Antiviral effects of rhIFN-alpha 1 against seven influenza viruses.

Aim: To study the antiviral effects of rhIFN-alpha 1 (Chinese silkworm gene recombinant interferon alpha 1) on 7 influenza viruses in MDCK cells and in mouse pneumonia caused by PR8 virus.

Methods: 100TCID50 virus (H1N1, H2N2, H3N3, type B, type C, clinical A1, and clinical B) were inoculated into MDCK cells, PR8 viruses were dropped nasally in mice, the antiviral effects of rhIFN-alpha 1 were observed.

Results: The minimal effective concentrations 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 therapeutic 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), respectively. The inhibitory indices of rhIFN-alpha 1 to the 7 influenza viruses in MDCK cells were 3.6, 4.7, 3.5, 3.3, 3.9, 4.6, and 3.5, respectively. 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 hyperplasia of interstitial fibers, and decreased the virus titer. The inhibitory rates 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.