The recruitment of innate immune cells into the lungs combined with excessive proinflammatory cytokine and chemokine production are hallmarks of influenza virus infection. Chemokines are involved in the recruitment of circulating leukocytes into the inflamed tissues, engendering the adaptive immune response and contributing to the pathogenesis of a variety of diseases. Under our experimental conditions,we observed high levels of the chemokine gene expression in HUVECs 24 h after inoculation with H9N2 viruses or viral particles,indicating that either H9N2 viral particles alone or viral replication in cells led to the transcriptional expressions of chemokine genes