Antibody-dependentcell-mediatedphagocytosis(ADCP)isoneoftheimportantmechanismsofactionforantibodydrugdevelopment.FcγRIIaisthepredominantFcγreceptorinvolvedintheADCPprocess.FcγRIIaisexpressedinmyeloideffectorcells,includingmacrophagesandneutrophils,whereitplaysaroleintheactivationoftheseeffectorcells.SeveralclinicalstudieshavestudiedthecorrelationofaFcγRIIapolymorphism(R131H)andtheresponsetoIgG1subclassmonoclonalantibodies(mAbs)suchasrituximab.Engineeredamino-acidsubstitutionsinFc-mAbshavebeendevelopedtoenhancethemAb-mediatedphagocytosisoftumorcellsbymacrophages.