title: Pulmonary tuberculosis in Asian elephants (Elephas maximus): histologic lesions with correlation to local immune responses.
abstract: Although Mycobacterium tuberculosis infection is an important health concern for Asian elephants (Elephas maximus), no studies have evaluated the associated local immune responses or histologic lesions. In primates including humans, latent tuberculosis is distinguished by well-organized granulomas with TH1 cytokine expression, whereas active disease is characterized by poorly organized inflammation and local imbalance in TH1/TH2 cytokines. This study examined archival, formalin-fixed, paraffin-embedded lung samples from 5 tuberculosis-negative and 9 tuberculosis-positive Asian elephants. Lesions were assessed by light microscopy, and lymphoid infiltrates were characterized by CD3 and CD20 immunolabeling. Expression of TH1 (interferon [IFN]-γ, tumor necrosis factor [TNF]-α) and TH2 (interleukin [IL]-4, IL-10, transforming growth factor [TGF]-β) cytokines was determined using in situ hybridization. In 6 of 9 samples, inflammation was similar to the pattern of primate active disease with low to moderate numbers of lymphocytes, most of which were CD20 positive. In 1 sample, inflammation was most similar to latent tuberculosis in primates with numerous CD3-positive lymphocytes. Expression of IFN-γ was detected in 3 of 8 tuberculosis-positive samples. Expression of TNF-α was detected in 3 of 8 positive samples, including the one with latent morphology. Low-level expression of IL-4 was present in 4 of 8 positive samples. Only single positive samples displayed expression of IL-10 and TGF-β. Tuberculosis-negative samples generally lacked cytokine expression. Results showed heterogeneity in lesions of elephant tuberculosis similar to those of latent and active disease in primates, with variable expression of both TH1 and TH2 cytokines.
authors.affiliation: University of Illinois Zoological Pathology Program, Loyola University Medical Center, Maywood, IL, USA landolfi@illinois.edu.
authors.forename: J A
authors.initials: JA
authors.lastname: Landolfi
authors.affiliation: University of Illinois Zoological Pathology Program, Loyola University Medical Center, Maywood, IL, USA.
authors.forename: K A
authors.initials: KA
authors.lastname: Terio
authors.affiliation: DST/MRC Centre of Excellence for Biomedical Tuberculosis Research, Division of Molecular Biology and Human Genetics, Stellenbosch University, Tygerberg, South Africa.
authors.forename: M
authors.initials: M
authors.lastname: Miller
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: B F
authors.initials: BF
authors.lastname: Junecko
authors.affiliation: Department of Infectious Diseases and Microbiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, USA.
authors.forename: T
authors.initials: T
authors.lastname: Reinhart
mesh_terms: D000818:Animals; D004606:Elephants / Q000276:immunology / Q000382:microbiology*; D017403:In Situ Hybridization / Q000662:veterinary; D007371:Interferon-gamma / Q000378:metabolism; D008168:Lung / Q000473:pathology; D014397:Tuberculosis, Pulmonary / Q000276:immunology / Q000473:pathology / Q000662:veterinary*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D014409:Tumor Necrosis Factor-alpha; D007371:Interferon-gamma
keywords: Elephas maximus; cytokine; elephant; local immunity; tuberculosis