Arch Dermatol Res (2012) 304:47–55 DOI 10.1007/s00403-011-1171-7 123 ORIGINAL PAPER Analysis of the protective potential of antigens released by Leishmania (Viannia) shawi promastigotes Luiz Felipe Domingues Passero · Cláudia Marques · Inês Vale-Gato · Carlos Eduardo Pereira Corbett · Márcia Dalastra Laurenti · Gabriela Santos-Gomes Received: 7 April 2011 / Revised: 12 August 2011 / Accepted: 17 August 2011 / Published online: 1 September 2011  Springer-Verlag 2011 Abstract Leishmania (Viannia) shawi causes cutaneous lesions in humans. Parasite antigens conferring signiWcant protection against American tegumentar leishmaniosis (ATL) might be important for the development of eVective vaccine. Therefore, this work evaluates the protective eVect of antigenic fractions released by L. shawi. Antigens released by promastigotes to culture medium were concen- trated and isolated by SDS-PAGE. The three main fractions LsPass1 (>75 kDa), LsPass2 (75–50 kDa) and LsPass3 (<50 kDa) were electro-eluted according with their molecu- lar mass. Immunized BALB/c mice were challenged with L. shawi promastigotes and the course of infection moni- tored during 5 weeks. LsPass1-challenged mice showed no protection, however, a strong degree of protection associ- ated to smaller lesions and high expression of IFN- and TNF- by CD4 + T, CD8 + T and double negative CD4CD8 cells was achieved in LsPass3-challenged mice. Further- more, LsPass2-challenged mice showed an intermediated degree of protection associated to high levels of IFN-, IL-4 and IL-10 mRNA. In spite of increased expression of IFN- and TNF-, high amounts of IL-4 and IL-10 mRNA were also detected in LsPass3-challenged mice indicating a pos- sible contribution of these cytokines for the persistence of a residual number of parasites that may be important in inducing long-lasting immunity. Therefore, LsPass3 seems to be an interesting alternative that should be considered in the development of an eVective vaccine against ATL. Keywords Leishmania shawi · Released antigens · Immunization · Immune response Introduction Leishmaniosis are diseases caused by the parasite of the genus Leishmania. This parasite infects a broad range of mammalian species, generating tegumentar or visceral leishmaniosis. Although over 27 species of Leishmania have been identiWed worldwide, there are some species recently identiWed in New World. Studies able to under- stand the dynamics of epidemiology and the immune-path- ogenesis of these newly identiWed species are scarce [11, 13, 14, 37, 38]. Leishmania (Viannia) shawi was described by Lainson and collaborators in 1989 [13] in non-human primates from Pará State, Brazil, and recognized as pathogenic to humans 2 years after [37]. Furthermore, Brito and collaborators [2] described Wve new L. shawi isolates obtained from clinical cases identiWed in Pernambuco State suggesting that this parasite may have a non-negligible epidemiological impor- tance in Brazil. Recently, our group has characterized the murine model of L. shawi infection [27], evaluating cellular and humoral immune responses in infected BALB/c mice to better clarify the main immunological alterations induced L. F. D. Passero · C. E. P. Corbett · M. D. Laurenti Laboratório de Patologia de Moléstias Infecciosas, Faculdade de Medicina, Universidade de São Paulo, São Paulo, Brazil C. Marques · I. Vale-Gato · G. Santos-Gomes Unidade de Ensino e Investigação de Parasitologia Médica, Centro de Malária e outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Lisbon, Portugal G. Santos-Gomes (&) Unidade de Ensino e Investigação de Parasitologia Médica, Instituto de Higiene e Medicina Tropical (IHMT), Centro de Malária e Outras Doenças Tropicais, Rua da Junqueira 100, 1349-008 Lisbon, Portugal e-mail: santosgomes@ihmt.unl.pt