid arthritis.

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