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The protection afforded to cattle immunized with Theileria annulata infected cell line is enhanced by subunit vaccine candidate Ta SP
Author(s) -
Saaid Abubakar A.,
Salih Diaeldin A.,
Elhaj Limia M.,
Abdalla Mohammed A.,
Baumann Maximilian,
Obara Isaiah,
Ahmed Jabbar S.,
Clausen PeterHenning,
El Hussein Abdel Rahim M.
Publication year - 2020
Publication title -
transboundary and emerging diseases
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.392
H-Index - 63
eISSN - 1865-1682
pISSN - 1865-1674
DOI - 10.1111/tbed.13374
Subject(s) - vaccination , adjuvant , virology , immunization , biology , tick infestation , inactivated vaccine , attenuated vaccine , recombinant dna , veterinary medicine , immunology , medicine , immune system , tick , biochemistry , virulence , gene
Tropical theileriosis constraints the development of the dairy industry in the Sudan and vaccination using live attenuated schizont vaccines is considered a promising measure for its control. The present study was carried out to investigate the ability of recombinant T. annulata surface protein ( Ta SP) to improve the efficacy of the attenuated Atbara cell line in protecting calves against field challenge. To this end, 23 cross‐bred (Friesian × Kenana) calves were divided into four groups. Animals in group 1 ( n = 5) were left unvaccinated. Group 2 ( n = 6) received the Atbara cell line, animals in group 3 ( n = 6) were immunized with three doses of Ta SP on days 21, 49 and 77, while animals in group 4 ( n = 6) received the cell line vaccine on day 0 and three doses of Ta SP in Freund's incomplete adjuvant at days 21, 49 and 77. Twenty‐eight days after the last Ta SP boost, all groups were challenged by exposing them to natural field tick infestation in a region known to be endemic for tropical theileriosis. No thermal reactions, piroplasms or schizonts were observed in the immunized animals following immunization. Upon challenge, all animals showed a range of symptoms of clinical theileriosis with variable degrees of severity. The application of Ta SP alone appeared to have no effect in terms of protection. The efficacy of the cell line alone was lower than the 100% level of protection against mortality observed in the group that received the combined cell line vaccine and Ta SP, suggesting a synergistic effect of this combination.