Study of the immunogenicity of the VP2 protein of canine parvovirus produced using an improved Baculovirus expression system

Abstract

Background: Canine parvovirus (CPV) is now recognized as a serious threat to the dog breeding industry worldwide. Currently used CPV vaccines all have their specific drawbacks, prompting a search for alternative safe and effective vaccination strategies such as subunit vaccine. VP2 protein is the major antigen targeted for developing CPV subunit vaccine, however, its production in baculovirus expression system remains challenging due to the insufficient yield. Therefore, our study aims to increase the VP2 protein production by using an improved baculovirus expression system and to evaluate the immunogenicity of the purified VP2 protein in mice. Results: The results showed that high-level expression of the full length VP2 protein was achieved using our modified baculovirus expression system. The recombinant virus carrying two copies of VP2 gene showed the highest expression level, with a productivity of 186 mg/L, which is about 1.4-1.6 fold that of the recombinant viruses carrying only one copy. The purified protein reacted with Mouse anti-His tag monoclonal antibody and Rabbit anti-VP2 polyclonal antibody. BALB/c mice were intramuscularly immunized with purified VP2 protein twice at 2 week intervals. After vaccination, VP2 protein could induce the mice produce high level of hemagglutination inhibition antibodies. Conclusions: Full length CPV VP2 protein was expressed at high level and purified efficiently. Moreover, it stimulated mice to produce high level of antibodies with hemmaglutination inhibition properties. The VP2 protein expressed in this study could be used as a putative economic and efficient subunit vaccine against CPV infection.

Expression of the VP2 protein of feline panleukopenia virus in insect cells and use thereof in a hemagglutination inhibition assay

“…PCR amplification of the VP2 gene has been used to detect wild FPV [21]. VP2 has been expressed in several hosts, including E. coli [22], insect cells [16,23,24], and a plant [25], for use as a subunit vaccine. We expressed VP2 in a baculovirus system, as revealed by IFA, WB, EM, and an HA test.…”

“…Baculovirus expression systems yield high levels of recombinant proteins and virus-like particles (VLPs) [15]. Several recombinant baculoviruses expressing VP2 of CPV and FPV have been created [16,17]. The recombinant VP2 proteins form VLPs via self-assembly and serve as antigens for subunit vaccines, enzyme-linked immunosorbent assays (ELISAs) [17,18], and HI tests.…”

Self-assembled raccoon dog parvovirus VP2 protein confers immunity against RDPV disease in raccoon dogs: in vitro and in vivo studies

“…VLPs mimic virus particles and present considerable epitopes and are, therefore, capable of stimulating multiple immune responses [ 17 ]. Previous studies have shown that a variety of VLPs protein could be expressed in various expression systems, such as mammalian, insects, yeast, and E. coli [ 4 , 12 , 14 , 16 , 20 , 29] . To the best of our knowledge, there are no reports on the expression of RDPV VP2 till date.…”

Isolation and molecular characterization of feline panleukopenia viruses from Korean cats

“…The 4th ORF encodes VP2; this is the major capsid protein (constituting approximately 90% of the entire capsid). VP2 controls the host range and contains several important B cell epitopes that induce protective (neutralizing) antibodies during infection [6]. Of the 4 ORFs, the one encoding VP2 has been most commonly ex-…”