In vivo and in vitro expression pattern of Toll-like receptors in Mycobacterium avium subspecies paratuberculosis infection.
Vet Immunol Immunopathol
; 156(1-2): 20-31, 2013 Nov 15.
Article
em En
| MEDLINE
| ID: mdl-24054090
ABSTRACT
Johne's disease (JD) caused by Mycobacterium avium subspecies paratuberculosis (MAP) is a chronic infectious disease of ruminants. Activation of the Toll-like receptors (TLR) in response to microbial stimuli, including MAP, initiates responses in immune cells of the blood and within peripheral tissues. TLR2, 4 and 9 are believed to play a critical role in the initiation of immune responses against mycobacteria. In this study we report on the in vivo expression pattern of these receptors in sheep and cattle experimentally exposed to MAP. Experiments using the mouse macrophage cell line, RAW 264.7, and on isolated bovine monocytes were also carried out to assess the expression pattern of TLR2 and 4 in response to MAP and the non-pathogenic mycobacterial strain, M. smegmatis. Results from the in vivo study showed that there was a significant upregulation of TLR2 (P<0.05) at early time-points post-inoculation in the peripheral blood cells of sheep exposed to MAP S strain that went on to develop severe (multibacillary) disease. However, in the cattle during the initial months post-exposure to MAP C strain, TLR2 was significantly downregulated (P<0.05). TLR4 was significantly upregulated (P<0.05) at later stages (12 months post-inoculation) in MAP-exposed sheep with multibacillary disease; however significant differences in TLR4 expression were not observed in cattle. Expression of TLR9 was unchanged in MAP-exposed sheep and cattle. In vitro studies on mouse macrophages supported the findings of in vivo TLR2 gene expression increases seen in the sheep, in that the TLR2 receptor expression in response to MAP-infection was significantly increased in comparison to cells infected with a non-virulent mycobacterium, M. smegmatis. A likely role for TLR2 in the pathogenesis of Johne's disease is proposed.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Paratuberculose
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Doenças dos Ovinos
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Doenças dos Bovinos
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Receptores Toll-Like
Tipo de estudo:
Etiology_studies
Limite:
Animals
Idioma:
En
Revista:
Vet Immunol Immunopathol
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
Austrália