Effects of autophagy on viral replication and typeI interferon expression in A549 cells during influenza A virus (H1N1) infection
Objective 
To investigate the effects of autophagy on viral replication and type Ⅰ interferon (IFN-Ⅰ) expression in A549 cells during influenza A virus (H1N1) infection for providing references for further elucidation of the mechanisms of influenza virus infection. 
 
 
Methods 
The autophagy inhibitor 3-methyladenine (3-MA) was used to inhibit autophagy. Flow cytometry was used to detect the effects of 3-MA on cell apoptosis. Status of autophagy after infecting A549 cells with H1N1 virus was observed under laser confocal microscopy. Real-time PCR was used to detect the changes in viral copy number and in the mRNA levels of various genes related to the IFN-Ⅰ signaling pathway before and after inhibition of autophagy. 
 
 
Results 
Infecting A549 cells with H1N1 virus induced incomplete autophagy and resulted in autophagosome accumulation. Inhibiting the autophagy of A549 cells with 3-MA up-regulated the expression of various genes in TLR3-TLR7-MyD88-IRF7-IFN-α/β signaling pathway at mRNA level, but down-regulated the viral copy number and hemagglutinin (HA) titer. 
 
 
Conclusion 
Influenza A virus (H1N1) might be able to facilitate its replication and survival by inducing incomplete autophagy to escape from the innate immune responses. 
 
 
Key words: 
Autophagy; Influenza A virus; A549 cell; TypeⅠ interferon