CHIKV_mos infectivity can be enhanced after replication in mammalian cells.

<p>The viral stocks of CHIKV_vero-NIH3T3 and CHIKV_mos-NIH3T3 were prepared after CHIKV_vero or CHIKV_mos (Ross strain, MOI = 1) replicated in NIH3T3 for 48 h. (A) NIH3T3 and HFF cells (B) were infected with CHIKV_vero, CHIKV_mos, CHIKV_vero-NIH3T3 and CHIKV_mos-NIH3T3 (MOI = 1), and viral RNA copy numbers were measured at 24 h by RT-qPCR. Data represents ratio of copy number of CHIKV <i>E1</i> to <i>β-actin</i>. (C) NIH3T3 cells were infected with CHIKV_vero-L929 and CHIKV_mos-L929 (MOI = 1), and viral RNA copy numbers were measured by RT-qPCR at 24 h. (D) NIH3T3 cells were infected with CHIKV_vero-VERO and CHIKV_mos-VERO (MOI = 1), and viral RNA copy numbers were measured at 24 h by RT-qPCR. (E) Attachment of CHIKV_vero-NIH and CHIKV_mos-NIH (MOI = 1) were performed in NIH3T3 cells at 4°C for 1 h and attached viruses were measured by RT-qPCR. (F) GAGs neutralization of CHIKV_vero-NIH3T3 and CHIKV_mos-NIH3T3 attachment was performed with heparin (1000 U/mL), chondroitin sulfate A (CSA, 1000 μg/mL) and dermatan sulfate (DS, 1000 μg/mL) in NIH3T3 cells, and the attached viruses were quantified by RT-qPCR and normalized to the respective untreated controls. All data sets represent two independent experiments performed in triplicates. GAG-treated samples were compared to the respective controls (without GAGs) and analyzed using a one-way ANOVA (**** denotes <i>p <</i> 0.0001, *** denotes <i>p <</i> 0.0005, ** denotes <i>p <</i> 0.005, and <i>ns</i> denotes <i>p</i> ≥ 0.05).