IL-2 is required for the generation of viral-specific CD4 Th1 tissue-resident memory cells and B cells are essential for maintenance in the lung.

CD4 tissue resident cells are an important first line of defense against viral infections in the lungs and are critical for promoting the localization of lung resident CD8 T cells. However, relatively little is known about the signaling programs required for the development of viral-specific CD4 tissue resident cells in the lungs. Recently, it was shown that signaling through the high affinity IL-2 receptor is required for the differentiation of lung-resident Th2 memory (Trm) cells in a murine model of airway inflammation. We therefore tested if IL-2 signaling is also required for the development of viral antigen-specific CD4 Th1 cells in the lung after i.n. infection with lymphocytic choriomeningitis virus. These studies demonstrate that Th1 CD4 T cells also require IL-2 for lung Trm development. Additionally, they show that B cells potently inhibit early Th1 cell lung residency, but are required for the maintenance of a long-lived population of CD4 Th1 Trm.