title: A 78 kDa host cell invasion protein of Neospora caninum as a potential vaccine candidate.
abstract: Neosporosis is an intracellular protozoan disease caused by Neospora caninum. Until now, there is no effective vaccine to prevent neosporosis. The host cell binding protein has the potential as neosporosis vaccine. In the present study, a T7 phage display library was constructed and screened using Vero cells to obtain host cell binding protein of N. caninum. Two host cell binding proteins, a hypothetical protein of 78 kDa (named as NcP78) homologous to the acylglycerol lipase of Toxoplasma gondii ME49 (XP_002370319.1) and NcGRA7 (known as a dense granules protein that is involved in the invasion of N. caninum to the host cells), were identified. Immune responses induced by recombinant NcP78 and NcGRA7 proteins and their protective efficacies against homologous challenge in BALB/c mice were evaluated respectively. Results showed that recombinant NcP78 and NcGRA7 could elicit both Th1 and Th2 immune responses (with the elevated levels of IgG1 and IgG2a antibody), but predominately a Th2 immune response with a high level of IgG1. The ani-NcP78 and anti-NcGRA7 serum also had inhibitory effects on N. caninum invasion to Vero cells in vitro, which indicated that both NcP78 and NcGRA7 proteins were involved in host cell invasion. Recombinant NcP78 and NcGRA7 could not prolong the survival times and improve the survival rates of dams, but could prolong the survival times and improve the survival rates of offspring significantly. Moreover, the recombinant NcP78 and NcGRA7 could reduce the brain parasite load of dams and offspring. Though these protein vaccines could not effectively alleviate the symptom of abortion, they could increase the number of born offspring significantly, indicating that Nc78 and NcGRA7 recombinant proteins could provide a partial protection against N. caninum infection in mice.
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China; Key Laboratory of Polymer Ecomaterials, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, China.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Lv
authors.affiliation: College of Animal Science of Jilin University, 5333 Xian Road, Changchun 130062, China.
authors.forename: Shenyang
authors.initials: S
authors.lastname: Xing
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China.
authors.forename: Pengtao
authors.initials: P
authors.lastname: Gong
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China.
authors.forename: Le
authors.initials: L
authors.lastname: Chang
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China.
authors.forename: Zhengzheng
authors.initials: Z
authors.lastname: Bian
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China.
authors.forename: Lidong
authors.initials: L
authors.lastname: Wang
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China. Electronic address: zhangxic@public.cc.jl.cn.
authors.forename: Xichen
authors.initials: X
authors.lastname: Zhang
authors.affiliation: College of Veterinary Medicine of Jilin University, 5333 Xian Road, Changchun 130062, China. Electronic address: jianhuali7207@163.com.
authors.forename: Jianhua
authors.initials: J
authors.lastname: Li
mesh_terms: D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood; D001921:Brain / Q000469:parasitology; D002522:Chlorocebus aethiops; D003048:Coccidiosis / Q000401:mortality / Q000517:prevention & control / Q000662:veterinary*; D005260:Female; D005786:Gene Expression Regulation; D007106:Immune Sera / Q000276:immunology; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D051379:Mice; D018688:Neospora / Q000276:immunology*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology* / Q000378:metabolism; D016052:Protozoan Vaccines; D011897:Random Allocation; D013047:Specific Pathogen-Free Organisms; D014709:Vero Cells
chemical_list: D000913:Antibodies, Protozoan; D007106:Immune Sera; D007074:Immunoglobulin G; D015800:Protozoan Proteins; D016052:Protozoan Vaccines
keywords: Immune response; NcGRA7; NcP78; Neospora caninum; Protective efficacy; T7 phage display library