Enterovirus D68 protease 2A affects anti-viral interferon type I pathway

Objective To analyze how enterovirus D68 (EV-D68) protease 2A affects the anti-viral interferon type Ⅰ(IFN-Ⅰ) pathway in 293T cells following infection. Methods Western blot was used to detect the expression of recombinant protease 2A, IFN-α and signal transducers and activators of transcription 1 (STAT1) at protein level. Expression of EV-D68 viral protein (VP1) and protease 2A was analyzed by immunofluorescence at different time points. Cytopathic effects were recorded to calculate 50% cell culture infective dose (CCID50). Expression of the genes involved in the anti-viral IFN-Ⅰ pathway was measured by real-time PCR (RT-PCR). Results The recombinant plasmid pCLIPf-2A was successfully constructed and the expression of recombinant protease 2A could be detected by Western blot 24 h after transfection. The recombinant protease 2A promoted the proliferation of EV-D68 at the late stage of infection and induced the production of IFN-α. Expression of the genes involved in the anti-viral IFN-Ⅰ pathway at mRNA level was up- or down-regulated to different degrees with various trends in different groups following infection. Expression of STAT1 was enhanced in all groups. Conclusions EV-D68 protease 2A promoted the activation of anti-viral IFN-Ⅰpathway in response to viral infection and enhanced the proliferation of virus at the late stage of infection. Key words: EV-D68 infection; Protease 2A; Anti-viral IFN-Ⅰ pathway