title: Evaluation of protection in a mouse model after vaccination with Mycobacterium avium subsp. paratuberculois protein cocktails.
abstract: Whole-cell vaccines successfully reduce signs of clinical disease and fecal shedding of Mycobacterium avium subsp. paratuberculosis (MAP), however, these vaccines have some limitations. The present study was conducted to identify MAP proteins that might be candidates for the development of an improved vaccine. MAP proteins were screened for immunogenicity in naturally infected cattle and selected based upon reactivity in the interferon-γ (IFN-γ) and Western blot assays. Proteins (MAP1087, MAP1204, MAP1272c, and MAP2077c) were arrayed into 4 overlapping cocktails containing 3 proteins each. The efficacy of the proteins within these cocktails as vaccine candidates was evaluated by subcutaneous immunization of mice, followed by challenge with live, virulent MAP. All MAP protein cocktails significantly reduced the recovery of live MAP from the ileum, while cocktails 1 and 3 reduced colonization in the liver. No significant differences were seen in the mesenteric lymph node or spleen, however, cocktail 1 reduced viable MAP in the mesenteric lymph node compared to other treatments. Stimulation of splenocytes upregulated antigen-specific IFN-γ and IL-23 secretion in all treatment groups, regardless of vaccination. Interestingly, IL-4 was moderately downregulated for vaccinates compared to control infected mice. An increase in total CD25 expression was noted for 3 of the 4 vaccinate groups upon stimulation of splenocytes with a whole cell sonicate of MAP, with this effect becoming more significant within CD4CD25+ and CD8CD25+ subpopulations. The present study demonstrated that MAP proteins are useful as vaccine candidates to reduce MAP tissue burden.
authors.affiliation: USDA-ARS, National Animal Disease Center, Ames, IA 50010, USA. judy.stabel@ars.usda.gov
authors.forename: J R
authors.initials: JR
authors.lastname: Stabel
authors.forename: A
authors.initials: A
authors.lastname: Barnhill
authors.forename: J P
authors.initials: JP
authors.lastname: Bannantine
authors.forename: Y F
authors.initials: YF
authors.lastname: Chang
authors.forename: M A
authors.initials: MA
authors.lastname: Osman
mesh_terms: D000818:Animals; D001426:Bacterial Proteins / Q000276:immunology*; D007371:Interferon-gamma / Q000378:metabolism; D053759:Interleukin-23 / Q000378:metabolism; D015847:Interleukin-4 / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009162:Mycobacterium avium / Q000276:immunology* / Q000472:pathogenicity*; D014376:Tuberculosis / Q000276:immunology / Q000517:prevention & control*; D014611:Vaccination / Q000379:methods*
chemical_list: D001426:Bacterial Proteins; D053759:Interleukin-23; D015847:Interleukin-4; D007371:Interferon-gamma