This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Fukumoto, S. Articles by Suzuki, H. Search for Related Content PubMed PubMed Citation Articles by Fukumoto, S. Articles by Suzuki, H.

 Previous Article  |  Next Article 

Clinical and Diagnostic Laboratory Immunology, July 2003, p. 596-601, Vol. 10, No. 4
1071-412X/03/$08.00+0     DOI: 10.1128/CDLI.10.4.596-601.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

High-Level Expression of Truncated Surface Antigen P50 of Babesia gibsoni in Insect Cells by Baculovirus and Evaluation of Its Immunogenicity and Antigenicity

Shinya Fukumoto,¹ Xuenan Xuan,¹ Kimie Kadota,¹ Ikuo Igarashi,¹ Chihiro Sugimoto,¹ Kozo Fujisaki,¹ Hideyuki Nagasawa,¹ Takeshi Mikami,² and Hiroshi Suzuki^1*

National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Obihiro, Hokkaido 080-8555,¹ Laboratory of Veterinary Public Health, College of Bioresource Science, Nihon University, Fujisawa, Kanagawa 252-8510, Japan²

Received 9 January 2003/ Returned for modification 25 February 2003/ Accepted 20 March 2003

Previously, we identified an immunodominant antigen, P50 of Babesia gibsoni. In the present study, the gene encoding the truncated P50 (rP50t) without a C-terminal hydrophobic region (29 amino acids [aa]) was expressed in insect cells by a recombinant baculovirus. The highly hydrophobic C-terminal 20-aa regions seems to be a transmembrane region, which was evidenced by the fact that rP50t was effectively secreted into the supernatant of insect cells infected with the recombinant baculovirus. N-terminal amino acid sequence analysis of rP50t indicated that N-terminal 19 aa function as a signal peptide. The expression level of rP50t reached up to 2 mg per 10⁸ cells infected with the recombinant baculovirus. The immunogenic property of rP50t was evaluated by an immunization test in mice. Mice immunized with rP50t induced a high-level antibody titer against the B. gibsoni merozoite. Monoclonal antibodies (MAbs) to rP50t were produced in mice to determine the immunogenic regions of P50. The epitope(s) recognized by all five MAbs were located between aa 190 and 273, suggesting that the central part of P50 is a highly immunogenic region. The diagnostic potential of rP50t was evaluated using an enzyme-linked immunosorbent assay (ELISA). The ELISA was able to differentiate clearly (P < 0.0001) between B. gibsoni-infected dog serum and B. canis-infected dog serum or noninfected dog serum. Our results indicated that the rP50t may provide a useful potential immunogenic reagent for use in diagnosis and as a subunit vaccine to control B. gibsoni infection in dogs.

---

* Corresponding author. Mailing address: National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada-cho, Obihiro, Hokkaido 080-8555, Japan. Phone: 81-155-49-5640. Fax: 81-155-49-5643. E-mail: hisuzuki{at}obihiro.ac.jp.

---

Clinical and Diagnostic Laboratory Immunology, July 2003, p. 596-601, Vol. 10, No. 4
1071-412X/03/$08.00+0     DOI: 10.1128/CDLI.10.4.596-601.2003
Copyright © 2003, American Society for Microbiology. All Rights Reserved.

This article has been cited by other articles:

• Fukumoto, S., Tamaki, Y., Shirafuji, H., Harakawa, S., Suzuki, H., Xuan, X. (2005). Immunization with Recombinant Surface Antigen P50 of Babesia gibsoni Expressed in Insect Cells Induced Parasite Growth Inhibition in Dogs. CVI 12: 557-559 [Abstract] [Full Text]  
• Fukumoto, S., Xuan, X., Takabatake, N., Igarashi, I., Sugimoto, C., Fujisaki, K., Nagasawa, H., Mikami, T., Suzuki, H. (2004). Inhibitory Effect of Antiserum to Surface Antigen P50 of Babesia gibsoni on Growth of Parasites in Severe Combined Immunodeficiency Mice Given Canine Red Blood Cells. Infect. Immun. 72: 1795-1798 [Abstract] [Full Text]