Texas T-cells trained to kill viruses

Texas scientists have developed a method to extract virus-killing "T-cells" and induce them to attack 3 types of viruses, cytomegalovirus, Epstein-Barr virus, and adenovirus. The cells can then be placed back in the body of the original patient.

This technique is useful in the care for patients after bone marrow transplants, when the patient is especially susceptible to infection. T-cells are a group of white blood cells that help fight infection, especially viral infections. Most of us would never notice these infections or become only slightly ill with "Mono," a "stomach bug," cold symptoms, or "pink eye" before our own T-cells learned to attack and control the multiplication of the virus. In transplant patients, however the infections are life-threatening.

(In fact, the next time you donate blood, look at the report you get back: most adults are "CMV positive." Their blood will not be used to transfuse CMV negative pregnant women, immunocompromised patients or sick children, but is not a problem in most adults.)


Science Daily reports on the success of researchers at Baylor College of Medicine, The Methodist Hospital, and Texas Children's Hospital in Houston, Texas in developing the technique resulting in Trivirus-specific cytotoxic T lymphocytes (CTLs).

"Not only were patients prevented from getting these infections after transplant, but those patients who had infections responded to the T-cell therapy and did not require any other treatment," said senior author Dr. Catherine Bollard, assistant professor of pediatrics, immunology, and medicine at BCM and a researcher at the Center for Cell and Gene Therapy at BCM, Methodist and Texas Children's. "To make dramatic recoveries like these was really quite something."

The research team drew cells from bone marrow donors and "trained" T-cells to target the three viruses before injecting them into transplant recipients.

"Drugs only control the virus. They don't cure the underlying problem," said Bollard. "Whereas by introducing these specialized T-cells, we are fixing the underlying problem. Using your own immune system is preferable to chemical agents, which can have toxic side effects."

Although the CTLs must undergo further testing, the early results suggest the combination therapy to be more, cost-effective, and safe than traditional therapies and more practical than cell-based therapies that target EBV and CMV separately, both of which are carried in roughly 80 percent of all people. Adenoviruses are common viruses carried in all populations.

"There is no safe and effective therapy for patients with adenovirus infections at the moment, so if you get an infection after a transplant it becomes very problematic," said first author Dr. Ann Leen, BCM instructor of pediatrics at the Center for Cell and Gene Therapy. "So we trained certain T-cells to target this virus."

Bollard envisions one day extending the application of CTLs to other people with compromised immune systems, such as cancer patients undergoing chemotherapy. The therapy could also potentially be used in babies, who are more susceptible to adenovirus infections than other age groups.