Prophylactic potential of autoclaved Leishmania donovani with BCG against experimental visceral leishmaniasis
Srivastava, J.K.; Misra, A.; Sharma, P.; Srivastava, B.; Naik, S.; Dube, A.
Parasitology 127(Pt 2): 107-114
2003
ISSN/ISBN: 0031-1820 PMID: 12954011 DOI: 10.1017/s0031182003003457Document Number: 234444
The prophylactic efficacy of autoclaved Leishmania donovani (ALD) and autoclaved L. major (ALM; a heterologous vaccine developed against cutaneous leishmaniasis; used as a reference vaccine) along with BCG was evaluated against L. donovani in hamsters (Mesocricetus auratus). Animals were immunized with triple doses (21 days apart) of either ALD or ALM (1.0 mg) with or without BCG (0.1 mg) and challenged 21 days later with 1x106L. donovani amastigotes intracardially. Animals immunized with ALM + BCG and ALD + BCG yielded 94.3 and 86.1% parasite inhibition, respectively, in comparison to the BCG only and unvaccinated controls. 50 and 33.3% of the vaccinated animals (ALM + BCG and ALD + BCG, respectively) were completely devoid of parasites when tested on day 45 postchallenge and survived till the experiment was terminated. The mean survival of ALM + BCG and ALD + BCG groups (animals harbouring parasites) was longest (168 and 139 days, respectively). No significant increase in anti-leishmanial antibody level (ELISA) was noticed in ALD + BCG and ALM + BCG groups whereas it increased progressively in the rest of the experimental groups. The lymphoproliferative responses to phytohaemagglutinin and concanavalin A of the 2 vaccinated groups were comparable to that of normal controls on day 45 postchallenge. The study suggests that ALD along with BCG can offer substantial protection against visceral leishmaniasis in hamsters.