Researchers from have for the first time demonstrated that human blood stem cells can be engineered into cells that can target and kill HIV-infected cells — a process that potentially could be used against a range of chronic viral diseases.
The study, accomplished by UCLA AIDS Institute researchers and colleagues, provides a proof-of-principle that human stem cells can be engineered into the equivalent of a genetic vaccine.
"We've demonstrated in this proof-of-principle study that this type of approach can be used to engineer the human immune system -- particularly the T-cell response -- to specifically target HIV-infected cells," said lead investigator Scott G. Kitchen, assistant professor of medicine in the division of hematology and oncology at the David Geffen School of Medicine at UCLA and a member of the UCLA AIDS Institute. "These studies lay the foundation for further therapeutic development that involves restoring damaged or defective immune responses toward a variety of viruses that cause chronic disease, or even different types of tumors."
Taking CD8 cytotoxic T lymphocytes — the "killer" T cells that help fight infection — from an HIV-infected individual, the researchers identified the molecule known as the T-cell receptor, which guides the T cell in recognizing and killing HIV-infected cells. These cells, while able to destroy HIV-infected cells, 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. Results of this study suggest a strategy that could be an effective weapon in the fight against AIDS and other viral diseases.
Adapted from the UCLA announcement.
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