Figure 1.
Purification of CPE agent (s). The supernatant of the infected PLC/PRF/5 cells was concentrated by ultracentrifugation, and further purified by CsCl gradient centrifugation. Aliquots from each fraction were analyzed by 5%–20% SDS-PAGE. Proteins were visualized by Coomassie blue staining (A) and western blotting with SSV-positive serum from Monkey C13 (B). The density of each fraction is shown (C). Virus particles in fraction 6 (D) and 13 (E) were observed by EM. Bar, 200 nm.