CD27high/KLRG1low CD8+ T cells that persist throughout MCMV infection are highly expansive and have the ability to reestablish MCMV immunity

Abstract Cytomegalovirus (CMV) is a herpesvirus that establishes life-long latency in 60-80% of Americans. Constant immune surveillance is necessary to prevent viral reactivation from latency and results in the accumulation of functional CMV-specific CD8+ T cells (CD8s) over time, a process termed memory inflation. As such, CMV reactivations remain a clinical concern for immunosuppressed patients and reconstituting CMV immunity is critical for the long-term prevention of CMV disease. Understanding the maintenance of memory inflation may reveal novel approaches to restore CMV immunity. Previous work has shown that the majority of inflationary CD8s express a terminally-differentiated “effector” (TEFF) phenotype, have a short half-life and appear unable to sustain long-term CMV immunity. Interestingly, inflationary populations also include a minor subset of CD8s that express a “memory” phenotype (TM)