On March 1, the English edition of “China Science: Life Sciences” published the latest research results of the National African Swine Plague Professional Laboratory of Harbin Veterinary Research Institute of the Chinese Academy of Agricultural Sciences. The laboratory in accordance with the Ministry of Agriculture and Rural Affairs and the Chinese Academy of Agricultural Sciences Party Group deployment, relying on veterinary biotechnology national key laboratory and the national animal disease prevention and control high-level biosecurity laboratory, around the African swine plague prevention and control of major strategic needs of the country to carry out scientific and technological research, the creation of an African swine plague weak toxic live vaccine.
The vaccine is good for safety and efficacy in domestic pigs, according to systematic laboratory studies and evaluations.
Gene deficiency detoxifying live vaccine is considered to be the most promising research and development technology for the African swine fever vaccine. Using PigHLJ2018, the first African swine fever virus isolate in China, the researchers constructed a series of recombinant viruses with different genetic deletions using homologous recombination techniques (Figure 1). Through systematic pathogenicity, immunoogenic and immunoprotective tests in pigs, they selected a virus with seven genetic deficiencies (HLJ18-7GD), which meets the safety standards of the weak lysant live vaccine and provides effective immunity protection against lethal attacks on the severe disease of African swine fever (Figure 2).
Figure 1: Construction of candidate vaccines for different gene deletions from african swine fever virus
Figure 2: The seven-gene missing vaccine HLJ18-7GD immunity provides complete protection against the fatal attack of the strong strain of the African swine fever virus
At present, there have been some international research reports on the missing live vaccine of the African swine fever gene. After these vaccination pigs, all produce a higher level of viral emias, the body continued to carry poison for a long time, the risk of toxicity is high, the safety aspects from the industrialization of the application there is a big gap.
In contrast, HLJ18-7GD even after the maximum dose of inoculation of pigs, the vaccine virus can not be copied in the real organs, do not produce viral emias, only in part of the lymph nodes limited replication, about two weeks is completely removed by the body, can not continue to pass on to the body continuously, there is no risk of toxic reflux. In addition, the vaccine for pregnant sows also has good safety, in the early, medium and late stage sin of the vaccine can not cause abortion phenomenon, after-immune delivery of piglets are no different from the non-immune control group.
The team also demonstrated that the vaccine strain can be efficiently cultured in sPF pig primary bone marrow cells, and that a healthy piglet’s primary cell can produce at least 200,000 copies of the vaccine, fully equipped for mass production. The vaccine is the most promising vaccine to realize the application of industrialization, which will provide important technical means for the effective prevention and control of the outbreak of swine fever in China and the countries concerned.
The research results are supported by the key project of “Key Technology for Biosecurity” of the National Key Research and Development Program, the Applied Technology Research and Development Program in Heilongjiang Province and the Science and Technology Innovation Project of the Chinese Academy of Agricultural Sciences. In addition, the study has been the Heilongjiang provincial government and relevant departments of strong support.
Related papers: http://engine.scichina.com/doi/10.1007/s11427-020-1657-9