To determine whether DENV infection could suppress the cytokine induction triggered by TLR signaling, we investigated infection with a murine macrophage cell line J774A.1. Consistent with previous report that J774A.1 is susceptible to DENV infection [27] , DENV-2 infection in J774A.1 was shown by immunofluorescence staining with antibody specific against DENV-2 NS3 (Figure S1A) , and by qPCR with DENV-2 59 UTR primers ( Figure S1B ). J774A.1 cells were mock-infected or infected with DENV-2, then stimulated with LPS or polyI:C. LPS and polyI:C readily promoted the expression of IFN-b (Figure 2A and B; left panels) and IL-10 ( Figure 2A and B right panels), but with DENV-2, the expression was diminished. Similar results were noticed in DENV-2-infected BMDCs that polyI:C-activated IFN-b and IL-10 were reduced with DENV-2 infection ( Figure 2C ). Thus, DENV-2 appears to interfere with IFN-b and cytokine production triggered by TLRs signaling cascade.