Characterization of Neospora caninum surface protein NcSRS2 based on baculovirus expression system and its application for serodiagnosis of Neospora infection

• Published in: Journal of clinical microbiology 2001-11, Vol.39 (11), p.3987-3991
• Main Authors: NISHIKAWA, Yoshifumi, KOUSAKA, Yuko, TRAGOOLPUA, Khajornsak, XUENAN XUAN, MAKALA, Levi, FUJISAKI, Kozo, MIKAMI, Takeshi, NAGASAWA, Hideyuki
• Format: Article
• Language: English
• Subjects: Animal viral diseases; Animals; Antibodies, Monoclonal - immunology; Antibodies, Protozoan - blood; Antibodies, Protozoan - immunology; Antigens, Protozoan - genetics; Antigens, Protozoan - immunology; Antigens, Protozoan - metabolism; Antigens, Surface; Baculovirus; Biological and medical sciences; Blotting, Western; Cattle; Cattle Diseases - diagnosis; Cattle Diseases - parasitology; Cell Line; Clinical Veterinary Microbiology; Coccidiosis - diagnosis; Coccidiosis - parasitology; Coccidiosis - veterinary; Dogs; Enzyme-Linked Immunosorbent Assay; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Humans; Infectious diseases; Medical sciences; Mice; Mice, Inbred BALB C; Microbiology; Molecular immunology; NcSRS2 protein; Neospora - immunology; Neospora caninum; Nucleopolyhedrovirus - genetics; Nucleopolyhedrovirus - metabolism; Protozoan Proteins - genetics; Protozoan Proteins - immunology; Protozoan Proteins - metabolism; Recombinant Proteins - immunology; Recombinant Proteins - metabolism; Sensitivity and Specificity; Spodoptera; Techniques; Viral diseases
• ISSN: 0095-1137; 1098-660X
• DOI: 10.1128/JCM.39.11.3987-3991.2001

The baculovirus expression system has proved to be a useful tool for the production of recombinant proteins. Here we have characterized the Neospora caninum surface protein NcSRS2 produced by two types of the recombinant virus and also have developed an enzyme-linked immunosorbent assay (ELISA) using recombinant NcSRS2 for the serologic diagnosis of Neospora infection. Western blot analysis showed two major protein bands that were detectable in insect cells infected with each recombinant baculovirus, and a lower-molecular-weight protein was detected in culture supernatants from a cell infected with the recombinant virus lacking the hydrophobic C-terminal tail. Analysis of the N-terminal amino acids showed that the secreted NcSRS2 lacked 6 kDa of the N-terminal signal peptide. Moreover, the detergent-soluble protein of insect cells infected with the recombinant baculovirus expressing the full-length NcSRS2 gene was used to develop an ELISA system based on specificity and reactivity to antisera against Toxoplasma gondii, Hammondia heydorni, or N. caninum. Anti-N. caninum mouse, dog, and bovine sera recognized the recombinant NcSRS2 on Western blots. Furthermore, we have shown that the developed ELISA system consistently discriminates indirect fluorescent-antibody test (IFAT)-positive bovine sera against N. caninum from IFAT-negative sera. These results indicate that the ELISA using baculovirus-expressed NcSRS2 can be useful for effective and reliable serodiagnosis of N. caninum infection.