Effects Of Oseltamivir On Influenza A Viral Replications In A549 Cell Line

Influenza A virus is one of major pathogens that are able to cause human respiratory disease. It can be either pandemic or local epidemic, harming human healthy and causing huge economic impact. Currently, vaccine inoculation and medication are the two major ways to prevent and treat the infection by influenza A virus. For those who are not in the cover of inoculation and unprotected by the vaccine, medication treatment is more important. Oseltamivir is one of neuraminidase inhibitors that target at the influenza virus. It is wildly used for the treatment of influenza clinically. However, oseltamivir resistant rate of seasonal H1N1 influenza virus has reached to almost 100% worldwide. Even to the 2009 pandemic H1N1 influenza virus, the resistant rate has already to 2.6%. Therefore, in order to provide the guideline for oseltamivir dosage used in clinic, we compared the effects of the different doses of oseltamivir on the replications of influenza A virus in A549 cells.A549 cells were infected by four different influenza A virus (2009 pandemic H1N1, Seasonal H1N1, H3N2 and H9N2), treated by different tested dosages of oseltamivir at the same time. For the monocycle replication (MOI=0.5), infected cells were harvested for NP protein staining; Infected supernatants were harvested for erythrocyte agglutination test when performed as multicycle replication (MOI=0.01).Results:1. During the monocycle replication, effects of oseltamivir to the drug-resistant virus and drug-sensitive one were totally different. Dosage of oseltamivir had little impact for drug-resistant viral replication. In contrast, with the doseage increases from 0 to 0.025μM, especially at the 0.025μM, oseltamivir could significantly boost the drug-sensitive viral importing and then enhance the viral replications. The result indicated that oseltamivir could not treat either drug-resistant or drug-resistant viruses when viruses were in the monocycle.2. Analysis of multicycles replication showed that oseltamivir dosage (0-25μM) had little effects on viral replications or their release. However, oseltamivir could effectively inhibit the propagation of drug-sensitive virus but not the drug-resistant ones, indicating that oseltamivir could treat drug- sensitive viruses but not the drug-resistant ones during the multicycle replication. Therefore, treatment with oseltamivir should be cautious. Since oseltamivir did little for the treatment of drug-resistant virus, substitutes should be prescribed. On the other hand, oseltamivir could be available for the drug-sensitive viruses when viruses were in the multicycle replication. It is suggested that prescription should take the drug use history and courses of disease as the considerations.