title: Natural and induced antibodies contribute to differential susceptibility to secondary cystic echinococcosis of Balb/c and C57Bl/6 mice.
abstract: Antibodies are key immune players in several helminth infections and animal models have been central for the identification of their mechanisms of protection. Murine secondary cystic echinococcosis is a useful model for studying Echinococcus granulosus immunobiology, being the immune profile mounted by the experimental host a determinant of parasite success or failure in infection establishment. In the present study, we analyzed infection outcome using Balb/c and C57Bl/6 mice strains, and compared their antibody responses in terms of quality and intensity. Our results showed that Balb/c is a highly susceptible strain to secondary cystic echinococcosis, while C57Bl/6 mice are quite resistant. Moreover, significant differences between strains were observed in natural and induced antibodies recognizing E. granulosus antigens, both at the systemic and peritoneal levels. Natural cross-reacting IgM, IgG2b and IgG3 antibodies were detected in sera from both strains but with different intensities, and - remarkably - natural IgG2b showed to be an intrinsic correlate of protection in both mice strains. Interestingly, naïve C57Bl/6 serum displayed a higher protoscolicidal activity, and heterologous - but not homologous - transference of C57Bl/6 naïve serum into Balb/c mice, significantly reduced their infection susceptibility. In the peritoneal cavity, different levels of natural cross-reacting IgM and IgG3 antibodies were detected in both mice strains, while cross-reacting IgG2b was detected only in C57Bl/6 mice. On the other hand, infected mice from both strains developed isotype-mixed antibody responses, with Balb/c mice biasing their response towards high avidity IgG1 and C57Bl/6 mice showing a predominance of mixed IgM/IgG2c/IgG2b/IgG3. In this regard, IgG1 levels showed to be a correlate of susceptibility in both mice strains. In conclusion, our results suggest that antibodies - either natural or induced - play a role in the susceptibility degree to murine secondary cystic echinococcosis.
authors.affiliation: Cátedra de Inmunología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Avda Alfredo Navarro 3051, piso 2, CP 11600 Montevideo, Uruguay. Electronic address: gmourglia@higiene.edu.uy.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Mourglia-Ettlin
authors.affiliation: Instituto de Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Paraguay 2155, piso 13, C1121ABG Buenos Aires, Argentina. Electronic address: marcecucher@gmail.com.
authors.forename: Marcela
authors.initials: M
authors.lastname: Cucher
authors.affiliation: Cátedra de Inmunología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Avda Alfredo Navarro 3051, piso 2, CP 11600 Montevideo, Uruguay. Electronic address: parbildi@higiene.edu.uy.
authors.forename: Paula
authors.initials: P
authors.lastname: Arbildi
authors.affiliation: Instituto de Microbiología y Parasitología Médica, Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Tecnológicas (IMPaM, UBA-CONICET), Paraguay 2155, piso 13, C1121ABG Buenos Aires, Argentina. Electronic address: mararosenzvit@gmail.com.
authors.forename: Mara
authors.initials: M
authors.lastname: Rosenzvit
authors.affiliation: Cátedra de Inmunología, Departamento de Biociencias, Facultad de Química, Universidad de la República, Avda Alfredo Navarro 3051, piso 2, CP 11600 Montevideo, Uruguay. Electronic address: sdemat@fq.edu.uy.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Dematteis
mesh_terms: D019264:Adoptive Transfer; D000818:Animals; D000909:Antibodies, Helminth / Q000097:blood*; D000947:Antigens, Helminth / Q000097:blood / Q000276:immunology*; D003429:Cross Reactions; D004198:Disease Susceptibility / Q000276:immunology*; D004443:Echinococcosis / Q000276:immunology* / Q000469:parasitology; D048209:Echinococcus granulosus / Q000276:immunology*; D005260:Female; D058507:Host Specificity; D056724:Immunity, Humoral; D007074:Immunoglobulin G / Q000097:blood; D007075:Immunoglobulin M / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL
chemical_list: D000909:Antibodies, Helminth; D000947:Antigens, Helminth; D007074:Immunoglobulin G; D007075:Immunoglobulin M
keywords: Balb/c; C57Bl/6; Echinococcus granulosus; Natural antibodies; Resistance; Susceptibility