IFN-β was only detected (concentration of 48 ρg/ml) in the supernatant of influenza H5N1 virus (483/97) infected BMDMΦ at 24 hours post-infection but we failed to detect any IFN-β secreted from the supernatants of BMDMΦ after other influenza viruses infection at various time post-infection. This evidence concerns the gene IFNB1 and infection.