A Johns Hopkins study identifies the enzyme NFS1 as essential for pulling sulfur from cysteine into FeS clusters; when NFS1 is disrupted, T cell proliferation and tumor control suffer, while boosting NFS1 activity enhances proliferation and tumor suppression.

The team shows CD8+ T cells rely on the amino acid cysteine to balance two critical roles: expanding to fight cancer and carrying out cancer-killing activity.

In live melanoma models, NFS1-deficient T cells exhibit weaker tumor control and signs of exhaustion, but activating downstream cysteine metabolism pathways can restore T cell expansion and tumor eradication.

The work, published in Cell and supported by institutions including the Van Andel Institute, CIHR, and the Chan Zuckerberg Initiative, marks a multidisciplinary advance in immune metabolism with translational potential.

Lead author Beth Kelly and the team emphasize that targeting metabolic nodes governing cysteine fate offers a tunable strategy to optimize immune responses against cancer and possibly infectious diseases or autoimmune conditions.

Researchers highlight a previously unrecognized level of metabolic control over immune cell function, suggesting we can fine-tune T-cell responses by directing cysteine toward favorable pathways.

Key contributors include senior author Erika Pearce and first author Beth Kelly, with collaborators such as Minsun Cha and Tatjana Gremelspacher from Johns Hopkins.

The study proposes selectively modulating cysteine use within T cells to boost cancer-fighting responses while preventing T-cell exhaustion.

Limiting cysteine pushes T cells into a hyperactivated state with heightened antitumor signaling but reduced proliferation, illustrating a trade-off between expansion and cytotoxic function.

A dual-pathway model is outlined where targeted cysteine allocation in CD8+ T cells could enhance cancer immunotherapies—like adoptive T cell therapy and checkpoint approaches—while minimizing proliferation loss.

The findings appeared March 31 in Cell and were funded by CIHR, Chan Zuckerberg Initiative, Bloomberg Distinguished Professorship, and others, with Pearce also serving on advisory boards for biotech firms.

Glutathione synthesis acts as a brake on T cell effector functions; inhibiting glutathione after activation can boost antitumor immunity by lifting this antioxidant brake.