Available online at www.sciencedirect.com Chemistry and Physics of Lipids 152 (2008) 86–94 Use of proteoliposome as a vaccine against Trypanosoma cruzi in mice Vanessa Migliaccio a , Fabiana R. Santos a , Pietro Ciancaglini b,∗,1 , F. Juarez Ramalho-Pinto a,1 a Departamento de Bioqu´ ımica e Imunologia, Faculdade de Medicina de Ribeir˜ ao Preto, Universidade de S˜ ao Paulo, 14049-900 S˜ ao Paulo, Brazil b Departamento de Qu´ ımica, Faculdade de Filosofia Ciˆ encias e Letras de Ribeir˜ ao Preto, Universidade de S˜ ao Paulo, 14040-901 S˜ ao Paulo, Brazil Received 17 August 2007; received in revised form 20 December 2007; accepted 27 December 2007 Available online 6 January 2008 Abstract We have generated proteoliposomes carrying proteins of Trypanosoma cruzi for use as immunogens in BALB/c mice. T. cruzi trypomastigote and amastigote forms were sonicated and mixed with SDS, with 94% recovery of soluble proteins. To prepare proteoliposomes, we have used a protocol in which dipalmitoylphosphatidylcholine, dipalmitoyl-phosphatidylserine and cholesterol were incubated with the parasite proteins. BALB/c mice immunized with 20 g were able to generate antibodies which, in Western blotting, reacted with the proteins of T. cruzi. We further investigated the ability of peritoneal cells from immunized mice to arrest the intracellular replication of trypomastigotes, in vitro. After 72 h of culture, the number of intracellular parasites in immunized macrophages decreased significantly, as compared to controls. Despite the fact that exposure of mice to T. cruzi proteins incorporated into proteoliposomes generate antibodies and activate macrophages, the immunized mice were not protected against T. cruzi intraperitoneal challenge. © 2008 Elsevier Ireland Ltd. All rights reserved. Keywords: Trypanosoma cruzi; Detergent; Membrane proteins; Lipids; Proteoliposomes 1. Introduction American trypanosomiasis, or Chagas’ disease, is caused by Trypanosoma cruzi, a hemoflagellate protozoan parasite that infects humans and a wide variety of mammals (Burleigh and Woolsey, 2002). Although the infected host develops specific cellular and antibody-mediated immune responses, the chronic phase of this infection is maintained by a significant myocarditis associated with tissue parasitism (Brener and Gazzinelli, 1997). Throughout its life cycle, the parasite differentiates from meta- cyclic trypomastigote into the intracellular amastigotes form (Guarner et al., 2001) and expresses a large variety of mem- brane proteins that play an important role in the adhesion and invasion of the parasite in the host cells (Andrews et al., 1987). In vaccination trials, many of these membrane proteins recov- ered from live T. cruzi have been shown to elicit a protective immune response in animal models (Frank et al., 2003; Bhatia and Garg, 2005). ∗ Corresponding author. Tel.: +55 16 36023753; fax: +55 16 36024838. E-mail address: pietro@ffclrp.usp.br (P. Ciancaglini). 1 These authors contributed equally to this work. Recent studies have demonstrated the importance of CD4+ and CD8+ T-cell responses in the immunity to T. cruzi (Hoft et al., 2000; Hoft and Eickhoff, 2002; Ara´ ujo et al., 2005; De Alencar et al., 2007). The attention is now being directed toward antigens that elicit cell-mediated immune responses and would result in the immune recognition of parasite-infected host cells (Miller et al., 1996; Low et al., 1998). Hypothetically, a favorable immune response would have the capacity to trigger cytokine synthesis by den- dritic cells and macrophages, favoring the differentiation of Th cells into the Th1 phenotype, supposedly impor- tant for resistance to T. cruzi infection (Gazzinelli et al., 1993). The reconstitution of membrane proteins into liposomes, lipid vesicles constituted by one or more lipid layers, has been shown to be a useful tool to prepare antigenic components to induce immunity in experimental models (Kita et al., 2005; Santos et al., 2006). Liposomes have been shown to serve as appropriate antigen carriers for the generation of antibody response in vivo and effective vehicles for peptides and pro- teins, thus enhancing their immunogenicity (Brewer et al., 1998; Ignatius et al., 2000). Regarding cellular immune responses, 0009-3084/$ – see front matter © 2008 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.chemphyslip.2007.12.003