CCL2 and infection: Before infection (Day 0), MCP-1/CCL2, MIP-1α/CCL3, and IP-10/CXCL10 levels were higher in OVA challenged mice (OVA) than those in mice without OVA challenge (PBS) (Fig 3F), whereas the levels of these chemokines in OVA/pH1N1 mice fell by Day 3 post-virus infection and the levels in PBS/pH1N1 were higher than those in OVA/pH1N1 mice (Fig 3F).