Phenotypic and genotypic association of induction of IL-6 and CCL5 by clinical isolates of RSV. A549 cells were infected with clinical isolates at a moi of 0.13. Cytokine levels (IL-6 and CCL5) in cell culture supernatants were measured at 16 hours after infection. Groupings of clinical isolates were based on phylogenetic analysis of the RSV G gene as demonstrated by the phylogram beneath the graph. Viruses containing the RSV G gene 60 base duplication are designated with the *.