In response to WNV infection, the frequency of NK cells expressing the chemokine MIP-1β is significantly increased at 8 hours, CD107a (a marker of degranulation as a surrogate for cytolytic activity) is significantly increased at 24 h and 48 h, and IFN-γ is significantly increased at 48 hours post-infection (Fig 1B–1D). The gene discussed is CCL4; the disease is infection.