Human blood stem cells engineered to kill HIV

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Could also be used against a range of chronic viral diseases

A proof-of-principle study has demonstrated that it is possible to engineer human blood stem cells into cells that can target and kill HIV-infected cells. The result is the equivalent of a genetic vaccine which is not only good news in the fight against HIV – the process could also be used against a range of chronic viral diseases.

In the study researchers from the UCLA AIDS Institute and colleagues took the “killer” T cells that help fight infection, known as CD8 cytotoxic T lymphocytes, from an HIV-infected individual. The researchers then identified the molecule known as the T-cell receptor – the molecule that guides the T cell in recognizing and killing HIV-infected cells. Although these cells are able to destroy HIV-infected cells, they do not exist in enough quantities to clear the virus from the body. So the researchers cloned the receptor and genetically engineered human blood stem cells, then placed the stem cells into human thymus tissue that had been implanted in mice, allowing them to study the reaction in a living organism.

The engineered stem cells developed into a large population of mature, multifunctional HIV-specific CD8 cells that could specifically target cells containing HIV proteins. The researchers also found that HIV-specific T-cell receptors have to be matched to an individual in much the same way that an organ is matched to a transplant patient.