FIG. 3.

Impaired NK cell activation in TLR4^null mice after RSV infection. BAL samples from TLR4^null and TLR4^wt mice were harvested 7 days post-RSV or -influenza virus (FLU) infection. NK lytic activity against YAC-1 target cells was determined. Results are expressed as the mean of three independent experiments ± the standard error of the mean. Asterisks indicate a significant difference (P < 0.05) between TLR4^null and TLR4^wt mice. E:T Ratio, effector-to-target ratio.