However, in the absence of sialic acids the expression of DC-SIGN supported the infection of MDCK cells and Vero cells by a number of influenza A viruses including two H1N1 viruses, A/USSR/90/77 and A/Netherlands/364/06, and four H3N2 viruses, A/swine/Oedenrode/7C/96, A/Netherlands/35/93, A/Netherlands/312/03 and A/Netherlands/348/07. The gene discussed is CD209; the disease is infection.