VtaA8 and VtaA9 from Haemophilus parasuis delay phagocytosis by alveolar macrophages
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Publication date
2012-07-27ISSN
0928-4249
Abstract
Haemophilus parasuis, a member of the family Pasteurellaceae, is a common inhabitant of the upper respiratory tract
of healthy pigs and the etiological agent of Glässer’s disease. As other virulent Pasteurellaceae, H. parasuis can
prevent phagocytosis, but the bacterial factors involved in this virulence mechanism are not known. In order to
identify genes involved in phagocytosis resistance, we constructed a genomic library of the highly virulent
reference strain Nagasaki and clones were selected by increased survival after incubation with porcine alveolar
macrophages (PAM). Two clones containing two virulent-associated trimeric autotransporter (VtaA) genes, vtaA8
and vtaA9, respectively, were selected by this method. A reduction in the interaction of the two clones with the
macrophages was detected by flow cytometry. Monoclonal antibodies were produced and used to demonstrate
the presence of these proteins on the bacterial surface of the corresponding clone, and on the H. parasuis
phagocytosis-resistant strain PC4-6P. The effect of VtaA8 and VtaA9 in the trafficking of the bacteria through the
endocytic pathway was examined by fluorescence microscopy and a delay was detected in the localization of the
vtaA8 and vtaA9 clones in acidic compartments. These results are compatible with a partial inhibition of the routing
of the bacteria via the degradative phagosome. Finally, antibodies against a common epitope in VtaA8 and VtaA9
were opsonic and promoted phagocytosis of the phagocytosis-resistant strain PC4-6P by PAM. Taken together,
these results indicate that VtaA8 and VtaA9 are surface proteins that play a role in phagocytosis resistance of
H. parasuis.
Document Type
Article
Document version
Published version
Language
English
Subject (CDU)
619 - Veterinary science
Pages
10
Publisher
BMC
Is part of
Veterinary Research
Citation
Costa-Hurtado, Mar, María Ballester, Núria Galofré-Milà, Ayub Darji, and Virginia Aragón. 2012. “VtaA8 and VtaA9 From Haemophilus Parasuis Delay Phagocytosis by Alveolar Macrophages.” Veterinary Research 43 (1): 57. doi:10.1186/1297-9716-43-57.
Grant agreement number
MICINN/Programa Nacional de Proyectos de Investigación Fundamental/AGL2010-15232/ES/SELECCION DE CANDIDATOS VACUNALES PARA BLOQUEAR LOS PASOS INICIALES DE LA INFECCION POR HAEMOPHILUS PARASUIS/
Program
Sanitat Animal
This item appears in the following Collection(s)
- ARTICLES CIENTÍFICS [2831]
Except where otherwise noted, this item's license is described as http://creativecommons.org/licenses/by/4.0/