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Journal of Biomedicine and Biotechnology
Volume 2010 (2010), Article ID 181690, 9 pages
http://dx.doi.org/10.1155/2010/181690
Research Article

BALB/c Mice Vaccinated with Leishmania major Ribosomal Proteins Extracts Combined with CpG Oligodeoxynucleotides Become Resistant to Disease Caused by a Secondary Parasite Challenge

1Departamento de Biología Molecular, Centro de Biología Molecular Severo Ochoa, (CSIC-UAM), Nicolás Cabrera 1, Universidad Autónoma de Madrid, 28049 Madrid, Spain
2Unidad de Inmunología Viral, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Crta. Pozuelo Km 2, Majadahonda, 28220 Madrid, Spain
3Centro de Pesquisas Gonçalo Moniz, Fundação Oswaldo Cruz (FIOCRUZ), Rua Waldemar Falcao, 121, Candeal, 40.296-710 Salvador-Bahia, Brazil

Received 22 July 2009; Revised 11 September 2009; Accepted 29 October 2009

Academic Editor: Jorge Morales-Montor

Copyright © 2010 Laura Ramírez et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Leishmaniasis is an increasing public health problem and effective vaccines are not currently available. We have previously demonstrated that vaccination with ribosomal proteins extracts administered in combination of CpG oligodeoxynucleotides protects susceptible BALB/c mice against primary Leishmania major infection. Here, we evaluate the long-term immunity to secondary infection conferred by this vaccine. We show that vaccinated and infected BALB/c mice were able to control a secondary Leishmania major challenge, since no inflammation and very low number of parasites were observed in the site of reinfection. In addition, although an increment in the parasite burden was observed in the draining lymph nodes of the primary site of infection we did not detected inflammatory lesions at that site. Resistance against reinfection correlated to a predominant Th1 response against parasite antigens. Thus, cell cultures established from spleens and the draining lymph node of the secondary site of infection produced high levels of parasite specific IFN- in the absence of IL-4 and IL-10 cytokine production. In addition, reinfected mice showed a high IgG2a/IgG1 ratio for anti-Leishmania antibodies. Our results suggest that ribosomal vaccine, which prevents pathology in a primary challenge, in combination with parasite persistence might be effective for long-term maintenance of immunity.