Roadmap for the development of diagnostic test for bTB

What are we trying to achieve and why? What is the problem we are trying to solve?

To identify which M. bovis antigens would be most suitable for inclusion in tests based on humoral and/or CMI responses.

What are the scientific and technological challenges
(knowledge gaps needing to be addressed)?

The host may be responding to different M. bovis antigens at different stages of infections.
M. bovis may be expressing different antigens at different stages, i.e., exposure, infection, reactivation, latency etc.
Antigens comprise peptides and proteins, including post translational modifications such as glycosylation and acylation.

What approaches could/should be taken to address the research question?

• Antigen mining based on pathogen genome sequence – Identification of T-cell antigens and epitopes using available bioinformatics algorithms and machine learning.
• Comparative genomics of M bovis and other mycobacteria to identify markers for new diagnostics.
• Identification of different antigens that are expressed by the pathogen during infection.
• Immunoblotting using sera from infected animals.
• Gene sequences being expressed in vivo at different stages of infection.
• Most focus has understandably been on proteins and peptides; lipids and modified proteins likely to be important in host pathogen interactions and TB lifecycle.
• 10% of the M. bovis genome comprises PE and PPE proteins; their role not clear.

What else needs to be done before we can solve this need?

HPI – Identification of which pathogen genes are being expressed in different stages of infection

Existing knowledge including successes and failures