title: Immunogenicity of Lactobacillus-expressing VP2 and VP3 of the infectious pancreatic necrosis virus (IPNV) in rainbow trout.
abstract: Infectious pancreatic necrosis virus (IPNV) infects salmonid fish with high mortality and causes serious economic losses to salmonid aquaculture. Lactobacillus strains have a number of properties that make them attractive candidates as delivery vehicles for the presentation to the mucosa of compounds with pharmaceutical interest, in particular vaccines. Here, Lactobacilli/Escherichia coli shuttle vector pPG1 (surface-displayed) or pPG2 (secretory) with the capsid VP2 gene inserted was transformed into Lactobacillus casei to yield two recombinant strains: Lc:PG1-VP2 and Lc:PG2-VP2, respectively. Rainbow trout immunized respectively with Lc:PG1-VP2, Lc:PG2-VP2, Lc:PG1-VP3 and Lc:PG2-VP3 elicited anti-IPNV immune responses (serum IgM) via oral route. Statistical results of serum IgM titer with neutralizing activity showed that immunogenicity of Lc:PG2-VP2 was more powerful than that of Lc:PG1-VP2 (P < 0.001), Lc:PG1-VP3 (P < 0.001) and Lc:PG2-VP3 (P < 0.001), which was confirmed by viral loads reduction analyzed by real-time RT-PCR in orally immunized rainbow trout after virus challenge. Comparing with negative control, rainbow trout orally dosed with Lc:PG2-VP2 resulted in ∼46-fold reduction in virus load on days 10 post viral challenge as well as Lc:PG1-VP2(∼20-fold), Lc:PG2-VP3(∼6-fold) and Lc:PG1-VP3(∼3-fold). Taken together, Lc:PG2-VP2 exhibited a more appropriate candidate as live bacteria vaccine against IPNV infection in rainbow trout.
authors.affiliation: Veterinary Microbiology Department, Veterinary Medicine College, Northeast Agricultural University, Harbin 150030, PR China.
authors.forename: Liu
authors.initials: L
authors.lastname: Min
authors.forename: Zhao
authors.initials: Z
authors.lastname: Li-Li
authors.forename: Ge
authors.initials: G
authors.lastname: Jun-Wei
authors.forename: Qiao
authors.initials: Q
authors.lastname: Xin-Yuan
authors.forename: Li
authors.initials: L
authors.lastname: Yi-Jing
authors.forename: Liu
authors.initials: L
authors.lastname: Di-Qiu
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D018175:Birnaviridae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D005393:Fish Diseases / Q000276:immunology* / Q000517:prevention & control; D018061:Infectious pancreatic necrosis virus / Q000235:genetics / Q000276:immunology; D007778:Lactobacillus / Q000235:genetics; D017686:Oncorhynchus mykiss / Q000276:immunology / Q000821:virology; D019562:Viral Load; D014765:Viral Vaccines / Q000276:immunology*
chemical_list: D000914:Antibodies, Viral; D014765:Viral Vaccines