IAV effectively cleaves sialylated HSM. Magnetic beads-conjugated to HSM or PSM were incubated with A/PR/8/34(H1N1), A/Aichi/2/68(H3N2), or buffer at room temperature to allow cleavage of sialylated beads. After 1.5 h incubation the Sia content of the beads was analyzed by DMB-HPLC, and is expressed as percent of Sia content in buffer-incubated beads. Solid bars represent Neu5Ac content, and hatched bars represent Neu5Gc content. Both viruses reduce Neu5Ac content of HSM by 40%-60%, in contrast, only mild cleavage of PSM Sias was observed. ***P<0.001, **P<0.012 *P=0.03 values indicate the significance in difference between Sia content in the virus-treated samples and the corresponding buffer control (two-tailed T-Test, n=3).