Immunization against Leishmania donovani: glucan as an adjuvant with killed promastigotes.

Mice were immunized by a series of intravenous injections of formalin-killed Leishmania donovani promastigotes alone and combined with glucan, a beta 1,3 polyglucose derivative of baker's yeast. In three separate experiments animals were challenged with viable parasites on day 21, 40 or 80 after immunization. Mice which received dead parasites and glucan exhibited resistance against challenge up to 80 days after immunization. Animals which had been injected with glucan alone exhibited a lesser degree of resistance but injections of killed promastigotes alone conferred no measurable resistance against infection.