By David Douglas
NEW YORK (Reuters Health) - Research in monkeys suggests that hematopoietic stem/progenitor Cclls (HSPCs) in concert with chimeric antigen receptor (CAR) T-cells could provide long-lasting protection against HIV.
As senior author Dr. Scott G. Kitchen told Reuters Health by email, "I believe that our study illustrates the potential in a stem cell gene therapy to suppress HIV long term and even possibly eradicate the virus in the body. This lays the foundation for future work developing this approach to direct the immune system to better target HIV."
In a December 28 online article in PLoS Pathogens, Dr. Kitchen of the University of California, Los Angeles (UCLA), and colleagues report that they came to these conclusions after studying pigtail macaques infected with simian human immunodeficiency virus (SHIV).
HSPC-based CAR therapy, the investigators go on to say, "has several benefits over T-cell gene therapy, as it allows for normal T-cell development, selection, and persistence of the engineered cells for the lifetime of the patient."
For the current study, the team used a CAR molecule "that hijacks the essential interaction between the virus and the cell surface molecule CD4 to redirect HSPC-derived T-cells against infected cells."
These CAR-engineered HSPCs were engrafted into the bone marrow of the animals, and the team observed "multilineage engraftment of autologous, gene-modified cells that persisted for almost 2 years." Moreover, they found that CAR-expressing cells expanded in response to SHIV infection in an antigen-driven fashion.
In addition, say the investigators, there was "wide distribution of these cells in lymphoid tissues and gastrointestinal tract, which are major anatomic sites for HIV replication and persistence in suppressed patients." No adverse effects were observed.
The study, they conclude, "demonstrates for the first time the safety and feasibility of HSPC-based CAR therapy in a large animal preclinical model," adding that it "clearly demonstrates the potential of using CAR gene therapy in HSPCs to redirect anti-HIV immunity against HIV-1 infection."
PLoS Pathog 2017.