The synergistic antiproliferation effect of anti-CD20/22 bsAb and α-IgM. The combined antiproliferation effect of hA20IgG-(LL2scFv)2 and SA-AD4 was characterized by deriving CI values from the experimental data, that is, the dose-dependent inhibitory effects of each Ab alone and in combination, as described by Reynold and Maurer.13 (A) The dose-effect plot. Dose-dependent growth inhibition by hA20IgG-(LL2scFv)2 (▴), SA-AD4 (■), or hA20IgG-(LL2scFv)2 plus SA-AD4 with a constant molar ratio of 10:1 (▾) on D1-7 cells was determined similarly as in Figure 2. The error bars represent standard deviations of triplicate tests. The nonlinear fitting curves shown in the chart were generated with the Prism 4 software (GraphPad Software) (B). The plot of log CI values derived from the dose-dependent inhibitory curves versus fraction of inhibited cell population. The plot represents the data from 3 sets of independent experiments (each set was in triplicate), as indicated by distinct symbols (●,▴,▾). The solid curve is the best nonlinear fit of all data points. The dotted curves indicate 95% confidence interval (CI) of the nonlinear fitting. In this method, log(CI) > 0 indicates antagonism, log(CI) = 0 indicates an additive effect, and log(CI) < 0 indicates synergy.
