title: High-level mucosal and systemic immune responses induced by oral administration with Lactobacillus-expressed porcine epidemic diarrhea virus (PEDV) S1 region combined with Lactobacillus-expressed N protein.
abstract: To develop effective mucosal vaccine formulation against porcine epidemic diarrhea virus (PEDV) infection, the DNA fragments encoding spike protein immunodominant region S1 and nucleocapsid N of PEDV were inserted into pPG1 (surface-displayed) or pPG2 (secretory) plasmids followed by electrotransformation into Lactobacillus casei (Lc) to yield four recombinant strains: PG1-S1, PG2-S1, PG1-N, and PG2-N. After intragastric administration, it was observed that live Lc-expressing S1 protein combined with Lc-expressing N protein could elicit much more potent mucosal and systemic immune responses than the former alone (P < 0.001), however slightly inferior to the latter alone (P > 0.05). Furthermore, the surface-displayed mixture (PG1-S1+ PG1-N) revealed stronger immunogenicity than the secretory mixture (PG2-S1+ PG2-N) as well as PEDV-neutralizing potency in vitro (P < 0.001). On 49th day after the last immunization, splenocytes were prepared from mice immunized with surface-displayed mixture, secretory mixture and negative control to be stimulated by purified N and S protein, respectively. The results of ELISA analysis showed that N protein was capable of inducing a higher level of IL-4 (P < 0.001) and IFN-γ (P < 0.001) than S1 protein in the immunized mice. Taken together, Lc-expressed N protein as molecular adjuvant or immunoenhancer was able to effectively facilitate the induction of mucosal and systemic immune responses by Lc-expressing S1 region.
authors: Veterinary Microbiology Department, Veterinary Medicine College, Northeast Agricultural University, Harbin, People's Republic of China.
authors: Di-qiu
authors: DQ
authors: Liu
authors: Jun-wei
authors: JW
authors: Ge
authors: Xin-yuan
authors: XY
authors: Qiao
authors: Yan-ping
authors: YP
authors: Jiang
authors: Song-mei
authors: SM
authors: Liu
authors: Yi-jing
authors: YJ
authors: Li
mesh_terms: D000284:Administration, Oral; D000818:Animals; D018352:Coronavirus Infections / Q000276:immunology / Q000662:veterinary* / Q000821:virology; D000086462:Coronavirus Nucleocapsid Proteins; D005260:Female; D015870:Gene Expression; D018928:Immunity, Mucosal; D007778:Lactobacillus / Q000235:genetics* / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D051379:Mice; D008807:Mice, Inbred BALB C; D019590:Nucleocapsid Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D053485:Porcine epidemic diarrhea virus / Q000235:genetics / Q000276:immunology*; D064370:Spike Glycoprotein, Coronavirus; D013552:Swine; D013553:Swine Diseases / Q000276:immunology* / Q000517:prevention & control / Q000821:virology; D014759:Viral Envelope Proteins / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D014765:Viral Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D000086462:Coronavirus Nucleocapsid Proteins; D008562:Membrane Glycoproteins; D019590:Nucleocapsid Proteins; D064370:Spike Glycoprotein, Coronavirus; D014759:Viral Envelope Proteins; D014765:Viral Vaccines; C578557:spike glycoprotein, SARS-CoV; C578553:spike protein, mouse hepatitis virus