The role of BCG in human immune responses induced by multiple injections of autoclaved Leishmania major as a candidate vaccine against leishmaniasis

To determine if BCG was required in booster injections for autoclaved Leishmania major (ALM) vaccine, 75 volunteers with no response to leishmanin were injected double-blind and randomly with either ALM+BCG or BCG alone for the first injection and boosted either with ALM+BCG, ALM or BCG alone for the second and third. Addition of BCG to the boosters significantly increased the frequency and the magnitude of leishmanin skin tests (LSTs); however, there was no difference in proliferative and IFN-γ responses (a month and a year later). Three injections of BCG produced no observable adverse reaction; hence BCG could be used in booster injections to increase the protective potential of this candidate vaccine.