The impact of TCR affinity on resident memory T cell formation during influenza virus infection

Resident memory T (TRM) cells in the lung are vital for heterologous protection against influenza A virus (IAV). Environmental factors are necessary to establish lung TRM, however the role of T cell intrinsic factors like T cell receptor (TCR) signal strength have not been elucidated. Here we investigated the impact of TCR signal strength on the generation and maintenance of lung TRM cells after IAV infection. We inserted high and low affinity OT-I epitopes into IAV and infected mice after transfer of OT-I T cells. We uncovered a bias in TRM formation in the lung elicited by lower affinity TCR stimulation. TCR affinity did not impact the overall phenotype or long-term maintenance of lung TRM cells. Overall, these findings demonstrate that TRM formation is negatively correlated with increased TCR signal strength. Lower affinity cells may have an advantage in forming TRM to ensure diversity in the antigen-specific repertoire in tissues. OT-I CD8+ T cells were transferred into mice and animals were challenged with 40 PFU of IAV_N4 or IAV_T4. After 34 days, lungs were harvested after CD8-alpha iv staining, and single cell suspensions were sorted for live CD4-B220-F4/80-CD8+iv-CD45.1+CD45.2-Valpha2+CD44hi cells. Cells were FACS sorted directly into cell cysis buffer for RNA extraction. cDNA libraries were prepared using the SMARTer Universal Low Input RNA Kit (Takara Bio). Samples were then profiled by illumina sequencing