Safety and Immunogenicity of Adenovirus and Poxvirus Vectored Vaccines against a Mycobacterium Avium Complex...

Area of Science:

• Vaccinology
• Immunology
• Infectious Diseases

Background:

• Heterologous prime-boost vaccination strategies enhance immune responses in viral vectored vaccines.
• Mycobacterium avium subspecies paratuberculosis (MAP) causes Johne's disease in ruminants, posing economic challenges to the livestock industry.

Purpose of the Study:

• To evaluate the safety and immunogenicity of a Modified Vaccinia Ankara (MVA) vectored vaccine expressing four MAP antigens.
• To assess the vaccine's efficacy as a single dose or as a booster following a simian adenovirus (ChAdOx2) prime.

Main Methods:

• The study involved administering a poxvirus MVA vectored vaccine, either alone or after a ChAdOx2 prime.
• Safety and T-cell immune responses were monitored in the vaccinated subjects.

Main Results:

• The heterologous prime-boost schedule using ChAdOx2 followed by MVA was well tolerated.
• This prime-boost approach successfully induced significant T-cell immune responses.

Conclusions:

• A heterologous prime-boost vaccination strategy with ChAdOx2 and MVA is safe and effective in eliciting T-cell immunity.
• This approach holds promise for developing vaccines against Mycobacterium avium subspecies paratuberculosis.