title: Prime-boost immunisation against tropical theileriosis with two parasite surface antigens: evidence for protection and antigen synergy.
abstract: Current methods for control of tropical theileriosis in cattle suffer from several disadvantages that could be circumvented by development of an effective sub-unit vaccine. Previous work has utilised two major surface antigens (SPAG-1 and Tams1) and conventional adjuvants to provide partial protection against parasite challenge. In this study we have delivered these antigens using the prime-boost system and analysed whether a combination regime can enhance protection against lethal challenge. Delivery of the boost as recombinant protein or expressed from a recombinant MVA vector was also assessed. The results confirmed that immunisation with Tams1 alone could reduce the severity of several disease parameters compared to non-immunised controls and these effects were more marked when recombinant protein was used for boosting compared to MVA delivery. A similar outcome was obtained by immunisation with SPAG-1 alone. Significantly, delivery of SPAG-1 and Tams1 as a cocktail showed enhanced protection. This was manifest by significant improvement in a large range of clinical and parasitological parameters and, most dramatically, by the survival and recovery of 50% of the immunised animals compared to 0% of the controls. Analysis of the antibody response post-challenge showed that while there was a strong response to Tams1, no response to SPAG-1 was detected. In contrast, lymphoproliferation assays showed a significant enhancement of response at day 7 post-challenge in calves of the SPAG-1 group but a dramatic decrease of the proliferation activity in all three groups receiving Tams1. We conclude that immunisation with a cocktail of SPAG-1 and Tams1 generates a synergistic protective response that significantly improves the efficacy of recombinant vaccination against tropical theileriosis. Potential effector mechanisms that could mediate this response are discussed.
authors.affiliation: Laboratoire de Parasitologie, Ecole Nationale de Médecine Vétérinaire de Sidi Thabet, 2020 Sidi Thabet, Tunisia.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Gharbi
authors.forename: Mohamed Aziz
authors.initials: MA
authors.lastname: Darghouth
authors.forename: William
authors.initials: W
authors.lastname: Weir
authors.forename: Frank
authors.initials: F
authors.lastname: Katzer
authors.forename: Nicky
authors.initials: N
authors.lastname: Boulter
authors.forename: Rachel
authors.initials: R
authors.lastname: Adamson
authors.forename: Sarah C
authors.initials: SC
authors.lastname: Gilbert
authors.forename: Frans
authors.initials: F
authors.lastname: Jongejan
authors.forename: Irene
authors.initials: I
authors.lastname: Westbroek
authors.forename: Roger
authors.initials: R
authors.lastname: Hall
authors.forename: Andrew
authors.initials: A
authors.lastname: Tait
authors.forename: Brian
authors.initials: B
authors.lastname: Shiels
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D000953:Antigens, Protozoan / Q000276:immunology*; D000954:Antigens, Surface / Q000276:immunology; D002417:Cattle; D002418:Cattle Diseases / Q000517:prevention & control*; D049109:Cell Proliferation; D007117:Immunization, Secondary / Q000379:methods*; D007963:Leukocytes, Mononuclear / Q000276:immunology; D016052:Protozoan Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D016019:Survival Analysis; D016794:Theileria / Q000276:immunology*; D013801:Theileriasis / Q000517:prevention & control*; D014611:Vaccination / Q000379:methods*; D022223:Vaccines, Subunit / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology; D014616:Vaccinia virus
chemical_list: D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D000954:Antigens, Surface; D016052:Protozoan Vaccines; D022223:Vaccines, Subunit