Local assessment of WC1+ γδ T lymphocyte subset in the different types of lesions associated with bovine paratuberculosis

6 páginas, 4 figuras.
The local expression of WC1 γδ T lymphocytes subset has been evaluated by immunohistochemical methods at the different types of lesions present in cows naturally infected with Mycobacterium avium subsp. paratuberculosis (Map) and in non-infected control animals. Infected cattle were either in the latent/subclinical (focal lesions) or clinical (diffuse paucibacillary and multibacillary forms) stage of paratuberculosis. To assess the cell distribution, a differential cell count was carried out at the lamina propria, gut-associated lymphoid tissue and submucosa. A significant increase in the number of WC1 γδ T cells was observed in all the infected animals, regardless of the type of lesion. Cows with focal lesions showed higher number of labeled cells than those with diffuse forms, where no differences were found between the two types. This increase in the number of positively immunolabelled lymphocytes in infected animals was seen in the lamina propria, with higher values in those with focal lesions. While in the lymphoid tissue no differences in the numbers were observed, in animals with focal lesions, WC1 γδ T cells tended to be located at the periphery of the granulomas. These findings suggest a proinflammatory action of WC1 γδ T lymphocytes in bovine paratuberculosis, which might play an important role in the containment of the Map-infection in the focal granulomas located in the lymphoid tissue, helping to prevent the progression toward diffuse forms responsible for the clinical signs.
This study was funded by grant AGL2015-66540-C2-1-R from de Spanish Ministry of Economy and Competitiveness and LE259/P18 from “Junta de Castilla y León”. N. Arteche and R. Vallejo are supported by a predoctoral contract from the Spanish Ministry of Economy and Competitiveness, or Education, respectively. J. Espinosa and D. Gutiérrez are the recipients of a postdoctoral contract of “Junta de Castilla y León-Fondo Social Europeo” and “Juan de la Cierva” of the Spanish Ministry of Economy and Competitiveness, respectively. Technical and human support provided by Marta Silva is gratefully acknowledged.