Cytokine Expression During the Early Response of A549 Cells to Infection with Influenza Virus, Alphacoronavirus and Betacoronavirus

The escalating incidence of coronavirus infections underscores the critical need for a comprehensive understanding of the differential impacts of Human Coronaviruses (HCoVs) belonging to the Alphacoronavirus and Betacoronavirus genera. This study investigated the varying effects of HCoV-229E (Alphacoronavirus), HCoV-OC43 (Betacoronavirus), and influenza A virus subtype H3N2 on A549 cell viability and cytokine expression. Results showed that H3N2 triggered a more potent cytokine response than HCoV-229E and HCoV-OC43, albeit without inducing apoptosis, HCoV-229E elicited a more potent cytokine response than HCoV-OC43, but HCoV-OC43 was more capable of inducing apoptosis. During the initial 24 h of infection, HCoV-229E and HCoV-OC43 led to significantly greater A549 cell viability reduction than H3N2, potentially attributed to their longer incubation periods. Additionally, the coronaviruses demonstrated enhanced infectivity. Meanwhile, H3N2 induced the production of IL-6, IL-8 and tumor necrosis factor-α. These results provide insights into the protracted incubation periods characteristic of coronaviruses and the cytokine storm observed during infection. Thus, emphasis is placed on the degree of the observed inflammatory response and how it might affect the severity of the condition. These findings provide valuable insights that may serve as a reference for future research on respiratory viruses. The observed distinctions in cell viability, cytokine expression, and infectivity demonstrate the nuanced dynamics of different coronaviruses and can inform the design of strategies for better managing and investigating these infections.