Since recent influenza studies have implicated certain cytokines such as CD4 T-cell-derived IFN-γ and TNF-α in lung CD8 TRM cell responses (33), we first examined whether IFN-γ and TNF-α were differentially produced in the lung of CD4 T-cell-competent and -depleted animals following parenteral-primed and RM-pull treatment protocol. Here, CD4 is linked to influenza.