Effects of RB6-8C5 treatment on influenza infection of CD8+T cell impaired B6.TAP-/-mice. Groups of 5 B6 or B6.TAP-/- mice were treated with mAb RB6-8C5 (RB6) to deplete neutrophils, or with either rat IgG (IgG) or diluent alone (PBS) 1 day prior to influenza virus infection and every second day thereafter as described in Materials and Methods. (A) Survival data and (B) weight loss following infection with 104 PFU (high dose) or 102 PFU (low dose) of HKx31. Mice were weighed daily and results expressed as the mean percent weight change of each group ± SEM, compared to the weight immediately prior to infection. For survival curves, data has been pooled from 2 independent experiments (n = 10 mice/group) and for weight change data is taken from one of two independent experiments (n = 5 mice/group) (C) Viral growth in the upper and lower respiratory tract 7 days after infection with 102 PFU of HKx31. Viral loads were determined in homogenates prepared from lungs and nasal tissue at day 7 post-infection by plaque assay on MDCK cell monolayers. Data represent the mean ± 1 SD from 4–5 mice and the dotted line represents the detection limit of the plaque assay. ** indicates viral titres of RB6-8C5-treated mice significantly different to those of the relevant IgG-treated controls (p < 0.01, Student's t-test).