XK and infection: The results observed for neutralization at one day post-infection by FFA analysis showed that MDCK cells were similar (<1 log2 lower) or superior (>1 log2 higher) to Caco-2 and Mv1 Lu cells for all seven viruses using specific animal antiserum that block virus attachment (anti-HA antiserum), virus release from infected cells (anti-NA antiserum) or polyvalent antiserum (ferret anti-influenza antiserum).