FIG. 6.

Inhibition of hemolysis of RBCs by preattached PR8 virus by antibody. Hemolysis is presented as a percentage. Virus was incubated with cells at 4°C for 30 min, and antibody was added for 1 h at 37°C. Incubation was then continued at pH 5 and 37°C for 45 min to allow hemolysis to occur. (a and b) H36 IgG (a) and Fab (b); (c) H9 Fab. Cells were pelleted, and released hemoglobin was determined spectrophotometrically at 520 nm. Data are the mean of four experiments, and the bars represent the standard error of the mean.