Construction and immunogenicity of a DNA vaccine coexpressing GP3 and GP5 of genotype-I porcine reproductive and respiratory syndrome virus

Abstract

BackgroundThe European (EU) genotype of porcine reproductive and respiratory syndrome virus (Genotype-I PRRSV) has recently emerged in China. The coexistence of Genotype-I and -II PRRSV strains could cause seriously affect PRRSV diagnosis and management. Current vaccines are not able to protect against PRRSV infection completely and have inherent drawbacks. Thus, genetically engineered vaccines, including DNA vaccine and live vector engineered vaccines, have been developed. This study aimed to determine the enhanced immune responses of mice inoculated with a DNA vaccine coexpressing GP3 and GP5 of a Genotype-I PRRSV.ResultsTo evaluate the immunogenicity of GP3 and GP5 proteins from European-type PRRSV, three DNA vaccines, pVAX1-EU-ORF3-ORF5, pVAX1-EU-ORF3 and pVAX1-EU-ORF5, were constructed, which were based on a Genotype-I LV strain (GenBank ID: M96262). BALB/c mice were immunized with the DNA vaccines; delivered in the form of chitosan-DNA nanoparticles. To increase the efficiency of the vaccine, Quil A (Quillaja) was used as an adjuvant. GP3 and GP5-specific antibodies, neutralizing antibodies and cytokines (IL-2, IL-4, IL-10 and IFN gamma) from the immunized mice sera, and other immune parameters, were examined, including T-cell proliferation responses and subgroups of spleen T-lymphocytes. The results showed that ORF3 and ORF5 proteins of Genotype-I PRRSV induced GP3 and GP5-specific antibodies that could neutralize the virus. The levels of Cytokines IL-2, IL-4, IL-10, and IFN–γ of the experimental groups were significantly higher than those of control groups after booster vaccination (P < 0.05). The production of CD3+CD4+ and CD3+CD8+ T lymphocyte was also induced. T lymphocyte proliferation assays showed that the PRRSV LV strain virus could stimulate the proliferation of T lymphocytes in mice in the experimental group.ConclusionsUsing Quil A as adjuvant, Genotype-I PRRSV GP3 and GP5 proteins produced good immunogenicity and reactivity. More importantly, better PRRSV-specific neutralizing antibody titers and cell-mediated immune responses were observed in mice immunized with the DNA vaccine co-expressing GP3 and GP5 proteins than in mice immunized with a DNA vaccine expressing either protein singly. The results of this study demonstrated that co-immunization with GP3 and GP5 produced a better immune response in mice.

Construction and immunogenicity of a recombinant swinepox virus expressing a multi-epitope peptide for porcine reproductive and respiratory syndrome virus

“…The role of NA in protection against PRRSV infection was demonstrated in pigs by passive antibody transfer 10 . Several viral targets that play a role in the induction of NA have been reported, including GP3, GP4, GP5, and M proteins 11 12 13 14 .…”

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

“…Killed vaccines are weakly immunogenic and MLVs has the potential revert to high virulence 21 22 23 . DNA vaccines are the third revolution in the vaccine field, and have been found to be safe to the host while generating both humoral and cellular immunity 24 25 . Moreover, DNA vaccines can be easily modified to enhance the poor immunogenicity.…”

“…In order to increase the efficiency of the PRRSV vaccines, they were modified with immunopotentiators, including HSP70 26 , IL-18 8 , GM-CSF 27 , CD40L 28 , CpG oligodeoxynucleotides 29 30 , IL-2 31 , CTLA4 32 and interferon α/β 33 . Furthermore, delivery systems were also applied to the design of PRRSV vaccines, for example, viral vectors 34 35 36 , chitosan 25 37 and poly(lactic-co-glycolic acid) (PLGA) 38 39 40 41 . In our previous studies, an immunopotentiator (PoIFN-λ1) and delivery system (BPEI/PLGA) were applied to modify pcDNA3.1-SynORF5 constructs, based on the HP-PRRSV JSKM strain.…”

Construction and Immunogenicity of Recombinant Vaccinia Virus Vaccine Against Japanese Encephalitis and Chikungunya Viruses Infection in Mice

“…Spleen lymphocytes were isolated using the mice lymphocyte isolation solution kit (Hao Yang Biological Manufacturers, Tian Jin, China), following supplier's instructions at 35 dpi. Lymphocyte concentration was adjusted to 1 • 10 5 / well and proliferation was measured as previously reported (Ren et al 2014). Each sample was stimulated with 50 lL of inactivated CHIKV or JEV antigen (10 lg/mL) in triplicate.…”

“…Murine spleen cells were isolated using mice lymphocyte isolation solution kit (Hao Yang Biological Manufacturers, Tianjin, China), according to manufacturer's instructions at 35 dpi. Percentages of CD3 + CD4 + and CD3 + CD8 + T lymphocytes were measured as previously reported (Ren et al 2014). PE anti-mouse CD8, PE/Cy5 anti-mouse CD3, and FITC anti-mouse CD4 (BioLegend, San Diego, CA) antibodies were used for each sample.…”