T-cell, CD4, Influenza, tissue resident memory, STAT1, STAT4, lung


How CD4 T cells protect against influenza A virus is poorly understood. Here, we address two central questions to better understand how CD4 T cells contribute to immunity during primary and secondary infection. First, we investigate the CD4 T cell-intrinsic requirements for three major transcription factors associated with an antiviral T cell phenotype (termed ‘Th1'): STAT1, STAT4, and T-bet, in directing CD4 T cell responses. We show that STAT4-deficiency does not affect the phenotype or function of wildtype or T-bet-/- CD4 T cells while STAT1-/- cells are virtually undetectable in infected host mice. Depleting NK cells rescues the STAT1-/- cells that phenocopy the compromised Th1 identity of T-bet-/- cells. Finally, we show that cytokine-mediated STAT4 activation enhances infection-induced Th1-polarization and that engaging STAT1 and STAT4 during priming dramatically improves CD4 T cell antiviral capacity. These results are relevant to T cell-based vaccine strategies aiming to promote the most efficient anti-viral T cell responses. Second, we asked the extent to which the recall of influenza-specific lung-resident memory CD4 T cells (TRM) impact the generation of new primary anti-viral T cells. TRM rapidly induce local inflammatory responses that control infection before protective T cells activated in secondary lymphoid organs reach sites of infection. Whether antigen-sensing by TRM can impact T cell priming in secondary lymphoid organs is unclear. We show that activation of influenza-primed lung TRM by antigen delivered into the airways enhances the number and activation status of antigen-bearing dendritic cells in draining lymph nodes. This accelerates the priming of naïve T cells and enhances their recruitment to the lung. Importantly, this TRM-dependent circuit enables productive T cell responses even against levels of airways antigen too low to otherwise activate naïve T cells. This adjuvant-like impact of lung TRM highlights a novel integration of local and regional T cell immunity.

Completion Date




Committee Chair

McKinstry, Karl Kai


Doctor of Philosophy (Ph.D.)


College of Medicine


Burnett School of Biomedical Sciences





Release Date

June 2027

Length of Campus-only Access

3 years

Access Status

Doctoral Dissertation (Campus-only Access)

Restricted to the UCF community until June 2027; it will then be open access.