Macrophage depletion ablates mAb and CR2Fc-mediated protection. Survival of macrophage/monocyte-depleted mice challenged with EL4 and treated with 14G2a alone or in combination with CR2Fc. There was no difference in survival between any of the treatment groups in macrophage-depleted mice. Mice not depleted of macrophages (control) had significantly improved long-term survival, consistent with data shown in Figure 2A; n = 6 to 9.