FCGR2A and infection: To test this hypothesis,we carried out phagocytosis experiments essentially as described above,but exposed THP-1 macrophages to a polyclonal FcγR- blockingantibody prior to infection with bacteriaor left macrophages unexposed to FcγR blocker as a control.In the absence of FcγR blocker, Tre-DNP-labeled, anti-DNP-opsonizedMabs, M. avium, and Mtb mc27000 underwent significantly increased phagocytosis by macrophagescompared to nonopsonized conditions (Figure ), consistent with the results shown above(Figure ) (see Figure S5 for representative flow cytometry contourplots and gating strategy).