After GZ-R6 infection of HAE, IL-6 and IL-1b significantly increased at both sides during the early infection stage at 2 d.p.i., and then decreased rapidly (Figure 6A); however, IL-8, CD106, IL-2, CD54, IFN-γ, IL-4, CCL5, TNF-α and IL-10 showed significant increases only at the basolateral sides at different infection times, and no differences were observed at the apical side (Figure 6B). Here, TNF is linked to infection.