Oral subunit vaccine protects against tuberculosis in experiment

Copenhagen researchers say oral vaccine containing M. tuberculosis antigens and adjuvant, when given to mice and guinea pigs, triggers a type I immune response

Research results show that booster vaccination with this vaccine can be effective in preventing pulmonary tuberculosis in adults who already have immunity due to primary BCG vaccination.

About 10 years after the BCG vaccination, the effect of the vaccine is weakened and the person becomes susceptible to tuberculosis again. The residual effect of the introduction of the BCG vaccine remains and subsequent booster vaccination with a live vaccine prevents replication of M. bovis.

In search of the best vaccination methodology, researchers from the Statens Serum Institute conducted a study of the immunogenic properties of the oral subunit vaccine. The study presented data on a vaccine containing two immunogenic antigens M. tuberculosis and the monophosphoryl lipid A (IFF) neutralized. The safety of IFF as an adjuvant that elicits a persistent cell-mediated immune response due to active production of pro-inflammatory cytokines by antigen-presenting cells has been confirmed in human studies.

The researchers found that in an experiment in mice, an oral vaccine does not cause a persistent primary immune response. However, a single subcutaneous administration of a vaccine followed by an oral dose causes a rapid increase in the number of CD4 cells producing interferon gamma.

In addition, immunity from oral vaccination in mice and pigs results in a significant reduction in the likelihood of infection compared to unvaccinated animals.

Researchers believe this strategy can be used to vaccinate people in the future.