Scientists from the David Geffen School of Medicine at the University of California in America genetically engineered ESCs, a good source of human T-cells for research and therapy, and then pushed them in a three-step process to become T-cells, according to New Scientist magazine. T-cells are crucial to the working of the immune system.

    The three steps are: the cells were first given a gene for a green fluorescent protein using a genetically-engineered virus; next, the cells were grown on mouse bone marrow cells; finally, they were injected into a small piece of human thymus which had been implanted in a mouse with a deficient immune system.

    The bone marrow and thymus are known to provide chemical factors necessary for normal T-cell development. In the end, as many as 24 percent of the T-cells in the implanted thymus were proved to have derived from the green fluorescent ESCs. The remainder were produced by the thymus from progenitor cells supplied by a small piece of human liver that was part of the transplant, the scientists said.

    For genetic diseases like X-SCID, a severe immunodeficiency often fatal in the early years of life, ESCs derived that are from the patient could be given a functional version of the defective T-cell gene. For HIV, ESCs could be engineered to lack CCR5, a surface molecule that the virus needs to successfully attack T-cells, according to the scientists.

    If T-cells are destroyed or absent as occurs in HIV and X-SCID respectively, the body cannot fight off infections. Despite their importance, much about the human T-cell's function is unknown because they are difficult to analyze with standard tools of genetic engineering.

    The report said the scientists were now eager to exploit the new technique to better understand the T-cell. Enditem