Previous research in our lab has shown that intramuscular immunization of cattle with activation-associated secreted proteins (ASP), purified from excretory-secretory material of adult Ostertagia ostertagi and Cooperia oncophora worms, in combination with the QuilA adjuvant induces significant levels of protection against a homologous challenge infection with these gastrointestinal nematodes. Vaccines based on recombinant ASP proteins, however, failed to induce similar levels of protection. In PARAGONE, the protein structure and secondary modifications of protective native ASP proteins and non-protective recombinant ASP are compared (dr. Jimmy Borloo) to discover structural epitopes that are associated with a protective immune response. Mucosal immune responses in calves vaccinated with the protective vaccine and with unprotective recombinant vaccines are compared, to identify immune mechanisms asscociated with protection. A mice model and in vitro assays are developed to screen recombinant vaccine candidates (prof. Peter Geldhof). Together, these results should lead to improved recombinant antigen production and antigen delivery. Finally, vaccine studies will be performed to test the protective capacity of the C. oncophora ASP vaccine against related Cooperia species in sheep and cattle and to evaluate a multivalent Ostertagia-Cooperia vaccine in field conditions in cattle (prof. Edwin Claerebout). In addition, in collaboration with the Moredun Research Institute, a prototype vaccine that protects sheep against the scab mite Psoroptes ovis will be tested in Belgian Blue cattle, which are notoriously susceptible to this ectoparasite. In the PARAGONE management structure, Prof. Claerebout is work package leader for WP1 (vaccine trials).