Method for preparing porcine circovirus 2 open reading frame 2 (ORF2) protein

Abstract

The invention discloses a method for preparing a porcine circovirus 2 open reading frame 2 (ORF2) protein. A Cap gene of an encoding porcine circovirus 2 (PCV2) nucleocapsid protein is connected to a pET-28a(+) plasmid to build an expression plasmid pET-28-Cap, and a BL21(DE3) competent cell is converted to obtain a genetic engineering strain pET-28-Cap / BL21. Induction expression and detection prove that the recombinant protein has good reactionogenicity; furthermore, the protein can be used for diagnosing antigen or preparing subunit vaccines; and the product can be expressed in Escherichia coli in a soluble manner, the expression quantity is large and a complicated process of albuminous degeneration repeatability is avoided, and the loss and production cost of the protein are lowered.

Description

technical field [0001] The invention relates to a method for preparing porcine type II circovirus ORF2 protein. Background technique [0002] Porcine circovirus type II (PCV2) is one of the newly discovered animal viruses in recent years. It belongs to the Circoviridae family. , is the smallest animal virus found so far. The disease was first discovered in western Canada in 1991, and is divided into PCV-1 and PCV-2 according to the pathogenicity. Among them, PCV-2 has strong infectivity to pigs, and can infect pigs of different ages through the oral and respiratory routes, causing multisystemic wasting syndrome (PMWS) in weaned piglets. Infected pigs have progressive emaciation, sluggishness, dyspnea, jaundice, pale skin, and even death. Etiological and serological investigations have shown that the disease is widespread in many countries and has caused great losses to the world's pig industry. [0003] The PCV-2 genome contains ORF1 and ORF2. ORF1 encodes the Rep protein...

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Problems solved by technology

[0005] Porcine circovirus type II (PCV2) cell culture inactivated vaccine yield is low and the country lacks a unified production and inspection method and standard for PCV2 vaccine. These problems have become bottlenecks that limit the development and application of this type of product; new vaccines such as DNA vaccine , the immune efficiency has yet to be confirmed, and subunit vaccines have been marketed abroad, which can significantly reduce viremia, but are expensive

[0006] In porcine type II circovirus ORF2 protein subunit vaccine, there have been reports on the use of yeast and baculovirus to express ORF2 protein, but the yeast expression system is cumbersome, and there may be problems with protein cleavage, while baculovirus has high expression costs, Disadvantages such as difficulty in protein purification

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