In this study, we confirmed that influenza virus infection generates lung-resident memory CD4+ and CD8+ T cells which are reported to be crucial for conveying homologous and heterosubtypic immunity that mediate a fast local protection already within 24 hours after homologous infection and by clearing the heterologous virus 36 – 48 hours faster in immune mice than in primary infected mice (18, 47, 48). The gene discussed is CD4; the disease is infection.