Remarkably, the expression levels of TLR3 and S1PR1 were upregulated in the brain following infection with SW8 and ZH283, yet showed different expression patterns in lymphoid tissues. Similarly, the production of TLR7, IL-1β, IL-6, IL-10, and IFN-γ were upregulated in the lung but downregulated in brain, spleen, and bursa of Fabricius in response to both viruses. Such results suggest that the engagement of the TLRs and cytokines are involved in a tissue-dependent manner. Previous studies have revealed tissue-specific immune responses following infection with H5N1 (Wei et al., 2013), H5N2 (Vanderven et al., 2012), and H7N1 (Cornelissen et al., 2012). The difference of cell types could be associated with immune responses and virus titers in the tissues tested for infection.