Fig. 6.
Quantitative detection of C3 in patient serum samples. (A) A linear correlation verified between C3 concentration and detected gel band intensity after SA pull-down assay and SDS-PAGE. Varying concentrations (2× dilution series) of purified C3(bio) were subjected to the SA-pull-down assay and the captured protein analysed by SDS-PAGE and Lumetein staining. Quantified gel band intensities plotted against C3 concentration and the linear trend line displayed. (B) Plasma samples from four surgical patients (1–4) undergoing elective joint replacement were tested for C3 levels before operation (POD0, unfilled bar) and 48–60 h after operation (POD3, filled bar). Four paired patient plasma samples (POD0 and POD3) were incubated with biotin–PEG4–hydrazide and labelled proteins were pulled-down and detected as in A. The quantified C3 gel band intensities (estimated C3 concentrations) were plotted against patient and condition (left panel). The difference seen between POD0 and POD3 was statistically verified in a paired sample t-test to p = 0.09. The average change shown as normalised values of the mean POD0 and POD3 (right panel).