Amino Acid Cysteine Fuels Cancer-Fighting Power of T Cells

Got story updates? Submit your updates here. ›

A research team from the Johns Hopkins Kimmel Cancer Center, its Bloomberg~Kimmel Institute for Cancer Immunotherapy, and the Johns Hopkins Bloomberg School of Public Health have discovered how the immune system's CD8+ T cells use the nutrient cysteine to control two essential functions that compete for this resource — the immune cell's ability to multiply and its ability to kill cancer cells.

Why it matters

The findings reveal a previously unrecognized level of metabolic control over immune cell function, providing new opportunities to fine-tune T-cell responses in cancer and other diseases by selectively directing how T cells use cysteine to support cancer-fighting immune responses and limit processes that suppress this activity.

The details

The study, published in the journal Cell, shows that cysteine — an amino acid and fundamental building block for life — is required by T cells but is used in different ways. Once inside the cell, cysteine supply is split between two internal pathways that drive distinct T-cell behaviors. One pathway supports cell growth and proliferation, while the other regulates immune activity, including the production of cancer-fighting molecules. The researchers found that limiting cysteine in laboratory models made T cells more active and produced higher levels of immune-signaling molecules that enhanced their cancer-killing function, but they also lost their ability to divide and multiply. Disrupting iron-sulfur cluster formation, which requires cysteine, impaired T-cell expansion and weakened anti-tumor immunity.

• The study was published on March 31, 2026.

What they’re saying

What’s next

The researchers say more research is needed, but the findings point to the potential to selectively direct how T cells use cysteine to support cancer-fighting immune responses and limit processes that suppress this activity.