In vitro phagocytosis of antibody-coated KEL RBCs is observed in wild-type, FcγR KO, and C3 KO, but not FcγR KO × C3 KO (double-KO), splenocytes. Opsonized murine KEL RBCs were incubated in vitro for 15 minutes with splenocytes from (A) wild-type (C57BL/6) mice, (B) FcγR KO mice, (C) C3 KO mice, or (D) double-KO mice lacking FcγR and C3. Scanning was initially completed at low power, and then 30 high-power fields were evaluated in duplicate wells. The microscope used was an Olympus BX40, with an Olympus PLAN 100× objective and a numerical aperture of 1.25 under oil emersion. Images were captured using a SPOT Insight CCD camera (model 14.2) using SPOT basic software (version 4.7).