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.
- reactive oxygen species
- C1q binding activity
- rheumatoid arthritis
Griffiths, H. R., & Lunec, J. (1996). The C1q binding activity of IgG is modified in vitro by reactive oxygen species: implications for rheumatoid arthritis. FEBS Letters, 388(2-3), 161-164. https://doi.org/10.1016/0014-5793(96)00542-X