Figure 4.

Dose-dependent binding of gC1qR Δmutants to fixed U937 cells. U937 cells were first attached to 96-well microtiter plates using poly-l-Lysine and fixed as described (Kennet, 1984; Ghebrehiwet et al., 1996). The cells were then reacted with biotinylated gC1qR wild type (WT) or gC1qR deletion mutants (Δ) mutants. After incubation, the plate was developed by sequential addition of alkaline phosphatase conjugated streptavidin followed by pNPP. Each data point is a mean of two experiments run in duplicates and compares the binding of WT gC1qR with gC1qRΔ mutants at two concentrations: 1 and 2.5 μg/ml. The figure in the inset is a dose-dependent binding of WT from which the optimal concentration(s) to be used was determined.