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Updated: May 8, 2026

Measuring the 50% Haemolytic Complement (CH50) Activity of Serum
Published on: March 29, 2010
Destabilization of CH2 domains in intact IgG2 is accompanied by reduced ability to inhibit complement system factor
1Institute of Theoretical and Experimental Biophysics, Russian Academy of Sciences, 143390 Pushchino, Moscow Region, Russia.
Abstract:
Fc fragments (hFc) of human myeloma IgG2 proteins LOM and SIN having core hinge (Cys-Cys-Val-Glu-Cys-Pro-Pro-Cys) were first obtained by a modified proteolytic procedure. The thermostability of CH2 domains inside of standard Fc, hFc fragments, and intact IgG2 LOM and SIN was studied by fluorescence spectroscopy. It was found that CH2 domains of intact IgG2 are destabilized. The destabilization is accompanied by reduced ability of IgG2 to inhibit the activation of complement system by classical pathway. This could be due to the decrease in the affinity of CH2 domains to factor C1q.
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