Evaluation of recombinant sporozoite antigen SPAG-I as a vaccine candidateagainst Theileria annulata by the use of different delivery systems

The major sporozoite surface antigen of Theileria annulata (SPAG-1) is a ca ndidate for inclusion in a subunit vaccine. In this paper we summarize the results of 4 vaccination experiments using recombinant SPAG-1 expressed in different systems and presented in different adjuvants. The antigen has bee n presented as either a C terminal 108 amino acid peptide (called SR1) expr essed as both beta-galactosidase and hepatitis B core antigen fusions or as a full-length form expressed as a GST fusion with an N terminal His6 tag. We used different adjuvants, namely Freund's, saponin, ISCOMs and a proprie tary adjuvant supplied by SmithKline Beecham, which we call SKBA. The data point to the conclusion that SPAG-1 can elicit partial protection and is th erefore suitable for inclusion in an eventual multicomponent subunit vaccin e.