Scientists develop potential new TB vaccine

WASHINGTON, Jan. 13 (UPI) -- Researchers are working on a potential new tuberculosis vaccine that would be the first new TB vaccine in a century to combat drug-resistance.

The new vaccine uses biobeads to place antigens from the tuberculosis bacterium into the body's immune system. Biobeads are natural polyesters that non-tuberculosis bacteria, in this case E. coli, assemble into small spheres.

Researchers have been able to engineer the biobeads to show antigens from tuberculosis bacteria, Mycobacterium tuberculosis or Mycobacterium bovis.

Mycobacterial antigens on biobeads can induce cell-mediated immune responses in laboratory mice.

"From these observations, we developed the hypothesis that these proteins could also function as antigens," Axel Helser, Ph.D., senior scientist, AgResearch Ltd., said in press release. "If produced in Mycobacteria instead of E.coli, such bioheads should carry mycobacterial antigens on their surface, including many as yet undiscovered antigens which would have the potential to induce protective immunity."

However, Mycobacteria do not have the enzymes needed to make biobeads, so researchers developed new cloning techniques that allowed for expression of the enzymes in M. smegmatis, a mycobacterium that does not cause tuberculosis.

"We killed and broke up the bacteria, and purified the biobeads," Heiser said. "They are completely natural, and have been shown to be biodegradable. We then used these mycobacterial biobeads to vaccinate mice and tested the mice for immune responses. We saw evidence of cell-mediated immunity with the potential to be protective against TB."

The current TB vaccine was created in 1921 and can cause the disease in people with compromised immune systems.

The study was published in Applied and Environmental Microbiology.