When bound to surface antigens they induce apoptosis, complement and antibody dependent cytotoxicity of lymphoma cells.
Two types-type I are rituximab like.
Most monoclonal antibodies are type I.
Type I antibodies cause rapid redistribution of CD20 into lipid rafts and are involved in complement activation.
Type II antibodies do not cause redistribution of CD20 but they induce homotypic adhesion resulting in antiproliferative effects, cell signaling and apoptosis (Teeling).