CMV-Specific CD8+ Memory T Cells Re-Emerge After Viral Challenge And Recapitulate CMV Immunity Under Various Adoptive Transfer Conditions

Reconstitution of cytomegalovirus (CMV)-specific immunity following transplant remains a primary clinical objective to prevent CMV disease, and adoptive immunotherapy of CMV-specific T cells can be an effective therapeutic approach. Due to the persistence of CMV, most CMV-specific CD8+ T cells become terminally differentiated effector cells (TEFF). However, a minor subset retains a memory phenotype (TM). Interestingly, recent studies suggest that CMV-specific CD8+ T cells with different phenotypes may have different abilities to reconstitute sustained immunity following transfer. The immunology of human CMV (HCMV) infections is reflected in the mouse model of MCMV infection. We found that HCMV- and MCMV-specific T cells displayed shared genetic programs, validating the MCMV model for studies of CMV-specific T cells in vivo. After transfer, the proliferative capacity of MCMV-specific TM cells was vastly superior to TEFF cells. Strikingly, TM cells expanded and established sustained and diverse T cell populations even after multiple challenges. Although both TEFF and TM cells could protect Rag-/- mice, only TM cells could consistently survive after transfer into immune replete, latently infected recipients and respond if recipient immunity was lost. These data show that CMV-specific TM cells retain memory function during persistent infection and can re-establish CMV immunity when necessary.

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Quinn M, Turula H, Tandon M, Deslouches B, Moghbeli T, Snyder CM