Quantifying Plasma C3c Complement Binding

We used serial plasma dilutions (10%, 5%, 2.5%, 1.25%, and 0.75% in BBS) and pooled plasma of mice belonging to the same experimental group, incubating the samples for 15 min on mannan- (10 µg/mL) or acBSA-coated (25 µg/mL) plates prepared according to a procedure reported previously.^{18 (link)} Plates were washed and incubated for 1 h 30 min at RT with a polyclonal anti-human-C3c antibody (Dako, A0062) diluted to 2.4 µg/mL in wash buffer. After washing, plates were incubated with an alkaline phosphatase-labeled goat anti-rabbit IgG antibody (Sigma A-3812) diluted to 1 µg/mL in wash buffer for 1 h 30 min at RT. After washing, the assay was developed by adding 100 µL of substrate solution (Sigma Fast p-Nitrophenyl Phosphate Tablets, Sigma). The absorbance at 405 nm was then measured using the Infinite M200 spectrofluorimeter managed by Magellan software (Tecan, CH).