Evaluation of immune responses and protective efficacy in a goat model following immunization with a coctail of recombinant antigens and a polyprotein of Mycobacterium avium subsp. paratuberculosis
Animal Health Diagnostic Center, Department of Population Medicine and Diagnostic Sciences, College of Veterinary Medicine, Cornell University, UpTwoer Road, Ithaca, NY 14853, USA. Vaccine
(Impact Factor: 3.62).
11/2008; 27(1):123-35. DOI: 10.1016/j.vaccine.2008.10.019
The protective efficacy of four recombinant antigens (85A, 85B, superoxide dismutase [SOD], and a fusion polypeptide [Map74F]) of Mycobacterium avium subsp. paratuberculosis (MAP) along with the adjuvant dimethydioctadecyl ammonium bromide (DDA) was assessed in a goat challenge model. Animals were immunized with the four antigens with adjuvant DDA (Group I, eight goat kids) or without the adjuvant (Group II, eight goat kids) or adjuvant only (Group III, nine goat kids). Animals were boostered 3 weeks after the primary vaccination and challenged 3 weeks after the booster. Significant antigen-specific lymphoproliferation was observed in the immunized animals 3 weeks after the booster immunization. This response increased further at 4 weeks after the booster. Similarly, antigen-specific IFN-gamma responses increased in the immunized animals 3 weeks after the booster. The response was significantly higher for 85A and Map74F at 10 weeks after primary vaccination (APV) in Group I animals compared to the other two groups. CD4+ T-cell populations were higher in the vaccinated animals from 6 to 10 weeks APV than those of the control animals. A significant increase in recombinant antigen-specific IFN-gamma gene expression was detected in the vaccinated animals. At necropsy (38 weeks APV), our multicomponent subunit vaccine imparted a significant protection in terms of reduction of MAP burden in target organs as compared to sham-immunized goats. This study indicates that our multicomponent subunit vaccine induced a good Th1 response and conferred protection against MAP infection in a goat challenge model.
Available from: Judith R. Stabel
- "Subunit vaccines against MAP are likely to obviate some of the shortcomings of whole-cell vaccines, such as severe inflammation and granuloma formation at the injection site. However, subunit vaccines that have been tested thus far have yielded incomplete protection results in murine models of infection (Koets et al., 2006; Stabel et al., 2012) and even when combinations of proteins are used in calves and goats (Koets et al., 2006; Kathaperumal et al., 2008, 2009). For example, MAP was colonized in the lymph node and spleen at similar levels in control and vaccinate mice using a protein cocktail (Stabel et al., 2012). "
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ABSTRACT: Since the early 1980s, several investigations have focused on developing a vaccine against Mycobacterium avium subspecies paratuberculosis (MAP), the causative agent of Johne's disease in cattle and sheep. These studies used whole-cell inactivated vaccines that have proven useful in limiting disease progression, but have not prevented infection. In contrast, modified live vaccines that invoke a Th1 type immune response, may improve protection against infection. Spurred by recent advances in the ability to create defined knockouts in MAP, several independent laboratories have developed modified live vaccine candidates by transpositional mutation of virulence and metabolic genes in MAP. In order to accelerate the process of identification and comparative evaluation of the most promising modified live MAP vaccine candidates, members of a multi-institutional USDA-funded research consortium, the Johne's disease integrated program (JDIP), met to establish a standardized testing platform using agreed upon protocols. A total of 22 candidates vaccine strains developed in five independent laboratories in the United States and New Zealand voluntarily entered into a double blind stage gated trial pipeline. In Phase I, the survival characteristics of each candidate were determined in bovine macrophages. Attenuated strains moved to Phase II, where tissue colonization of C57/BL6 mice were evaluated in a challenge model. In Phase III, five promising candidates from Phase I and II were evaluated for their ability to reduce fecal shedding, tissue colonization and pathology in a baby goat challenge model. Formation of a multi-institutional consortium for vaccine strain evaluation has revealed insights for the implementation of vaccine trials for Johne's disease and other animal pathogens. We conclude by suggesting the best way forward based on this 3-phase trial experience and challenge the rationale for use of a macrophage-to-mouse-to native host pipeline for MAP vaccine development.
