FIG. 4.

Multiplication of a mixture of F2310 (parent) and F2527 (ΔnudA) in guinea pigs infected by the intratracheal route. The datum points represent mean values of the ratio of F2310 to F2527; error bars represent the standard errors of the mean of three independent experiments (total n = 17 animals). The 2310/2527 ratios at 50 h postinfection for both lung and spleen differ significantly from 1.0 (ratio at time zero) by one-sample t tests (P < 0.0001). Symbols: □, lung; ▵ (dotted line), spleen.