Polarized innate immune response in CHIKV-infected RAW264.7. (A) During the time course of infection, RAW264.7 shows no significant change in IFNα4 mRNA expression by RT-qPCR compared to CLTT. However, a significant increase of ISG-56 at 24 hrs PI was measured for CLTT (fold increase = 121.5 ± 11.5) compare to RAW264.7 (0.7 ± 0.1). (B) A significant increase of TNFα for RAW264.7 at 24 hr PI (fold change = 17.9 ± 3.2) was observed by RT-qPCR and validated by ELISA (fold change = 3.3 ± 0.3). Fold change over non-infected control is expressed as mean ± SEM of three independent experiments.