Oral Delivery ofMycobacterium bovisBCG in a Lipid Formulation Induces Resistance to Pulmonary Tuberculosis in Mice

Abstract

A lipid-based formulation has been developed for oral delivery ofMycobacterium bovisbacille Calmette-Guérin (BCG) vaccine. The formulatedM. bovisBCG was fed to BALB/c mice to test for immune responses and protection againstM. bovisinfection. The immune responses included antigen-specific cytokine responses, spleen cell proliferation, and lymphocyte-mediated macrophage inhibition ofM. bovis. Oral delivery of formulatedM. bovisBCG to mice induced strong splenic gamma interferon levels and macrophage inhibition of virulentM. boviscompared with results with nonformulatedM. bovisBCG. Formulated oralM. bovisBCG significantly reduced the bacterial burden in the spleen and lungs of mice following aerosol challenge with virulentM. bovis. Our data suggest that oral delivery of formulatedM. bovisBCG is an effective means of inducing protective immune responses against tuberculosis. Lipid-based, orally delivered mycobacterial vaccines may be a safe and practical method of controlling tuberculosis in humans and animals.