Investigating the effect of variable interferon signaling on CD4+ T cells 2307707

Introduction Inflammation guides immune responses but must be balanced: too little limits memory formation, while too much causes pathology. IFN-I is induced during infection, yet its role in CD4+ memory differentiation is unclear. Our lab found that CD4+ T cell memory differs after SARS CoV 2 vaccination versus infection, with infection primed cells enriched for IFN I related genes. I hypothesize that stronger IFN-I during priming programs distinct CD4+ memory and alters recall responses. Methods To define how IFN-I signaling shapes CD4+ T cell development and function, we must isolate the effect of IFN-I to just CD4+ T cells. Conventional IFNAR-/- mice cannot tune IFN-I signaling strength to CD4+ T cells, and antibody blockade lacks CD4+ specificity and cannot test strong or sustained IFN-I cues. I will instead use Ifnar1S526A and Ifnar2Y510F mice with gain- and loss-of-function point mutations in IFNAR, respectively, that have been demonstrated in cell lines, enabling more precise tuning of IFNAR signaling and systematic analysis of IFN-I effects on immunity. Results Ifnar1S526A mice retain more Ifnar1 on the cell surface, boosting Ifnar density and signaling duration. These mice have more effector-memory CD4+ T cells through spectral flow cytometry, indicating enhanced IFN-I—driven differentiation. Naive Ifnar1S526A CD4+ T cells show elevated interferon stimulated gene expression by RT-qPCR compared to WT, confirming that the mutation increases baseline IFN-I signaling. We generated Ifnar2Y510F mice that carry a TYK2-disrupting mutation that reduces Ifnar2 signaling and validated by Sanger sequencing as a hypomorphic contrast to hypermorphic Ifnar1S526A mice. Conclusion Together, these gain- and loss-of-function IFNAR mutants provide a tunable system to define how IFN-I intensity programs CD4+ T cell memory. By comparing Ifnar2Y510F and Ifnar1S526A mice, this work reveals how graded IFN-I cues shape CD4+ T cell differentiation.