mAb and CR2Fc treatment is not protective in FcγR-deficient mice. Survival of FcγR-deficient mice challenged with EL4 and treated with 14G2a alone or in combination with CR2Fc. In the absence of Fcγ-activating receptors, the protective effect of mAb and CR2Fc treatment is ablated in EL4-challenged mice; n = 7 or 8.