TLR9 and bacterial pneumonia: To determine which cells were responsible for reduced IL-17 production in mutant mice during bacterial pneumonia, we performed flow cytometry to quantitated the number and % of CD4+ T cells and γδ T cells expressing intracellular IL-17 in WT, TLR4lps-d, TLR9−/− and TLR4lps-d/TLR9−/− double mutant mice 24 hours post i.t. Klebsiella challenge.