Australian scientists have used stem cells to grow an organ in mice critical to the immune system, saying the technique could be used to restore the human immune system in AIDS-HIV and cancer patients.

Gill and fellow researcher Richard Boyd said on Tuesday they had discovered a “small population of cells that can generate a complete and functional thymus.”

The thymus, a small lymphoid organ situated in the neck, is critical in generating cells vital to the immune system, including infection-fighting T-cells.