Dnmt3a-mediated methylation balances memory Th1 and Tfh cell plasticity and functionality.

Following acute viral infection, naïve CD4+ T cells differentiate into T follicular helper (Tfh) and T helper 1 (Th1) cells that generate long-lived memory cells. However, it is unclear how memory Tfh and Th1 cells maintain their lineage commitment. Here we demonstrate that Tfh and Th1 lineages acquire distinct DNA methylation programs that are preserved into memory.

Interconnected lineage trajectories link conventional and natural killer (NK)-like exhausted CD8 T cells beneficial in type 1 diabetes.

Distinct Natural Killer (NK)-like CD57 and PD-1 CD8 exhausted-like T cell populations (Tex) have both been linked to beneficial immunotherapy response in autoimmune type 1 diabetes (T1D) patients. The origins and relationships between these cell types are poorly understood. Here we show that while PD-1 and CD57 Tex populations are epigenetically similar, CD57 Tex cells display unique increased chromatin accessibility of inhibitory Killer Cell Immunoglobulin-like Receptor (iKIR) and other NK cell genes.

Abatacept increases T cell exhaustion in early RA individuals who carry HLA risk alleles.

Exhausted CD8 T cells (T) are associated with worse outcome in cancer yet better outcome in autoimmunity. Building on our past findings of increased TIGITKLRG1 T with teplizumab therapy in type 1 diabetes (T1D), in the absence of treatment we found that the frequency of TIGITKLRG1 T is stable within an individual but differs across individuals in both T1D and healthy control (HC) cohorts. This TIGITKLRG1 CD8 T population shares an exhaustion-associated EOMES gene signature in HC, T1D, rheumatoid arthritis (RA), and cancer subjects, expresses multiple inhibitory receptors, and is hyporesponsive , together suggesting co-expression of TIGIT and KLRG1 may broadly define human peripheral exhausted cells.

Tet2 deletion in CD4+ T cells disrupts Th1 lineage commitment in memory cells and enhances T follicular helper cell recall responses to viral rechallenge.

Following viral clearance, antigen-specific CD4+ T cells contract and form a pool of distinct Th1 and Tfh memory cells that possess unique epigenetic programs, allowing them to rapidly recall their specific effector functions upon rechallenge. DNA methylation programing mediated by the methylcytosine dioxygenase Tet2 contributes to balancing Th1 and Tfh cell differentiation during acute viral infection; however, the role of Tet2 in CD4+ T cell memory formation and recall is unclear. Using adoptive transfer models of antigen-specific wild type and knockout CD4+ T cells, we find that Tet2 is required for full commitment of CD4+ T cells to the Th1 lineage and that in the absence of Tet2, memory cells preferentially recall a Tfh like phenotype with enhanced expansion upon secondary challenge.