A Novel Multi-Antigen Virally Vectored Vaccine against Mycobacterium avium Subspecies paratuberculosis

Tim J Bull,Sarah C Gilbert,Saranya Sridhar,Karim Sidi-Boumedine,Nicola Dierkes,Richard Linedale,John Hermon-Taylor,Niyaz Ahmed

doi:10.1371/journal.pone.0001229

Abstract

Background Mycobacterium avium subspecies paratuberculosis causes systemic infection and chronic intestinal inflammation in many species including primates. Humans are exposed through milk and from sources of environmental contamination. Hitherto, the only vaccines available against Mycobacterium avium subspecies paratuberculosis have been limited to veterinary use and comprised attenuated or killed organisms.MethodsWe developed a vaccine comprising a fusion construct designated HAV, containing components of two secreted and two cell surface Mycobacterium avium subspecies paratuberculosis proteins. HAV was transformed into DNA, human Adenovirus 5 (Ad5) and Modified Vaccinia Ankara (MVA) delivery vectors. Full length expression of the predicted 95 kDa fusion protein was confirmed.Principal FindingsVaccination of naïve and Mycobacterium avium subspecies paratuberculosis infected C57BL/6 mice using DNA-prime/MVA-boost or Ad5-prime/MVA-boost protocols was highly immunogenic resulting in significant IFN-γ ELISPOT responses by splenocytes against recombinant vaccine antigens and a range of HAV specific peptides. This included strong recognition of a T-cell epitope GFAEINPIA located near the C-terminus of the fusion protein. Antibody responses to recombinant vaccine antigens and HAV specific peptides but not GFAEINPIA, also occurred. No immune recognition of vaccine antigens occurred in any sham vaccinated Mycobacterium avium subspecies paratuberculosis infected mice. Vaccination using either protocol significantly attenuated pre-existing Mycobacterium avium subspecies paratuberculosis infection measured by qPCR in spleen and liver and the Ad5-prime/MVA-boost protocol also conferred some protection against subsequent challenge. No adverse effects of vaccination occurred in any of the mice. Conclusions/SignificanceA range of modern veterinary and clinical vaccines for the treatment and prevention of disease caused by Mycobacterium avium subspecies paratuberculosis are needed. The present vaccine proved to be highly immunogenic without adverse effect in mice and both attenuated pre-existing Mycobacterium avium subspecies paratuberculosis infection and conferred protection against subsequent challenge. Further studies of the present vaccine in naturally infected animals and humans are indicated.

Highlights

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative organism of Johne’s disease which can affect many animal species including primates [1]
We describe the safety and immunogenicity of vaccination of C57BL/6 mice using DNAprime/Modified Vaccinia Ankara (MVA)-boost and Adenovirus 5 (Ad5)- prime/MVA-boost and the efficacy of vaccination in therapeutic and prophylactic roles against experimental MAP infection
The assembly and insertion of the fusion construct HAV into DNA vaccine using the pSG2 vector and into the recombinant Ad5 and MVA viral vaccines is described in Materials in Methods

Summary

Introduction

Mycobacterium avium subspecies paratuberculosis (MAP) is the causative organism of Johne’s disease which can affect many animal species including primates [1]. Vaccination of naıve and Mycobacterium avium subspecies paratuberculosis infected C57BL/6 mice using DNA-prime/MVA-boost or Ad5prime/MVA-boost protocols was highly immunogenic resulting in significant IFN-c ELISPOT responses by splenocytes against recombinant vaccine antigens and a range of HAV specific peptides. This included strong recognition of a T-cell epitope GFAEINPIA located near the C-terminus of the fusion protein. The present vaccine proved to be highly immunogenic without adverse effect in mice and both attenuated pre-existing Mycobacterium avium subspecies paratuberculosis infection and conferred protection against subsequent challenge. Further studies of the present vaccine in naturally infected animals and humans are indicated

Methods

Results

Conclusion