Scientists for the first time have found a way to grow T cells in the laboratory, which will greatly help researchers working on HIV medication and vaccine studies as well as those focusing on other immune system disorders, Nature Immunology reports. The scientists, based in Toronto, made the T cells from mouse embryonic cells. Previous research on mouse and human embryonic stem cells resulted in the production of blood and muscle cells but never immune system cells. Lead researcher Juan Carlos Zuniga-Pflucker and his team were able to produce the T cells by identifying a molecule, called DL1, that is essential in T-cell production. They engineered cells to produce DL1 then grew the embryonic stem cells on top of the molecule, which stimulated the stem cells to produce immune system cells. Zuniga-Pflucker says he hopes one day to grow human T cells to be injected into HIV and cancer patients who have depleted their own stores of the immune cells. Human T cells grown in the lab also could be engineered to better fight HIV in the body, he added.