title: Construction of recombinant lactobacilli expressing the core neutralizing epitope (COE) of porcine epidemic diarrhea virus and a fusion protein consisting of COE and  Escherichia coli  heat-labile enterotoxin B, and comparison of the immune responses by orogastric immunization.
abstract: The core neutralizing epitope (COE) region of porcine epidemic diarrhea virus (PEDV) plays an important role in the development of the subunit vaccine against PEDV infection. To enhance the vaccine's immunogenicity,  Escherichia coli  heat-labile enterotoxin B (LTB) has usually been adopted as a molecular adjuvant. In this study, the COE and LTB-COE genes were engineered into the  Lactobacillus -Escherichia coli shuttle vectors pSAPG1 (surface-displaying) and pSAPG2 (secreting) followed by electrotransformation into  Lactobacillus casei  (Lc) to yield the following recombinant strains: Lc:PG1-LTB-COE, Lc:PG2-LTB-COE, Lc:PG1-COE, and Lc:PG2-COE. Our results showed that mice immunized orogastrically with L. casei expressing COE or LTB-COE produced secretory immunoglobulin A and immunoglobulin G with the ability to neutralize PEDV in sera and mucus. Moreover, higher levels of interleukin-4 and gamma interferon were also exhibited compared with negative control. These data displayed the tendency of Lc:PG2-LTB-COE > Lc:PG1-LTB-COE > Lc:PG2-COE > Lc:PG1-COE at the same time point. Taken together, LTB-COE is more suitable for Lactobacillus expressing system to engineer mucosal vaccine against PEDV infection.
authors.affiliation: Veterinary Microbiology Department, Veterinary Medicine College, Northeast Agricultural University, Harbin, People's Republic of China.
authors.forename: Jun-Wei
authors.initials: JW
authors.lastname: Ge
authors.forename: Di-Qiu
authors.initials: DQ
authors.lastname: Liu
authors.forename: Yi-Jing
authors.initials: YJ
authors.lastname: Li
mesh_terms: D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D002522:Chlorocebus aethiops; D016207:Cytokines / Q000032:analysis; D004768:Enterotoxins / Q000235:genetics* / Q000276:immunology*; D000939:Epitopes / Q000235:genetics / Q000276:immunology; D004926:Escherichia coli / Q000235:genetics; D005260:Female; D007114:Immunization; D007071:Immunoglobulin A, Secretory / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007778:Lactobacillus / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D053485:Porcine epidemic diarrhea virus / Q000235:genetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology*; D014709:Vero Cells
chemical_list: D000914:Antibodies, Viral; D016207:Cytokines; D004768:Enterotoxins; D000939:Epitopes; D007071:Immunoglobulin A, Secretory; D007074:Immunoglobulin G; D011994:Recombinant Proteins