IL-27 signalling increases lung injury in murine beta-coronavirus and Influenza infection

Abstract

Abstract Introduction: IL-27 is elevated during COPD, ARDS and high levels are predictive of severe SARS-CoV-2 infection. Despite the association with severe pulmonary outcomes, little is understood on how it affects lung injury or cellular recruitment early in viral pulmonary infection. Methods: C57BL/6 (WT) and IL-27ra-/- mice were infected with 500,000PFU of murine beta-coronavirus (MHV-1) or 500PFU of Influenza (H1N1) and evaluated for survival. At days 3 and 5 post infection kinetics of cellular recruitment, viral load and markers of lung injury were evaluated. Results: IL-27ra-/- mice have increased survival compared to the WT mice when infected with MHV-1 (p= 0.0184) and H1N1 (p=0.0305). Despite no differences in viral load, the IL-27ra-/- had decreased lung injury at days 3 and 5 post infection (p<0.05) for both MHV-1 and H1N1. IL-27ra-/- mice had significant neutrophilia during infection at day 3 and 5 (p<0.05) but with altered neutrophil phenotypes (adhesion, activation and maturation markers) including decreased expression of TLR3, TLR4 and CD49d (p<0.05 for all). Conclusion: The IL-27ra-/- mice are resistant to pulmonary infection with MHV-1 and H1N1 with increased survival but no differences in viral load. Despite high pulmonary neutrophilia in both infections, the IL-27ra-/- mice paradoxically have decreased lung injury. This study highlights IL-27 as a potential early target for altering neutrophil phenotypes to limit lung injury during respiratory viral infections.