Inhibition of TGF-β1 Signaling Promotes Central Memory T Cell Differentiation

Abstract

This study affirmed that isolated CD8+ T cells express mRNA and produce TGF-β following cognate peptide recognition. Blockage of endogenous TGF-β with either a TGF-β–blocking Ab or a small molecule inhibitor of TGF-βRI enhances the generation of CD62Lhigh/CD44high central memory CD8+ T cells accompanied with a robust recall response. Interestingly, the augmentation within the central memory T cell pool occurs in lieu of cellular proliferation or activation, but with the expected increase in the ratio of the Eomesoderm/T-bet transcriptional factors. Yet, the signal transduction pathway(s) seems to be noncanonical, independent of SMAD or mammalian target of rapamycin signaling. Enhancement of central memory generation by TGF-β blockade is also confirmed in human PBMCs. The findings underscore the role(s) that autocrine TGF-β plays in T cell homeostasis and, in particular, the balance of effector/memory and central/memory T cells. These results may provide a rationale to targeting TGF-β signaling to enhance Ag-specific CD8+ T cell memory against a lethal infection or cancer.