In order to determine if the peptides were exerting their effects on post-entry steps in the virus replication cycle, DENV-2 was allowed to infect LLC-MK2 cells before peptide was added to the cells ( Figure 6 ). No inhibition of viral replication was observed at any concentration of DN57opt ( Figure 6A ) or 1OAN1 in these assays ( Figure 6B) , indicating that the peptides are not acting at a post-infection step.