Figure 7. 91R mAb promotes in vitro complement-dependent cytotoxicity in human leukemic MOLT-4 cells. MOLT-4 cells were opsonized with 91R or isotype-matched mAb (40 μg/ml, 30 min, 37 °C), washed, and incubated (1 h) with 25% active (37 °C) or inactive (56 °C) baby rabbit complement (BRC); cell viability was evaluated in a flow cytometer by 7-AAD staining. (A) Specific complement lysis in the absence of antibody or with 91R, 112509, or isotype-matched mAb (IgG2a or IgG2b). Each condition was analyzed in triplicate. Data show mean ± SEM for four independent experiments. (B) Dose-response curve for specific complement lysis using 91R and a control IgG2b mAb at indicated concentrations. Data show mean ± SEM for one representative experiment of four. (C) Effect of time exposure to BRC. Data show mean ± SEM for triplicates from one representative experiment of two. (D) Specific complement lysis in a dose response curve for BRC. Data show percent mean ± SEM for triplicates from one representative experiment of two. *** P < 0.001, ** P < 0.01, * P < 0.05.