RT info:eu-repo/semantics/article T1 Immunohistochemical characterization of tuberculous lesions in sheep naturally infected with Mycobacterium bovis A1 Vallejo, Raquel A1 García Marín, Juan Francisco A1 Juste, Ramón Antonio A1 Muñoz Mendoza, Marta A1 Salguero, Francisco Javier A1 Balseiro Morales, Ana María A2 Sanidad Animal K1 Veterinaria K1 Tuberculosis K1 Sheep K1 Immunohistochemistry K1 Mycobacterium bovis K1 Granuloma K1 3109 Ciencias Veterinarias AB [EN] Background: Sheep have been traditionally considered as less susceptible to Mycobacterium bovis (Mbovis) infection than other domestic ruminants such as cattle and goats. However, there is increasing evidence for the role of this species as a domestic Mbovis reservoir, mostly when sheep share grazing fields with infected cattle and goats. Nevertheless, there is a lack of information about the pathogenesis and the immune response of Mbovis infection in sheep. The goals of this study were to characterize the granuloma stages produced by the natural infection of Mbovis in sheep, to compare them with other species and to identify possible differences in the sheep immune response. Samples from bronchial lymph nodes from twelve Mbovis-naturally infected sheep were used. Four immunohistochemical protocols for the specific detection of T-lymphocytes, B-lymphocytes, plasma cells and macrophages were performed to study the local immune reaction within the granulomas. Results: Differences were observed in the predominant cell type present in each type of granuloma, as well as differences and similarities with the development of tuberculous granulomas in other species. Very low numbers of T-lymphocytes were observed in all granuloma types indicating that specific cellular immune response mediated by T-cells might not be of much importance in sheep in the early stages of infection, when macrophages are the predominant cell type within lesions. Plasma cells and mainly B lymphocytes increased considerably as the granuloma developed being attracted to the lesions in a shift towards a Th2 response against the increasing amounts of mycobacteria. Therefore, we have proposed that the granulomas could be defined as initial, developed and terminal. Conclusions: Results showed that the study of the lymphoid tissue granulomata reinforces the view that the three different types of granuloma represent stages of lesion progression and suggest an explanation to the higher resistance of sheep based on a higher effective innate immune response to control tuberculosis infection. PB BMC LK https://hdl.handle.net/10612/19553 UL https://hdl.handle.net/10612/19553 NO Vallejo, R., García Marín, J. F., Juste, R. A., Muñoz-Mendoza, M., Salguero, F. J., & Balseiro, A. (2018). Immunohistochemical characterization of tuberculous lesions in sheep naturally infected with Mycobacterium bovis. BMC Veterinary Research, 14(1). https://doi.org/10.1186/S12917-018-1476-2 NO © The Author(s). 2018 Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. DS BULERIA. Repositorio Institucional de la Universidad de León RD 21-jun-2024