Antiviral effects of rhIFN-alpha 1 against seven influenza viruses

AIM: To study the antiviral effects of rhIFN-alpha(1) (Chinese silkworm gen e recombinant interferon alpha(1)) on 7 influenza viruses in MDCK cells and in mouse pneumonia caused by PR8 virus. METHODS: 100TCID(50) virus (H1N1, H2N2, H3N3, type B, type C, clinical A(1), and clinical B) were inoculated into MDCK cells, PR8 viruses were dropped nasally in mice, the antiviral ef fects of rhIFN-alpha(1) were observed. RESULTS: The minimal effective conce ntrations of rhIFN-alpha(1) against these 7 influenza viruses were 12.5, 25 , 50, 25, 12.5, 25, and 12.5 kU . L-1, respectively. The infectious therape utic indices of rhIFN-alpha(1), to these viruses in MDCK cells were 8 x 10( 3), 4 x 10(3), 2 x 10(3), 4 x 10(3), 8 x 10(3), 4 x 10(3), and 8 x 10(3), r espectively. The inhibitory indices of rhIFN-alpha(1) to the 7 influenza vi ruses in MDCK cells were 3.6, 4.7, 3.5, 3.3, 3.9, 4.6, and 3.5, respectivel y. The rhIFN-alpha(1) inhibited the intracellular replication of influenza viruses effectively, but did not kill viruses directly. The rhIFN-alpha(1) prolonged the life span of mice infected with pneumonia by influenza virus A strain PR8 to 94.2% - 132.7%. It inhibited the inflammation and hyperplas ia of interstitial fibers, and decreased the virus titer. The inhibitory ra tes of rhIFN-alpha(1) to pulmonary-indice were 14.8 % - 37.4 %. CONCLUSION: rhIFN-alpha(1) inhibited the proliferation of influenza virus and improved the symptom of mouse pneumonia caused by influenza virus.