Zed SRBCs, only rare unopsonized SRBCs appeared bound to ZK1 cells; most cells did not have any unopsonized SRBCs attached. After binding, these unopsonized SRBCs were easily lysed away (Fig. 5A). Approximately 80 of ZK1 cells were positive for FcR-mediated phagocytosis of opsonized SRBCs (Fig. 5B). Similar results were seen in ZK2 and ZK6 clones (data not shown). Decreased binding and phagocytos