Vaccine 19 (2001) 3104–3115 Vaccination of Balb/c mice against experimental visceral leishmaniasis with the GP36 glycoprotein antigen of Leishmania donoani Edilma Paraguai de Souza a , Robson Roney Bernardo b , Marcos Palatnik c , Clarisa Beatriz Palatnik de Sousa a, * a Instituto de Microbiologia, ‘Prof. Paulo de Go ´es’, Uniersidade Federal do Rio de Janeiro (UFRJ), CCS, Cidade Uniersita ´ria, Ilha do Funda ˜o, CP 68040. CEP 21941 -590. Rio de Janeiro, Brazil b Escola de Quı ´mica, Rio de Janeiro, Brazil c Hospital Uniersita ´rio Clementino Fraga Filho -Faculdade de Medicina , UFRJ, Rio de Janeiro, Brazil Received 12 October 2000; received in revised form 3 January 2001; accepted 8 January 2001 Abstract Leishmania donoani GP36 glycoprotein is the main antigen of the FML Fucose Mannose Ligand (FML) complex specifically recognized by sera of kala-azar human patients. The GP36 was isolated by chemical elution +sonication and used for Balb/c mouse vaccination in combination with saponin, by the s.c. route, inducing a strong and specific protective effect against experimental visceral leishmaniasis shown by the increase of: specific IgG antibodies (82.6%), mainly IgG2a, the delayed type of hypersensitivity to promastigote lysate (37.8%, P 0.001), the in vitro cellular proliferative response to GP36 of ganglia lymphocytes (53.5%, P 0.005) and the decrease of liver parasite burden (68.1%, P 0.025). Saponin treated controls reacted significantly differently from GP36 vaccinated animals at all the assayed variables (P 0.05). GP36 induced significant protection against murine visceral leishmaniasis at concentrations commonly used for vaccination with recombinant antigens. © 2001 Elsevier Science Ltd. All rights reserved. Keywords: Murine visceral leishmaniasis; GP36 glycoprotein; Native antigen; Adjuvants; Saponin www.elsevier.com/locate/vaccine 1. Introduction Human visceral leishmaniasis or kala-azar is a severe disease, lethal if not treated soon after the onset of symptoms, caused by parasites of the Leishmania dono - ani complex. Clinical signs in humans include: malaise, anemia, hepato-splenomegaly, hypergammaglobuline- mia, fever, cachexia and progressive suppression of the cellular immune response. About 500000 human cases of kala-azar are registered annually. The disease devel- ops with endemic characteristics in Asia, Europe and America with important localized epidemic bursts. 90% of all human cases occur in Bangladesh, Brazil, India and Sudan. Between 1977 – 1987, 185000 new cases were registered in Bihar (India). 40000 obits due to the disease took place in Sudan and 400000 annual new cases with 5–7% fatality were reported in India [1]. In America, kala-azar is a canid zoonosis transmitted by sandflies. The control of canine kala-azar should there- fore reduce the availability of parasites to sandflies and thus reduce the human disease incidence [2]. The cur- rent strategy for control of kala-azar, as recommended by the World Health Organization (WHO), is based on detection and destruction or treatment of infected dogs, treatment of human cases and vector control [2]. Since the efficacy of this control has been shown to be inconsistent, the development of vaccines has been given priority and is considered to be urgent by the World Health Organization. First and second generation vaccines against leishma- niasis were primarily based on either of two technolo- gies from which antigenic material was derived. These * Corresponding author. Tel.: +55-21-5903093; fax: +55-21- 5608344/5608028. E-mail address: immgcpa@microbio.ufrj.br (C.B. Palatnik de Sousa). 0264-410X/01/$ - see front matter © 2001 Elsevier Science Ltd. All rights reserved. PII: S0264-410X(01)00031-7