Triphasic production of IFNγ by innate and adaptive lymphocytes following influenza A virus infection

Abstract Interferon gamma (IFNγ) is a potent antiviral cytokine that can be produced by many innate and adaptive immune cells during infection. Currently, our understanding of which produce IFNγ where they are located at different stages an infection limited. We have used reporter mice to investigate in vivo expression Ifnγ mRNA the lung secondary lymphoid organs following influenza A virus (IAV) observed triphasic production expression. Unconventional T cells, particularly NK were dominant producers early Ifnγ, while CD4 CD8 main day 10 post-infection. Following viral clearance, some memory continued express lungs draining lymph node. Interestingly, node Natural Killer (NK), NKT type 1 also above naïve levels, suggesting memory-like phenotypes for these cells. Analysis localisation Ifnγ+ demonstrated cytokine+ near airways parenchyma. second IAV challenge, specific rapidly increased their response. Together, data suggest fluctuates based on cellular source location, both could impact subsequent responses.