has role protective antigen role protective antigen Theileria annulata protein Spag-1 Oliver He Allen Xiang protein Protegen ID: 602; NCBI Protein GI: 161885; NCBITaxon: 5874 The trial vaccination of cattle against T. annulata using recombinant sporozoite antigens (SPAG-1 and p67) and/or merozoite antigens (TAMS 1-1 and 1-2). The aim of these trials was to try and enhance the levels of protection induced compared with previous trials. Different approaches were tried. SPAG-1 was expressed as a fusion protein with a His6 tag and then either incorporated into ISCOMs, with or without TAMS 1-1 and 1-2, or administered with RWL, a proprietary saponin-based adjuvant. Cross-protection studies were also performed by immunizing cattle with the T. parva sporozoite antigen, p67, and then challenging with a T. annulata sporozoite stabilate.All the data collected from these two trials indicate that SPAG-1 administered with RWL is better at inducing an effective immune response than SPAG-1 incorporated into ISCOMs, with or without the presence of merozoite antigens [PubMed: 9668470].