World's First! Nanjing Agricultural University Successfully Develops Porcine Circovirus Disease Vaccine Using Synthetic Peptide Technology

World's First! Nanjing Agricultural University Successfully Develops Porcine Circovirus Disease Vaccine Using Synthetic Peptide Technology

        Porcine circovirus type 2 (PCV2) is globally recognized as a major disease threatening the swine industry and remains one of the most challenging diseases affecting China's pig farming sector. In June 2021, a research team from Nanjing Agricultural University announced the successful development of a PCV2 vaccine using synthetic peptide technology. According to Professor Jiang Ping, head of the research team and a faculty member at the College of Veterinary Medicine, Nanjing Agricultural University, this marks the first international application of synthetic peptide technology for the immunization and prevention of porcine circovirus disease.

• Identify viral antigen epitopes and design antigenic peptide sequences with high immunogenicity.

     Porcine circovirus type 2 is relatively “invisible.” Although its mortality rate ranges from 10% to 20%, infected pigs generally experience reduced resistance, slowed growth rates, and increased susceptibility to other diseases, posing a threat to the swine industry. Jiang Ping stated that vaccination is currently the most important means of preventing and controlling this disease.

      Previously, vaccines were primarily produced using whole-virus cultivation and genetic engineering methods, requiring both virus cultivation processes and vaccine antigen preparation processes—a time-consuming and labor-intensive production process. Several years ago, Jiang Ping wondered: Could there be an alternative approach beyond these two methods?

      Building on China's previous successful attempts with foot-and-mouth disease vaccines, Jiang Ping wondered whether the “synthetic peptide” method could be used to produce vaccine antigens, thereby improving vaccine production efficiency.

      Synthetic peptide technology is a biochemical method that sequentially and directionally condenses amino acids to form peptides or proteins.

      This requires first identifying the key amino acid sites in pigs infected with porcine circovirus type 2 that trigger an immune response—specifically, the viral antigen epitopes that confer protective immunity. Next, the amino acid combinations forming these epitopes are analyzed to artificially design and synthesize amino acid peptides. When injected into pigs, these peptides enable the animals to develop resistance against porcine circovirus type 2 infection.

      After nearly five years of exploration, Jiang Ping led his team in conducting in-depth research to uncover the virus's interactions with cells, its pathogenic mechanisms, and immune responses. They successfully identified the virus's immunoprotective antigens and antigenic epitopes. Simultaneously, they ingeniously designed and synthesized two peptides composed of 50–65 amino acids, which stimulate pigs to produce antibodies against the virus and confer immunoprotective efficacy.

     Whether peptides offer protective effects in animal organisms varies significantly depending on viral differences. The greatest technical challenge lies in how to arrange and combine key antigenic epitope amino acids to maximize their immunogenic potency. Jiang Ping explained that they have experimented with over 20 combinations of peptide chains. If identifying antigenic epitopes is akin to locating the body's critical ‘sentinels’ for immunity, then designing and synthesizing these two peptides represents assembling an elite defense force. This force can establish a robust immune barrier to resist viral invasion.

• Future efforts will explore the production of synthetic peptide vaccine adjuvants.

       Jiang Ping added that the partner company, Zhongmu Industrial Co., Ltd., developed the peptide solid-phase carrier synthesis method and purification process. This is akin to “establishing” and “reorganizing” a defense force, making it increasingly elite and creating conditions for standardized, large-scale industrial production of the vaccine.
　　Notably, Professor Jiang Ping's team has dedicated nearly two decades to the “research and development of porcine circovirus vaccines.” In 2002, the team isolated the virus from infected pig populations in China. By 2010, they successfully developed China's first inactivated porcine circovirus vaccine, obtaining a Class II New Veterinary Drug Registration Certificate. Subsequently, they developed a water-soluble adjuvant inactivated vaccine for PCV, a trivalent inactivated vaccine combining PCV Type 2 with Haemophilus parasuis and Mycoplasma hyopneumoniae, a recombinant subunit vaccine, and an ELISA antibody detection kit for blocking. These innovations have made significant contributions to promoting the sustainable and healthy development of China's large-scale swine industry and ensuring food safety.

Source of the article:  https://epaper.stdaily.com/statics/technology-site/index.html#/home?isDetail=1&currentNewsId=1f5a8247eb144f71a215da9417e1eb9b&currentVersionName=%E7%AC%AC02%E7%89%88

Email:   jennifer@dilunbio.com