Improvement of the Immunogenicity of Porcine Circovirus Type 2 DNA Vaccine by Recombinant ORF2 Gene and CpG Motifs

Abstract

Nowadays, adjuvant is still important for boosting immunity and improving resistance in animals. In order to boost the immunity of porcine circovirus type 2 (PCV2) DNA vaccine, CpG motifs were inserted. In this study, the dose-effect was studied, and the immunity of PCV2 DNA vaccines by recombinant open reading frame 2 (ORF2) gene and CpG motifs was evaluated. Three-week-old Changbai piglets were inoculated intramuscularly with 200 μg, 400 μg, and 800 μg DNA vaccines containing 14 and 18 CpG motifs, respectively. Average gain and rectum temperature were recorded everyday during the experiments. Blood was collected from the piglets after vaccination to detect the changes of specific antibodies, interleukin-2, and immune cells every week. Tissues were collected for histopathology and polymerase chain reaction. The results indicated that compared to those of the control piglets, all concentrations of two DNA vaccines could induce PCV2-specific antibodies. A cellular immunity test showed that PCV2-specific lymphocytes proliferated the number of TH, TC, and CD3+ positive T-cells raised in the blood of DNA vaccine immune groups. There was no distinct pathological damage and viremia occurring in pigs that were inoculated with DNA vaccines, but there was some minor pathological damage in the control group. The results demonstrated that CpG motifs as an adjuvant could boost the humoral and cellular immunity of pigs to PCV2, especially in terms of cellular immunity. Comparing two DNA vaccines that were constructed, the one containing 18 CpG motifs was more effective. This is the first report that CpG motifs as an adjuvant insert to the PCV2 DNA vaccine could boost immunity.

Immunogenicity of porcine circovirus type 2 nucleic acid vaccine containing CpG motif for mice

“…Our previous research demonstrated that CpG motifs as an adjuvant could boost the humoral and cellular immunity of pigs to against PCV2, especially in terms of cellular immunity [10]. This study evaluated the adjuvant of CpG motifs to PCV2 DNA vaccine and mainly detected the serum antibody levels in mice by ELISA.…”

“…The current research on CpG as immune adjuvant was mainly focused on the mouse and human disease. Based on the earlier research in the authors ‘laboratory (Cheng KH, “Study on Series of DNA Vaccines Against Porcine Circovirus Type 2[D],”[master’s thesis QingDao Agricultural University, 2009]), we first reported the CpG motifs as an adjuvant insert to the PCV2 DNA vaccine that could boost immunity in pigs [10]. …”

“…In this study,we evaluate immune effect of PCV2 DNA vaccine with CpG motif on mice using the best CpG motif from our earlier research [10], which can provide a great prospect for preventing and controlling PCVD,in order to give candidate vaccine evaluation model.…”

Advances in Non-Viral DNA Vectors for Gene Therapy

“…CpG motifs have been encoded within plasmid DNA vaccines [ 108 , 109 ], or co-delivered with DNA vaccines on either other DNA vectors [ 110 ] or oligonucleotides (reviewed in [ 111 , 112 ]). Miniplasmid vectors have demonstrated utility as improved DNA vaccines [ 37 , 38 , 39 ].…”

DNA vaccines for prostate cancer

“…Binding of unmethylated CpG DNA to TLR9 results in the release of type I IFNs and in some contexts proinflammatory cytokines (Sasai et al,2010; Wagner, 2004). Studies examining the role of TLR9 signaling in DNA vaccine immunogenicity suggested that it may play a role in the enhancement of adaptive immune responses, but is not necessary for their induction (Babiuk et al, 2004; Chen et al, 2015; Li et al, 2015; Mitsui et al, 2009; Schneeberger et al, 2004; Stan et al, 2001). In our own preclinical and clinical studies with DNA vaccines encoding tumor antigens, we have enhanced TLR9 signaling by using a plasmid vector (pTVG4) whose backbone was modified to contain CpG-rich sequences (Becker et al, 2010a; McNeel et al, 2009a; Rekoske et al, 2015; Smith & McNeel, 2011).…”