Splenocytes and cardiocytes were isolated from wild-type and Ro60-knockout C57BL/6 mice, as described in Methods. Splenocytes and cardiocytes were rendered apoptotic by plating on pHEMA plus TNF-α (10 ng/ml, 18 hours, 37°C). FACS analyses of digitonin-permeabilized nonapoptotic splenocytes, after incubation with affinity-purified anti-Ro60 antibodies, are shown in A (upper left: wild-type; lower left: Ro60-knockout). Results of FACS analyses of similarly incubated apoptotic cells are also shown (upper right: wild-type; lower right: Ro60-knockout). (B) Uptake of apopotic Ro60-knockout cardiocytes by neighboring healthy wild-type cardiocytes in the absence (N/A) and presence of: IgG from healthy human donor; affinity-purified anti-La48 (AP48); affinity-purified anti-Ro52; and affinity-purified anti-Ro60.