Spherical body protein 4 is a new serological antigen for global detection of Babesia bovis infection in cattle.
Five Babesia bovis recombinant proteins, including merozoite surface antigen 2c (BbMSA-2c), C-terminal rhoptry-associated protein 1 (BbRAP-1/CT), truncated thrombospondin-related anonymous protein (BbTRAP-T), spherical body protein 1 (BbSBP-1), and spherical body protein 4 (BbSBP-4), were evaluated as diagnostic antigens to detect the infection in cattle. The recombinant proteins were highly antigenic when tested with experimentally B. bovis-infected bovine serum in Western blot analysis. Furthermore, five antisera that had been raised against each of the recombinant proteins reacted specifically with the corresponding authentic protein, as determined in Western blot analysis. Next, enzyme-linked immunosorbent assays (ELISAs) using these recombinant proteins were evaluated for diagnostic use, and the sensitivity and specificity of each protein were demonstrated with a series of serum samples from experimentally B. bovis-infected cattle. Furthermore, a total of 669 field serum samples collected from cattle in regions of B. bovis endemicity in seven countries were tested with the ELISAs, and the results were compared to those of an indirect fluorescent antibody test (IFAT), as a reference. Among five recombinant antigens, recombinant BbSBP-4 (rBbSBP-4) had the highest concordance rate (85.3%) and kappa value (0.705), indicating its reliability in the detection of specific antibodies to B. bovis in cattle, even in different geographical regions. Overall, we have successfully developed an ELISA based on rBbSBP-4 as a new serological antigen for a practical and sensitive test which will be applicable for epidemiologic survey and control programs in the future.
National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan.
Mohamad Alaa
MA
Terkawi
Nguyen Xuan
NX
Huyen
Putut Eko
PE
Wibowo
Faasoa Junior
FJ
Seuseu
Mahmoud
M
Aboulaila
Akio
A
Ueno
Youn-Kyoung
YK
Goo
Naoaki
N
Yokoyama
Xuenan
X
Xuan
Ikuo
I
Igarashi
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000235:genetics; D016793:Babesia bovis / Q000276:immunology / Q000302:isolation & purification*; D001404:Babesiosis / Q000175:diagnosis / Q000469:parasitology / Q000662:veterinary*; D015153:Blotting, Western; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis* / Q000469:parasitology; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D008969:Molecular Sequence Data; D010274:Parasitology / Q000379:methods*; D015800:Protozoan Proteins / Q000235:genetics; D011994:Recombinant Proteins / Q000235:genetics; D012680:Sensitivity and Specificity; D017422:Sequence Analysis, DNA
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D011994:Recombinant Proteins