Defects in Antiviral T Cell Responses Inflicted by Aging-Associated miR-181a Deficiency

Publication date: 19 November 2019Source: Cell Reports, Volume 29, Issue 8Author(s): Chulwoo Kim, Rohit R. Jadhav, Claire E. Gustafson, Megan J. Smithey, Alec J. Hirsch, Jennifer L. Uhrlaub, William H. Hildebrand, Janko Nikolich-Žugich, Cornelia M. Weyand, Jörg J. GoronzySummaryGeneration of protective immunity to infections and vaccinations declines with age. Studies in healthy individuals have implicated reduced miR-181a expression in T cells as contributing to this defect. To understand the impact of miR-181a expression on antiviral responses, we examined LCMV infection in mice with miR-181ab1-deficient T cells. We found that miR-181a deficiency delays viral clearance, thereby biasing the immune response in favor of CD4 over CD8 T cells. Antigen-specific CD4 T cells in mice with miR-181a-deficient T cells expand more and have a broader TCR repertoire with preferential expansion of high-affinity T cells than in wild-type mice. Importantly, generation of antigen-specific miR-181a-deficient CD8 effector T cells is particularly impaired, resulting in lower frequencies of CD8 T cells in the liver even at time points when the infection has been cleared. Consistent with the mouse model, CD4 memory T cells in individuals infected with West Nile virus at older ages tend to be more frequent and of higher affinity.Graphical Abstract
Source: Cell Reports - Category: Cytology Source Type: research