Available from: Shyamala Thirunavukkarasu
- "Early diagnosis of MAP-infection using serodiagnostic assays is hindered by the fact that affected animals can take a long time, often years, to develop detectable serum antibody responses using existing antigens (Köhler et al., 2008; McKenna et al., 2005; Nielsen and Toft, 2008). Other approaches for early diagnosis include the identification of MAP-specific antigens that detect cell mediated immune (CMI) responses such as the secretion of antigen-specific IFNc or lymphocyte proliferation elicited early after exposure to mycobacteria (de Silva et al., 2010, 2011; Kathaperumal et al., 2009; Kurade and Tripathi, 2008; Malamo et al., 2006; Nagata et al., 2009; Shin et al., 2005). A good diagnostic antigen is one that is able to be recognised by the immune cells and antibodies of MAP-affected animals even in subclinical stages of infection (Mikkelsen et al., 2011). "
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ABSTRACT: Paratuberculosis caused by Mycobacterium avium subsp. paratuberculosis (MAP) is a chronic infectious disease affecting domestic and wild ruminants. Antigens currently used for the diagnosis of paratuberculosis are whole-cell derived crude preparations. The identification of MAP-specific antigens for the specific and early diagnosis of this infection is strongly needed. This study assessed the ability of the MAP-specific synthetic lipopeptide antigen Para-LP-01 to invoke specific serum antibody (Ab) and cell-mediated immune (CMI) responses in sheep experimentally exposed to MAP S strain. Responses were compared to those elicited by the crude whole-cell derived MAP 316v antigen (316v). Para-LP-01 induced a significant serum Ab response in MAP-infected sheep in comparison with unexposed or uninfected sheep, but failed to induce detectable CMI responses including production of IFN-γ, IL-10 and lymphoproliferation, unlike 316v which invoked both CMI and serum Ab responses in MAP-exposed sheep. Para-LP-01 is a suitable antigen for serodiagnosis of MAP-infection in sheep. The differential induction of humoral and CMI responses by lipid based antigens could enhance current understanding of the role played by cell-wall associated lipid antigens in the pathogenesis of MAP-infection.
Available from: Rebecca Lee Smith
- "As there is no perfect vaccine, MAP vaccination was modeled as vaccination of calves with an imperfect vaccine ('leaky') that partially reduces the susceptibility of the host and has a 'failure in take' effect (Woolhouse et al., 1997; Halloran et al., 2010). In this study we assumed the use of novel MAP vaccines that were able to partially prevent infection, such as recombinant vaccines that prevent MAP from attaching to the intestinal surface (Kathaperumal et al., 2009), rather than heat-killed whole cell-based vaccines that have not been effective in preventing susceptible calves being infected (Whitlock, 2010; Alonso-Hearn et al., 2012). "
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ABSTRACT: Paratuberculosis, or Johne's disease (JD), is a chronic enteric disease of ruminants infected by Mycobacterium avium subsp. paratuberculosis (MAP) that causes a significant financial loss in dairy industry. To reduce prevalence and transmission in dairy herds infected with MAP, control programs have been implemented, including test-based culling, improved calf rearing management, and vaccination. The important issue of preventing MAP invasion into a MAP-free herd has been less investigated, however. The objective of this study was to examine whether vaccination was able to prevent MAP invasion in dairy cattle using a stochastic simulation approach. We developed a MAP vaccination model in which calves were vaccinated with a vaccine that is both imperfect in reducing the susceptibility of the host ('leaky') and that does not successfully immunize all calves ('failure in take'). Probability of MAP persistence and the number of infected animals in herds were computed for both control and vaccinated herds over a ten-year period after introduction of an initial infected heifer. Global parameter sensitivity analyses were performed to find the most influential parameters for MAP invasion. Our results show that vaccination of calves is effective in preventing MAP invasion, provided that the vaccine is of high efficacy in both reduction of susceptibility and 'take' effects; however, there is still a small chance (<0.15) that MAP can be sustained in herds over a long time (>10 years) due to vertical transmission. This study indicates that reduction in the transmission rate of high shedders (>50 CFU), the number of infected heifers initially introduced to herds, and vertical transmission are important to further decrease the probability of MAP becoming endemic and the overall number of infected animals in endemic herds. The simulation work is useful for designing vaccination programs aimed at preventing MAP invasion in MAP-free herds.
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