The investigational vaccine for TB tested at the university appears likely to offer significantly better protection against the potentially fatal disease than the one in current use.
"Not only was it as safe as the standard vaccine, it induced a better immune response, which suggests it will be more effective at protecting against tuberculosis," said Daniel Hoft, M.D., Ph.D., director of the division of immunobiology at Saint Louis University School of Medicine and lead author of the study.
The investigational vaccine is made from a weakened TB germ from one of the strains of the current tuberculosis vaccine, which was created more than 75 years ago.
The new "recombinant" vaccine uses an antigen, a secreted protein from a virulent strain of tuberculosis, to help focus the immune system on blocking aggressive and deadly TB organisms.
In this phase I clinical trial, researchers vaccinated a total of 35 study participants. The standard TB vaccine - called Bacille Calmette-Guérin (BCG) - was given to 17 study participants, and 18 study participants received the investigational recombinant BCG vaccine.
Researchers compared five immune functions induced by the vaccines and found that the investigational vaccine induced more powerful responses that are important for protection against tuberculosis. The investigational vaccine also was safe and well tolerated.
The study has shown that the concept of using a recombinant vaccine holds promise in being able to better protect people from tuberculosis.
This vaccine will not be tested further because it uses an antibiotic resistant gene that scientists want to keep out of the environment.
However research in this area will continue as scientists test a similar recombinant BCG vaccine that expresses the same and additional key TB antigens that is expected to be even more potent than the one just studied and does not include the antibiotic resistant gene, Hoft said.
"A new vaccine theoretically could not only protect against the overwhelming growth of TB organisms, but could kill residual organisms after a person has become infected. That's the hope," Hoft said.
The study appears in the Journal of Infectious Diseases.