CR2Fc enhances the therapeutic outcome of mAb immunotherapy. Survival (A) and number of liver micrometastases at day 19 (B) of mice challenged with EL4 cells and treated with 14G2a mAb alone or in combination with CR2Fc. Long-term survival is significantly improved with mAb and CR2Fc treatment over mAb immunotherapy alone. Survival data are combined from 2 independent experiments (n = 14), each of which yielded similar results. (B) Data are mean ± SEM; n = 4 or 5. (C) Survival of mice challenged with B16 cells and treated with TA99 mAb alone or in combination with CR2Fc; n = 5.