Roadmap for development of diagnostic tests for helminths

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

• The production of recombinant parasite antigen for inclusion in diagnostic tests
• Efficient and reliable production of target species- and stage-specific antigens to allow sensitive, specific and quantitative diagnosis.

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

Expression systems are needed that will provide high yields of soluble antigens with appropriate conformation and post-tralational modifications with respect to native antigens.

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

• Expression systems that preserve the conformational structure and post-tranlational modifications of the native antigen
• Expression systems that allow large scale production of parasite antigens
• Expression systems that produce high yields of soluble antigen in a recoverable form.

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

The identification of appropriate antigens for testing in expression systems. This in turn requires good genomic resources (well assembled and annotated genomes) for target helminth species, an understanding of the complexity of relevant gene families, and genetic polymorphisms of antigen genes.

Existing knowledge including successes and failures

• For fluke, several recombinant antigens have been produced and one in particular, a mutant CL1 (lacking the active site) is used widely in diagnostic tests. But not commercially available, not available as a
  penside form for ruminants.
• For nematodes some recombinant (e.g. Teladorsagia, Dictyocaulus) as well as native (ES) antigens (Ostertagia ostertagi) have been successfully employed in different ELISA formats (serum, milk)