XK and infection: Likewise, in multiple-cycle growth, the two viruses reached comparable yields 24 hours post-infection, but the resistant virus showed a significant growth delay during the first 12 hours post-infection (P<0.05); this delay was more conspicuous in MDCK-SIAT1 cells than in MDCK cells (Figure 1D), probably because overexpressed α2, 6 receptors on cell surface could better differentiate NA's function in support of viral growth.