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Study Shows Stem Cells are Effective Weapon to Combat Biological Warfare

DURHAM, NC - Researchers for the first time have shown how engineered stem cells can be used to deliver antibodies superior to those currently available for protecting against infectious diseases and biological warfare. The study appears in the August issue of STEM CELLS Translational Medicine.

Vaccines and antivirals exist for many such pathogens, but as the recent Ebola outbreak demonstrated, they have limitations – mainly the time it takes to manufacture a quantity large enough to control an epidemic, plus the window of time they offer protection after being administered. The potential for adverse side effects poses yet another issue.

Many researchers believe that engineered mesenchymal stromal cells (MSCs) are an attractive alternative. The SCTM study's lead authors, Wei-Gang Hu, Ph.D., and Les Nagata, Ph.D., of the Defence Research and Development Canada, Suffield Research Centre, (Ralston, Alberta, Canada), and their colleagues, Lorena Braid, Ph.D., at Aurora BioSolutions Inc. (Medicine Hat, Canada) and John E. Davies, D.Sc., at the University of Toronto, are among them.

They wondered whether an antibody's protective window could be extended using engineered MSCs as a delivery platform, believing these cells might constitute a renewable source that compensates for the antibody’s natural rate of degradation. They focused on Venezuelan equine encephalitis virus (VEEV), a mosquito-borne pathogen that affects humans and horses and can be used in bio-warfare. No licensed vaccine or antiviral agent currently exists to combat the infection in humans.

Using mice, the scientists compared the effectiveness of a traditional treatment made up of purified antibodies to one using antibodies generated by adding a gene encoding a humanized VEEV antibody (anti-VEEV) to human umbilical cord perivascular cells (HUCPVCs) – a rich source of MSCs.

"The results were eye-opening," Dr. Hu reported. "While the traditional antibody administration protected the animals for two or three days after administration, the engineered HUCPVC with the transgene encoding anti-VEEV protected the majority of the animals for 10 days, with protective antibody levels up to 38 days. In fact, 10 percent of the mice continued to secrete anti-VEEV three months later."

Dr. Nagata added, "Given the success of this study, we expect that HUCPVC-mediated gene therapy will provide a solution for a range of applications and biologics, including the delivery of additional medical countermeasures for biological and chemical defense purposes."

“This is the first study to describe engineered mesenchymal stromal cells as vehicles to deliver disease antibodies,” said Anthony Atala, M.D., Editor-in-Chief of STEM CELLS Translational Medicine and director of the Wake Forest Institute for Regenerative Medicine. “The advantages of this approach include that a single dose could potentially provide immunity.”


The full article, “Engineered mesenchymal cells improve passive immune protection against lethal Venezuelan equine encephalitis virus exposure,” can be accessed at