title: Expression of infectious pancreatic necrosis virus (IPNV) VP2-VP3 fusion protein in Lactobacillus casei and immunogenicity in rainbow trouts.
abstract: Infectious pancreatic necrosis virus (IPNV) infects wild and cultured salmonids, causing high mortality in juvenile trouts and salmons. IPNV VP2-VP3 fusion gene was constructed by splicing overlap extension (SOE) PCR and inserted into Lactobacillus/Escherichia coli shuttle vectors (pPG1and pPG2) followed by transformation of Lactobacillus casei competent cell to yield two recombinant strains: Lc:PG1-VP2-VP3 (surface-displayed) and Lc:PG2-VP2-VP3 (secretory). Subsequently, juvenile rainbow trouts were inoculated with the recombinant strains via orogastric route. Our results demonstrated that Lactobacillus-derived VP2-VP3 fusion protein could induce production of serum IgM specific for IPNV with neutralizing activity in rainbow trouts. Statistical analyses of IgM levels showed that immunogenicity of Lc:PG1-VP2-VP3 was more powerful than that of Lc:PG2-VP2-VP3 (P<0.001) in rainbow trouts. This result has been confirmed by viral loads reduction analyzed by real-time RT-PCR in orogastrically immunized rainbow trouts after virus challenging. Comparing to trouts received Lactobacillus (control), rainbow trouts orogastrically dosed with Lc:PG1-VP2-VP3 resulted in ∼10-fold reduction in viral loads on day 10 post-virus challenging, and ∼4-fold did by Lc:PG2-VP2-VP3. Taken together, Lc:PG1-VP2-VP3 functions as novel mucosal vaccine against IPNV infection in rainbow trouts, which most likely come true.
authors.affiliation: Veterinary Microbiology Department, Veterinary Medicine College, Northeast Agricultural University, Harbin, China.
authors.forename: Li-Li
authors.initials: LL
authors.lastname: Zhao
authors.forename: Min
authors.initials: M
authors.lastname: Liu
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Ge
authors.forename: Xin-Yuan
authors.initials: XY
authors.lastname: Qiao
authors.forename: Yi-Jing
authors.initials: YJ
authors.lastname: Li
authors.forename: Di-Qiu
authors.initials: DQ
authors.lastname: Liu
mesh_terms: D000284:Administration, Oral; D000818:Animals; D057134:Antibodies, Neutralizing / Q000097:blood; D000914:Antibodies, Viral / Q000097:blood; D018175:Birnaviridae Infections / Q000517:prevention & control / Q000662:veterinary*; D005393:Fish Diseases / Q000517:prevention & control* / Q000821:virology; D018928:Immunity, Mucosal; D007075:Immunoglobulin M / Q000097:blood; D018061:Infectious pancreatic necrosis virus / Q000276:immunology; D007780:Lacticaseibacillus casei / Q000276:immunology*; D009500:Neutralization Tests; D017686:Oncorhynchus mykiss / Q000276:immunology* / Q000821:virology; D011993:Recombinant Fusion Proteins / Q000276:immunology; D019562:Viral Load; D015678:Viral Structural Proteins / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000276:immunology*
chemical_list: D057134:Antibodies, Neutralizing; D000914:Antibodies, Viral; D007075:Immunoglobulin M; D011993:Recombinant Fusion Proteins; C509831:VP2 protein, infectious pancreatic necrosis virus; D015678:Viral Structural Proteins; D014765:Viral Vaccines