FIG 8.

PC liposomes trigger ISVP-to-ISVP* conversion and pore formation more efficiently than PC-sulfatide (7:1) liposomes. T3D ISVPs (2 × 10¹² particles/ml) were incubated in virus storage buffer supplemented with CF-loaded EE or EE without PE liposomes (A), CF-loaded PC or PC-PE (2:1) liposomes (B), or CF-loaded PC or PC-sulfatide (7:1) liposomes (C) for 1 h at the indicated temperatures. After 1 h, the reaction mixtures were diluted 1:50 into virus storage buffer. The samples were equilibrated at room temperature for 15 min prior to measuring fluorescence. Levels of 0 and 100% CF leakage were determined by incubating an equivalent number of CF-loaded liposomes in virus storage buffer or virus storage buffer supplemented with 0.5% Triton X-100, respectively, for 1 h at the indicated temperatures. For each condition, the mean percent CF leakage was determined from at least three independent experiments. The same data are shown in the upper and lower panels of panel C, except the range of percent CF leakage in the lower panel is reduced to highlight the differences between samples. Error bars indicate standard deviations. P values were calculated using Student's t test. *, P ≤ 0.05.