Assessment of the efficacy of two novel DNA vaccine formulations against highly pathogenic Porcine Reproductive and Respiratory Syndrome Virus

Abstract

Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) has emerged and prevailed in mainland China, affecting over 2 million pigs. Commercial PRRSV killed and modified live vaccines cannot provide complete protection against HP-PRRSV due to genetic variation. Development of more effective vaccines against the emerging HP-PRRSV is urgently required. In our previous studies, two formulations of DNA vaccines (pcDNA3.1-PoIFN-λ1-SynORF5 and BPEI/PLGA-SynORF5) based on the HP-PRRSV were constructed and shown to induce enhanced humoral and cellular immune responses in mice. The objective of this study was to evaluate the immune response induced by these novel formulations in piglets. PcDNA3.1-PoIFN-λ1-SynORF5 and BPEI/PLGA-SynORF5 vaccines induced significantly enhanced GP5-specific antibody and PRRSV-specific neutralizing antibody in pigs compared with the pcDNA3.1-SynORF5 parental construct. Though IFN-γ levels and lymphocyte proliferation responses induced by the two DNA vaccine formulations were comparable to that induced by the pcDNA3.1-SynORF5 construct, each of the novel formulations provided efficient protection against challenge with HP-PRRSV. Non-severe clinical signs and rectal temperatures were observed in pigs immunized with BPEI/PLGA-SynORF5 compared with other groups. Thus, these novel DNA constructs may represent promising candidate vaccines against emerging HP-PRRSV.

A flagellin-adjuvanted inactivated porcine epidemic diarrhea virus (PEDV) vaccine provides enhanced immune protection against PEDV challenge in piglets

“…The PBMCs were collected and stimulated with or without PEDV proteins (20 μg/mL), which were prepared by ultracentrifugation of Vero-81 cells infected with PEDV. Lymphocyte proliferation assays were performed as described previously [11]. T-cell stimulation was expressed as the stimulation index (SI), which was calculated as the ratio of the average OD values of the antigenstimulated wells to those of the unstimulated wells.…”

“…Real-time PCR was performed as described previously [19]. Relative IFN-γ gene expression was analyzed as described previously [11], and IFN-γ gene expression was normalized to GAPDH expression. The relative difference in IFN-γ expression among different groups was determined as 2 −∆∆Ct .…”

“…The relative difference in IFN-γ expression among different groups was determined as 2 −∆∆Ct . The genespecific primers used were also described previously [11]: pig-IFN-γ, 5'-AGA ATT GGA AAG AGG AGA GTG ACA A/ TGA ATG GCC TGG TTA TCT TTGA-3'; pig-glyceraldehyde 3-phosphate dehydrogenase (GAPDH), 5'-ACA TGG CCT CCA AGG AGT AAGA/GAT CGA GTT GGG GCT GTG ACT-3'.…”

Complete Genome Sequence of a Novel Subgenotype of Porcine Reproductive and Respiratory Syndrome Virus Strain JX/CH/2016, Isolated in Jiangxi, China

“…In addition, genovariations of PRRSVs have been frequently observed. Recently, several provinces in China reported outbreaks of NADC30-like PRRSVs with genovariations existing in the open reading frame 5 (ORF5) region of the genome of PRRSVs ( 2 , 3 , 7 – 11 ). Herein, we report the full-length genome sequence and molecular characteristics of a novel subgenotype of the PRRSV strain JX/CH/2016 isolated in Jiangxi, China.…”

Development and evaluation of novel recombinant adenovirus-based vaccine candidates for infectious bronchitis virus and Mycoplasma gallisepticum in chickens

“…However, inactivated vaccines do not induce cellular immunity, and attenuated vaccines are associated with the risk of inducing pathogenesis and generating novel viral strains (Ignjatovic et al, 2006;Worthington et al, 2008;Mase et al, 2010). Genetically engineered vaccines can overcome these deficiencies, with bivalent vaccines offering even more advantages, such as reducing inoculation stress and co-delivery of antigen with immunopotentiators (Du et al, 2017). The induction of high antibody levels that provided effective protection from challenge with virulent IBV and MG indicates that pBH-S1-TM-1-EGFP is a promising bivalent candidate vaccine against IB and mycoplasmosis in chickens.…”