T Cell Exhaustion Mechanisms in Chronic Viral Infections

Chronic viral infections impose relentless antigenic stimulation on CD8+ T lymphocytes, driving a progressive state of dysfunction known as T cell exhaustion. Exhausted T cells are characterised by diminished proliferative capacity, reduced cytokine production and high expression of co-inhibitory receptors such as PD-1, Tim-3 and LAG-3. Underpinning this phenotype is a complex transcriptional and epigenetic programme governed by factors including TCF1, TOX, Eomes and BATF. The exhausted compartment is not homogeneous but comprises a self-renewing progenitor subset (often TCF1+ and CD62L+) that sustains long-term antiviral immunity and gives rise to terminally differentiated cells with limited effector function. Metabolic reprogramming—marked by mitochondrial dysfunction and shifts from oxidative phosphorylation to glycolysis—further constrains T cell fitness. These insights have informed therapeutic strategies aimed at reinvigorating antiviral responses through checkpoint blockade, metabolic modulation and epigenetic reconditioning. Understanding the balance between progenitor and terminal exhaustion has become central to the design of vaccines and immunotherapies against persistent viruses such as HIV, HBV and HCV, with global implications for disease control.

Research from Nature Portfolio

Recent studies have identified a small population of CD62L+ progenitor exhausted (TPEX) cells that combine self-renewal with multilineage potential, driven by the transcription factor MYB. This stem-like subset preserves long-term antiviral responses and is the exclusive source of proliferative bursts following PD-1 checkpoint inhibition, revealing a dual role for MYB in maintaining exhaustion and preventing immunopathology. In parallel, work on hepatitis C virus has demonstrated that a TCF1+CD127+PD-1+ memory-like CD8+ T cell subset endures long after antigen clearance, surviving direct-acting antiviral therapy and mounting robust recall responses upon re-exposure. These findings underscore the existence of durable, exhaustion-associated memory compartments amenable to therapeutic targeting.

T Cell Exhaustion Mechanisms in Chronic Viral Infections publication trend

The graph below shows the total number of articles in t cell exhaustion mechanisms in chronic viral infections across all publications each year (not limited to Nature Index journals).

Technical terms

T cell exhaustion: A state of T cell dysfunction characterised by reduced effector activity and sustained inhibitory receptor expression following chronic antigen exposure.

Inhibitory receptors: Surface molecules such as PD-1, Tim-3 and LAG-3 that attenuate T cell activation and proliferative responses.

Progenitor exhausted T cells: A self-renewing subset of exhausted T cells, often expressing TCF1 and CD62L, that maintains long-term antiviral immunity.

Terminally exhausted T cells: Differentiated exhausted cells with high inhibitory receptor expression, limited proliferative capacity and reduced cytokine production.

Post-translational regulation: Modification of proteins after synthesis, such as ectodomain shedding by metalloproteases, affecting receptor availability and signalling.

References

1. Targeting a disintegrin and metalloprotease (ADAM) 17-CD122 axis enhances CD8+ T cell effector differentiation and anti-tumor immunity. Signal Transduction and Targeted Therapy (2024).
2. CD39 Expression Identifies Terminally Exhausted CD8+ T Cells. PLOS Pathogens (2015).
3. TCF1+ hepatitis C virus-specific CD8+ T cells are maintained after cessation of chronic antigen stimulation. Nature Communications (2017).
4. A Critical Role of IL-21-Induced BATF in Sustaining CD8-T-Cell-Mediated Chronic Viral Control. Cell Reports (2015).
5. MYB orchestrates T cell exhaustion and response to checkpoint inhibition. Nature (2022).