EDINBURG ? Researchers at the Regional Academic Health Center here have taken a step toward improving a vaccine to combat a relentless disease.

Dr. Subramanian Dhandayuthapani, a microbiologist at The University of Texas Health Science Center at San Antonio's RAHC facility in Edinburg, and other researchers are studying methods to combat tuberculosis, which still flourishes on the Texas-Mexico border.

In a study published in the March issue of the journal Nature Medicine, the scientists identified a method that could make the only vaccine available for TB more effective.

The vaccine, called BCG, is rarely used in the United States because it's unpredictable and skews skin tests for TB, according to the Centers for Disease Control and Prevention.

Tuberculosis is an airborne disease that often affects the lungs, but also can infect the brain, spine or kidneys, according to the CDC.

Symptoms of active disease include weight loss, chills, fever, coughing up blood and chest pain, but many people who are exposed develop a latent form of the disease and have no symptoms.

The vaccine isn't always effective against TB because the bacteria is able to outsmart the body's immune system, said Dhandayuthapani, who is frequently called "Dr. Pani" by his colleagues. Essentially, it can stay latent in the body's cells so antibodies, produced by the vaccine, can't recognize it, he said.

The researchers used a drug called rapamycin, which prevents rejection of transplanted organs, to make the vaccine more effective in mice infected with TB. The drug helped make latent TB more visible to the body's immune system by inducing a process called autophagy, the researchers said. In autophagy, the TB cell digests part of itself, exposing the bacteria to antibodies.

Dhandayuthapani and his collaborators at The University of Texas Health Science Center at Houston, including associate pathology professor Chinnaswamy Jagannath, also found that a genetically modified form of the vaccine is more effective than the standard type against TB.

"BCG has been in use for a long time, but it's not very effective," Dhandayuthapani said. "We've improved it."

Scientists are still at least a few years away from developing an improved vaccine that could undergo human trials, he said.

But this research is a huge leap forward in developing a more potent vaccine against the highly contagious disease, said Thomas Slaga, interim director of the RAHC in Edinburg.

"This is a big boost (in research), and Dr. Pani's group has put a lot of effort into this," Slaga said.

Creating a better vaccine against TB could make a difference across the world, as well as in the Valley, Slaga said.

An estimated 1.5 million people died of TB in 2006, according to the World Health Organization. More than 9 million new cases were diagnosed.

In the Rio Grande Valley, Cameron County had 74 cases in 2007, the latest state data available. Hidalgo County had 76 cases. Starr and Willacy had 10 cases combined.

The border region is "the portal" for TB to enter the United States, Slaga said. That's why TB research here is important, he said.

"Whatever we do here will have implications for the rest of the world," he said.