Failure of a recombinant Babesia bovis antigen to protect cattle against heterologous strain challenge.
Groups of cattle were inoculated subcutaneously with (i) a recombinant DNA-derived Babesia bovis protein (KaBbl-GZ) fused to beta-galactosidase and combined with adjuvants, or (ii) native beta-galactosidase (GZ) plus adjuvant, or (iii) adjuvant only or (iv) a live, attenuated B bovis vaccine. KaBbl-GZ was produced in the lambda gt11-amp3 system as a 5-10 kD babesial polypeptide linked to GZ. KaBbl has previously been shown to be an immunodominant antigen of B bovis, localised at the apex of the parasite, and present in a range of B bovis strains. High levels of GZ antibodies were observed in KaBbl-GZ and GZ inoculated cattle, but specific KaBbl antibodies could not be detected by ELISA. Five months after primary inoculation, all cattle were blood challenged with a virulent heterologous B bovis strain. Despite four inoculations with KaBbl-GZ, significant protection against the challenge was not observed.
Timms
P
P
Animal Research Institute, Queensland Department of Primary Industries, Australia.
Barry
D N
DN
Gill
A C
AC
Sharp
P J
PJ
de Vos
A J
AJ
D000818:Animals; D000953:Antigens, Protozoan / Q000008:administration & dosage*; D001403:Babesia / Q000276:immunology*; D001404:Babesiosis / Q000517:prevention & control*; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control*; D007279:Injections, Subcutaneous; D011994:Recombinant Proteins
D000953:Antigens, Protozoan; D011994:Recombinant Proteins