Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine Dunia Rassy 1 , Rau ´ l J. Bobes 1 , Gabriela Rosas 2 , Victor H. Anaya 3 , Klaus Brehm 4 , Beatriz Herna ´ ndez 5 , Jacquelynne Cervantes 1 , Sau ´ l Pedraza 1 , Julio Morales 1 , Nelly Villalobos 6 , Aline S. de Aluja 6 , Juan P. Laclette 1 , Caris M. Nunes 7 , Germano F. Biondi 8 , Gladis Fragoso 1 , Marisela Herna ´ ndez 1 , Edda Sciutto 1 * 1 Departamento de Inmunologı ´a, Instituto de Investigaciones Biome ´dicas, Universidad Nacional Auto ´noma de Me ´xico, Distrito Federal, Me ´ xico, 2 Facultad de Medicina, Universidad Auto ´ noma del Estado de Morelos. Cuernavaca, Morelos, Me ´ xico, 3 Institute for Theoretical Biology, Humboldt Universita ¨t zu Berlin, Berlin, Germany, 4 Institut fu ¨ r Hygiene und Mikrobiologie, Julius-Maximillians-Universita ¨t Wu ¨ rzburg, Wu ¨ rzburg, Germany, 5 Facultad de Medicina, Universidad Nacional Auto ´noma de Me ´ xico, Distrito Federal, Me ´ xico, 6 Facultad de Medicina Veterinaria y Zootecnia, Universidad Nacional Auto ´ noma de Me ´ xico, Distrito Federal, Me ´ xico, 7 Departamento de Apoio, Produc ¸a ˜o e Sau ´ de Animal, Campus de Arac ¸atuba, Universidad Estadual Paulista ‘‘Ju ´ lio de Mesquita Filho, Arac ¸atuba, Sa ˜o Paolo, Brazil, 8 Departamento de Higiene Veterina ´ria e Sau ´de Pu ´ blica, Faculdade de Medicina Veterina ´ria e Zootecnia de Botucatu, Campus Botucatu, Universidad Estadual Paulista ‘‘Ju ´ lio de Mesquita Filho, Botucatu, Sa ˜o Paolo, Brazil Abstract Background: Cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in non-developed and developed countries. S3Pvac and EG95 are the only field trial-tested vaccine candidates against cysticercosis and hydatidosis, respectively. S3Pvac is composed of three peptides (KETc1, GK1 and KETc12), originally identified in a Taenia crassiceps cDNA library. S3Pvac synthetically and recombinantly expressed is effective against experimentally and naturally acquired cysticercosis. Methodology/Principal Findings: In this study, the homologous sequences of two of the S3Pvac peptides, GK1 and KETc1, were identified and further characterized in Taenia crassiceps WFU, Taenia solium, Taenia saginata, Echinococcus granulosus and Echinococcus multilocularis. Comparisons of the nucleotide and amino acid sequences coding for KETc1 and GK1 revealed significant homologies in these species. The predicted secondary structure of GK1 is almost identical between the species, while some differences were observed in the C terminal region of KETc1 according to 3D modeling. A KETc1 variant with a deletion of three C-terminal amino acids protected to the same extent against experimental murine cysticercosis as the entire peptide. On the contrary, immunization with the truncated GK1 failed to induce protection. Immunolocalization studies revealed the non stage-specificity of the two S3Pvac epitopes and their persistence in the larval tegument of all species and in Taenia adult tapeworms. Conclusions/Significance: These results indicate that GK1 and KETc1 may be considered candidates to be included in the formulation of a multivalent and multistage vaccine against these cestodiases because of their enhancing effects on other available vaccine candidates. Citation: Rassy D, Bobes RJ, Rosas G, Anaya VH, Brehm K, et al. (2010) Characterization of S3Pvac Anti-Cysticercosis Vaccine Components: Implications for the Development of an Anti-Cestodiasis Vaccine. PLoS ONE 5(6): e11287. doi:10.1371/journal.pone.0011287 Editor: David Joseph Diemert, The George Washington University Medical Center, United States of America Received December 23, 2009; Accepted June 2, 2010; Published June 23, 2010 Copyright: ß 2010 Rassy et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was funded by the Consejo Nacional de Ciencia y Tecnologia S52680-R/70072, CB-62471 and Direccion General de Asuntos del Personal Academico (DGAPA) IN217908. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript. Competing Interests: The authors have declared that no competing interests exist. * E-mail: edda@servidor.unam.mx Introduction Parasitic zoonoses such as cysticercosis and hydatidosis seriously affect human health and are responsible for considerable economic loss in animal husbandry in developing and developed countries [1]. Cestode lifecycles were established in their respective hosts during the Pleistocene or earlier [2], and such long coexistence has evolved into an intricate, multifaceted relationship. To interrupt transmission of disease-causing cestodes to humans, simultaneous and sustained implementation of far-reaching measures and comprehensive social programs are required. These include devising and implementing specific and general health education programs, improving living conditions, and treating tapeworm carriers, among others. Vaccination represents an additional tool for control and prevention. Various whole or subunit vaccine candidates have been tested with promising protective effects against cysticercosis due to T. solium and T. saginata, and against hydatid disease caused by E. granulosus and E. multilocularis [3–10]. Their effectiveness, however, has been assessed mostly in controlled experimental environments rather than in complex natural conditions. Additionally, renewed hope on the successful formulation of vaccines for the prevention of PLoS ONE | www.plosone.org 1 June 2010 | Volume 5 | Issue 6 | e11287