Profiles of released cytokines and chemokines from HEp-2 and A549 cells. Cells were infected with RSV/A/Tracy (GA1), RSV/B/18537 (GB1), RSV/A/Ontario (ON), or RSV/B/Buenos Aires (BA) at a multiplicity of infection (MOI) of 0.01. The cultured supernatants were harvested from mock-infected and RSV-infected cells at 24, 48, 72, or 96 h postinoculation (hpi). Profiles of cytokines and chemokines released into the supernatant were determined by a multiplex Luminex cytokine assay. The fold change of each cytokine or chemokine between virus- and mock-infected cells are shown. Fold changes of cytokines and chemokines released from HEp-2 cells infected with (A) historic RSV strains (RSV/A/Tracy (GA1) and RSV/B/18537 (GB1)) and (B) contemporary RSV strains (RSV/A/Ontario [ON] and RSV/B/Buenos Aires). Fold changes of cytokines and chemokines released from A549 cells infected with historic RSV strains (C) and contemporary RSV (D) strains. At least two independent experiments were performed, and ratios are presented as mean ± SD.