DCX and infection: A/H1N1 viruses A/swine/Iowa/15/30, A/mallard/Netherlands/15/05 and A/PuertoRico/8/34 displayed low infection percentages in MDCK-DC-SIGN cells devoid of sialic acids (0%, 1.9% and 2.6% respectively) and in Vero DC-SIGN cells (3.6%, 10.9% and 3.1% respectively) (figure 5 A and B).