title: Vaccine efficacy of a cell lysate with recombinant baculovirus-expressed feline infectious peritonitis (FIP) virus nucleocapsid protein against progression of FIP.
abstract: The Type II feline infectious peritonitis virus (FIPV) infection of feline macrophages is enhanced by a monoclonal antibody (MAb) to the S protein of FIPV. This antibody-dependent enhancement (ADE) activity increased with the MAb that showed a neutralizing activity with feline kidney cells, suggesting that there was a distinct correlation between ADE activity and the neutralizing activity. The close association between enhancing and neutralizing epitopes is an obstacle to developing a vaccine containing only neutralizing epitopes without enhancing epitopes. In this study, we immunized cats with cell lysate with recombinant baculovirus-expressed N protein of the Type I FIPV strain KU-2 with an adjuvant and investigated its preventive effect on the progression of FIP. Cats immunized with this vaccine produced antibodies against FIPV virion-derived N protein but did not produce virus-neutralizing antibodies. A delayed type hypersensitivity skin response to N protein was observed in these vaccinated cats, showing that cell mediated immunity against the FIPV antigen was induced. When these vaccinated cats were challenged with a high dose of heterologous FIPV, the survival rate was 75% (6/8), while the survival rate in the control group immunized with SF-9 cell-derived antigen was 12.5% (1/8). This study showed that immunization with the cell lysate with baculovirus-expressed N protein was effective in preventing the progression of FIP without inducing ADE of FIPV infection in cats.
authors.affiliation: Department of Veterinary Infectious Diseases, School of Veterinary Medicine and Animal Sciences, Kitasato University, Towada, Aomori 034, Japan. hohdatsu@vmas.kitasato-u.ac.jp
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Hohdatsu
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamato
authors.forename: Tasuku
authors.initials: T
authors.lastname: Ohkawa
authors.forename: Miyuki
authors.initials: M
authors.lastname: Kaneko
authors.forename: Kenji
authors.initials: K
authors.lastname: Motokawa
authors.forename: Hajime
authors.initials: H
authors.lastname: Kusuhara
authors.forename: Takashi
authors.initials: T
authors.lastname: Kaneshima
authors.forename: Setsuo
authors.initials: S
authors.lastname: Arai
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Koyama
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D000956:Antigens, Viral / Q000276:immunology; D016367:Baculoviridae / Q000235:genetics; D002415:Cats; D016765:Coronavirus, Feline / Q000276:immunology*; D004797:Enzyme-Linked Immunosorbent Assay; D016766:Feline Infectious Peritonitis / Q000276:immunology* / Q000517:prevention & control; D006968:Hypersensitivity, Delayed / Q000276:immunology; D009500:Neutralization Tests / Q000662:veterinary; D019590:Nucleocapsid Proteins / Q000235:genetics / Q000276:immunology*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012680:Sensitivity and Specificity; D013047:Specific Pathogen-Free Organisms; D014611:Vaccination / Q000662:veterinary*; D014765:Viral Vaccines / Q000276:immunology* / Q000592:standards
chemical_list: D000914:Antibodies, Viral; D000956:Antigens, Viral; D019590:Nucleocapsid Proteins; D011994:Recombinant Proteins; D014765:Viral Vaccines