Recombinant porcine circovirus type 2 virus-like particle, and preparation method and application thereof

Abstract

The invention discloses a recombinant porcine circovirus type 2 (PCV2) virus-like particle (VLP). The VLP is prepared by connecting a protein transduction domain originated from HSV-1VP22 with an antigen Cap gene needed for formation of PCV2 hollow capsid protein by using an SOE-PCR method, then carrying out cloning to a baculovirus transporter so as to obtain a homologous recombinant vector, carrying out encapsulation so as to produce recombinant baculovirus containing PCV2Cap protein and the protein transduction domain of HSV-1VP22, infecting an insect cell and expressing recombinant Cap-VP22 protein in which PCV2Cap protein and the protein transduction domain of HSV-1VP22 are fused. According to results of research, the VLP prepared in the invention can be individually used or used with adjuvant for inoculation to an animal and effectively stimulates generation of a specific antibody to PCV2. Thus, the VLP provided by the invention can be applied to development of a novel high-efficiency PCV2 subunit vaccine with a good immune effect.

Description

technical field [0001] The invention belongs to the technical field of porcine circovirus type 2, and in particular relates to a recombinant porcine circovirus type 2 virus-like particle and a preparation method and application thereof. Background technique [0002] Porcine circovirus (PCV) was discovered as a culture pollutant of porcine kidney cell line PK-15. Its genome is a covalently closed single-stranded circular DNA molecule with a total genome length of about 1.7kb. PCV is the smallest animal virus discovered so far. Virus particles have no envelope on the surface, are icosahedrally symmetrical, and have particle diameters between 17-20nm. According to the pathogenicity, serotype and genotype characteristics of PCV, it can be divided into two types: non-pathogenic PCV1 and pathogenic PCV2. Among them, PCV2 is the main pathogen causing porcine circovirus disease (PCVD). The full length of the PCV2 genome is 1767bp or 1768bp, consisting of 11 open reading frames (OR...

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Problems solved by technology

However, due to the shortcomings of inactivated vaccines such as short duration of immunity, large side effects of immunization injection, and inability to stimulate the body to produce cellular immunity, the immune effect is not satisfactory.

Attenuated vaccines can usually induce solid immunity and long-lasting protection in the body. However, attenuated vaccines are easy to reverse their virulence, and it is difficult to evaluate attenuated virulence. There are hidden dangers in safety. Therefore, there are few reports on research on PCV2 attenuated vaccines at home and abroad.

DNA vaccines have many advantages such as simple preparation and good immune effect, but due to the lack of efficient gene delivery system, the expression regulation of exogenous genes in vivo and their transfer between somatic cells may cause unexpected immunopathological reactions and other bottleneck problems Difficult breakthroughs keep most DNA vaccine research confined to labs

Some other recombinant virus vaccines and subunit vaccines have a certain protective effect on PCV2, but they are still in the research and development stage due to various reasons such as low safety and poor immune effect.

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