title: ZAP-70, CTLA-4 and proximal T cell receptor signaling in cows infected with Mycobacterium avium subsp. paratuberculosis.
abstract: Paratuberculosis is a chronic intestinal disease of ruminant animals caused by Mycobacterium avium subsp. paratuberculosis (MAP). A hallmark of paratuberculosis is a transition from a cell-mediated Th1 type response to a humoral Th2 response with the progression of disease from a subclinical to clinical state. The objective of this study was to investigate the expression of two crucial molecules in T cell function, ZAP-70 (zeta-chain-associated protein of 70 kDa) and CTLA-4 (cytotoxic T-lymphocyte antigen-4), in cows naturally infected with MAP. Peripheral blood mononuclear cells (PBMCs) isolated from control non-infected cows (n=5), and cows in subclinical (n=6) and clinical stages of paratuberculosis (n=6) were cultured alone (medium only), and with concanavalin A, and a whole cell sonicate of MAP for 24, 72 and 144 h to measure the dynamic changes of ZAP-70 and CTLA-4 expression on CD4, CD8, and gamma delta (γδ) T cells. Flow cytometry was also performed to measure ZAP-70 phosphorylation to examine proximal T cell receptor signaling in animals of different disease status. The surface expression of CTLA-4 was increased in animals in subclinical stage of infection while levels of ZAP-70 were decreased in CD4+ T cells of both subclinical and clinical animals, indicating a change in T cell phenotype with disease state. Interestingly, proximal T cell receptor signaling was not altered in infected animals. This study demonstrated changes in crucial signaling molecules in animals infected with MAP, thereby elucidating T cell alterations associated with disease progression.
authors.affiliation: Department of Veterinary Microbiology and Preventive Medicine, Iowa State University, Ames, IA 50011, United States.
authors.forename: Fernando L
authors.initials: FL
authors.lastname: Leite
authors.affiliation: Federal University of Pelotas, Pelotas, Brazil.
authors.forename: Livia B
authors.initials: LB
authors.lastname: Eslabão
authors.affiliation: USDA-ARS, National Animal Disease Center, Ames, IA 50010, United States.
authors.forename: Bruce
authors.initials: B
authors.lastname: Pesch
authors.affiliation: USDA-ARS, National Animal Disease Center, Ames, IA 50010, United States.
authors.forename: John P
authors.initials: JP
authors.lastname: Bannantine
authors.affiliation: USDA-ARS, National Animal Disease Center, Ames, IA 50010, United States.
authors.forename: Timothy A
authors.initials: TA
authors.lastname: Reinhardt
authors.affiliation: USDA-ARS, National Animal Disease Center, Ames, IA 50010, United States. Electronic address: judy.stabel@ars.usda.gov.
authors.forename: Judith R
authors.initials: JR
authors.lastname: Stabel
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism; D060908:CTLA-4 Antigen / Q000378:metabolism*; D002417:Cattle; D002418:Cattle Diseases / Q000276:immunology*; D005260:Female; D007082:Ileum / Q000276:immunology; D007371:Interferon-gamma / Q000378:metabolism; D016927:Mycobacterium avium subsp. paratuberculosis / Q000276:immunology / Q000472:pathogenicity; D010283:Paratuberculosis / Q000276:immunology*; D010766:Phosphorylation; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism*; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000276:immunology* / Q000378:metabolism
chemical_list: D060908:CTLA-4 Antigen; D011948:Receptors, Antigen, T-Cell; D007371:Interferon-gamma; D051746:ZAP-70 Protein-Tyrosine Kinase
keywords: CTLA-4; Mycobacterium avium subsp. paratuberculosis; T cell function; ZAP-70