Acta Parasitologica

, Volume 55, Issue 4, pp 304–312 | Cite as

Characterisation of NcGRA7 and NcSAG4 proteins: Immunolocalisation and their role in the host cell invasion by Neospora caninum tachyzoites

  • Adriana Aguado-Martínez
  • Gema Álvarez-García
  • Gereon Schares
  • Verónica Risco-Castillo
  • Aurora Fernández-García
  • Virginia Marugán-Hernández
  • Luis M. Ortega-Mora


Neospora caninum negatively impacts bovine reproductive performance around the world. Addressing this problem requires a greater understanding of the parasite’s molecular biology. In this study, monoclonal antibodies against recombinant proteins were successfully developed and employed to characterise two different proteins of N. caninum: the acute phase-associated NcGRA7 and the chronic phase-associated NcSAG4. Immunofluorescence with the anti-rNcGRA7 monoclonal antibody suggested that NcGRA7 trafficks from tachyzoite dense granules to the matrix of the parasitophorous vacuole and parasite’s surroundings. Furthermore, NcGRA7 is also expressed in the bradyzoite stage and localised on the matrix of bradyzoite-positive vacuoles. NcGRA7 appears to be partially involved in the tachyzoite-invasion mechanisms, as an anti-rNcGRA7 monoclonal antibody partially inhibited in vitro tachyzoite-invasion. A monoclonal antibody specific for NcSAG4 confirmed this protein’s bradyzoitespecific expression both by western blot and immunofluorescence. However, some bradyzoite-positive vacuoles only weakly expressed NcSAG4, if it was expressed at all. The specificity of the anti-rNcSAG4 monoclonal antibody was confirmed by the recognition of the NcSAG4 in the membrane surface of Nc-1SAG4c transgenic tachyzoites, which constitutively expresses NcSAG4. Blocking NcSAG4 of Nc-1SAG4c tachyzoites with the monoclonal antibody did not affect host cell invasion. However, its implication on the host cell adhesion or host immune evasion should not be discarded.


NcGRA7 NcSAG4 immunolocalisation invasion Neospora caninum tachyzoite bradyzoite monoclonal antibody 


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Copyright information

© © Versita Warsaw and Springer-Verlag Wien 2010

Authors and Affiliations

  • Adriana Aguado-Martínez
    • 1
  • Gema Álvarez-García
    • 1
  • Gereon Schares
    • 2
  • Verónica Risco-Castillo
    • 3
  • Aurora Fernández-García
    • 4
  • Virginia Marugán-Hernández
    • 1
  • Luis M. Ortega-Mora
    • 1
  1. 1.Grupo SALUVET, Departamento de Sanidad Animal, Facultad de VeterinariaUniversidad Complutense de MadridMadridSpain
  2. 2.Friedrich-Loeffler-Institut, Federal Research for Animal HealthInstitute of ParasitologyWusterhausenGermany
  3. 3.Institut National de la Santé et de la Recherche Médicale (INSERM)Unité Mixte de Recherche S945ParisFrance
  4. 4.Departamento de Biología y Variabilidad del VIH, CNMInstituto de Salud Carlos IIIMajadahonda, MadridSpain

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