Successful vaccination against Leishmania donovani infection in Indian langur using alum-precipitated autoclaved Leishmania major with BCG

Citation
A. Misra et al., Successful vaccination against Leishmania donovani infection in Indian langur using alum-precipitated autoclaved Leishmania major with BCG, VACCINE, 19(25-26), 2001, pp. 3485-3492
Citations number
38
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Veterinary Medicine/Animal Health",Immunology
Journal title
VACCINE
ISSN journal
0264-410X → ACNP
Volume
19
Issue
25-26
Year of publication
2001
Pages
3485 - 3492
Database
ISI
SICI code
0264-410X(20010514)19:25-26<3485:SVALDI>2.0.ZU;2-#
Abstract
Autoclaved Leishmania major (ALM) along with BCG, presently undergoing phas e II clinical trial by WHO for its vaccine potential against cutaneous leis hmaniasis, has been successfully evaluated in single and triple dose schedu les against L. donovani in Indian langurs (Presbytis entellus). Encouraged with the results, another formulation alum-precipitated ALM (provided by WH O) along with BCG has been evaluated in this system. Eight monkeys were vac cinated with alum-precipitated ALM + BCG (1 mg of each per animal) while fo ur were kept as unvaccinated controls. All were challenged with 100 x 10(6) amastigotes i.v. on day 60 post vaccination. Parasitic assessment in splen ic tissue was performed on day 45, 90 and 180 p.c. Initially, seven of the eight vaccinated monkeys developed infection (two to six amastigotes per 10 00 cell nuclei), which resolved by day 180 p.c., while the eighth monkey ha d a parasite burden of 14 amastigotes per 1000 cell nuclei on day 45 p.c. a nd died on day 130 p.c. On the other hand, there was progressive infection in unvaccinated control animals and three out of four died between days 110 and 120 p.c., and one monkey, which had low parasite burden, died on day 1 78 p.c. Prior to challenge, there was an initial rise in antileishmanaial a ntibodies in the vaccinated group compared to the unvaccinated control grou p, which later came down to normal level, while it remained higher in the u nvaccinated control group. An increasing pattern of antigen-specific prolif erative responses and interferon-gamma level to the two antigens - autoclav ed L. donovani (ALD) and ALM - was observed in vaccinated monkeys throughou t the experiment. There was a good correlation between parasite burden and IFN-gamma level on days 90 and 180 p.c., indicating IFN-gamma response as a sensitive parameter of immune status. The findings suggest alum-precipitat ed ALM + BCG as a potential vaccine against visceral leishmaniasis and warr ants clinical trials. (C) 2001 Elsevier Science Ltd. All rights reserved.