Figure 4.
Infectious focus size varies greatly from passage to passage. Infectious foci of selected passages at limiting dilution were examined and the number of infected cells per focus were enumerated. (Median: horizontal line towards middle of box; 5th and 95th percentile values: lower and upper error bars, respectively; 25th and 75th percentile values: bottom and top of the box, respectively; outlier values: filled diamond; nd: not done). A minimum of 20 foci were examined for each passage. See Table 1 for pairwise statistical comparisons and numbers of foci analyzed. Data obtained for each passage were pooled from two to four independent experiments. Note that virus yield, degree of sensitivity of HA and infection to IgY, and focus size varied dramatically over the course of the study. Yield, antibody sensitivity, and focus size correlated poorly for individual passages.