Stem cells genetically engineered to carry a molecule (derived from an HIV-infected person) that recognizes the virus could provide a new way to bolster the immune system against the disease, according to new research published this week in PLoS ONE. When implanted into mice, the stem cells developed into mature immune cells that could target cells with HIV specific proteins. Researchers are using a similar approach to prime the human immune system against cancer.

"We have 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," says lead investigator Scott G. Kitchen, an 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, in a press release. "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."

According to the release:

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.

Researchers hope the technology will have broader applications."This approach could be used to combat a variety of chronic viral diseases," says co-author Jerome A. Zack, a UCLA professor of medicine in the division of hematology and oncology and associate director of the UCLA AIDS Institute, in the same release. "It's like a genetic vaccine."

The beautiful city of San Francisco, where I recently moved to cover materials science for TR, would most certainly benefit from a public-health campaign aimed at preventing its citizens from spitting onto the sidewalks. In this context, mucus is gross. But let's move past that for a moment, for surely mucus is worthy of our praise. The protective coatings that line tissues including those inside the mouth, lungs, and reproductive tract are part of the body's first line of defense against infection. Mucus traps viruses, bacteria, and other particles, preventing them from penetrating into the body's tissues. It's not foolproof--we still get sick. So researchers at Johns Hopkins University are working on treatments that temporarily improve the mucus barrier's ability to keep out particles.

Mucus is made up of a mesh of proteins called mucins. The Hopkins team found that mucin strands tend to clump together, creating holes through which pathogens and pollutants can travel. When they used a detergent to disrupt some of this bundling, the researchers decreased the size of the holes so that particles as small as 200 nanometers in diameter were trapped in the mucin mesh. The researchers caution that this hasn't been tested in people, but they say those who work in places where there are high levels of unhealthy nanoparticles in the air, such as mines, might be protected by inhaling an aerosolized detergent. A similar aerosol might help protect caregivers during an influenza outbreak. Because the mucus is constantly sloughed off and replaced--as when your fellow citizens spit on the sidewalk--the effects of the treatment would last only hours at most.

This research is described in the journal PLoS One.

Watch non-adhesive coated latex beads, each 200 nanometers wide, travel through untreated and treated mucus.

Video courtesy of Public Library of Science One