UCLA scientists have shown that they can engineer adult blood stem cells so that they lack a molecule necessary for HIV infection. The CCR5 receptor is a protein molecule on the surface of cells that is bound by HIV when the virus infects certain immune cells, acting as a receptor for the virus. The scientists used "short hairpin RNA" to knock down the expression of the CCR5 molecule in the human adult stem cells, effectively preventing the protein from being produced. These cells could reconstitute the immune system in a mouse model, indicating that the function of the immune cells was not inhibited. But the human cells, now without the CCR5 protein receptor, resisted HIV infection. The study, published in the journal Blood, provides a potential method for controlling HIV infection in patients.

The study follows a previous report of successful adult stem cell treatment for leukemia that also appears to have controlled HIV infection in the patient. The doctors specifically used an adult stem cell donor whose cells lacked the CCR5 molecule.