Porcine reproductive and respiratory syndrome virus chimeric recombinant vaccine strain and method for producing living vaccine with same

Abstract

The invention relates to a porcine reproductive and respiratory syndrome virus chimeric recombinant vaccine strain and a method for producing living vaccine with same; latter half part of GP2 gene and GP3-GP5 gene of the porcine reproductive and respiratory syndrome virus (PRRSV) classic virus PTK strain, M ferritin, N ferritin and spacer sequences thereof and all nucleotide sequences of 3' non-coding region are all deleted by using reverse genetic manipulation and gene combination technology, then replaced with corresponding gene of Chinese highly pathogenic porcine reproductive and respiratory syndrome variant strain and are recombined to be the chimeric recombinant vaccine strain (PC strain) with the PRRSV classic strain and variant strain genes simultaneously, the chimeric recombinant vaccine PC strain is used to produce the living vaccine which has low toxicity, ensures no returning of strong toxicity within 5 generations of returning swine and the heritability is stable; the invention has good immunogenicity, and can prevent the porcine reproductive and respiratory syndrome virus classic strain and highly pathogenic variant strain from being infected simultaneously.

Description

technical field [0001] The invention belongs to the technical field of veterinary biological products, and in particular relates to a method for constructing attenuated live vaccine strains by gene recombination technology and using the strains to produce live porcine reproductive and respiratory syndrome vaccines. Background technique [0002] Pig PRRS is a disease caused by porcine reproductive and respiratory syndrome virus (PRRSV), which is clinically characterized by fever, abortion, increased mortality of piglets before and after weaning, and respiratory disorders in pigs of different ages. In 1991, Dutch scholar Terpstra et al. isolated European-type PRRSV from infected pigs and named it Lelystad virus (Lv); in the same year, American scholar Benfield et al. isolated American-type PRRSV and named it VR-2332. In recent years, Chinese scholars have successively isolated and identified strains such as CH-1a, S1, HB-1 and HB-2 of the American PRRSV. [0003] Pig "high fe...

AI Technical Summary

Problems solved by technology

[0025] Although there are many types of vaccines against PRRS, none of them can produce ideal safety protection in pigs

[0026] The research and development of porcine reproductive and respiratory syndrome (or porcine PRRS) vaccines is a worldwide problem. Live vaccines generally have the problem of strong virulence, while the main problem of inactivated vaccines is poor immune efficacy

At present, there is no satisfactory vaccine for the prevention of this disease in the world

And the highly pathogenic PRRS virus that appeared in my country in 2006, due to the mutation of the pathogenic gene, the classic PRRS vaccine basically has no immune protection to it. The inactivated vaccines produced also cannot effectively protect the wild strains, and the production of attenuated vaccines from the weakened strains also has the problem of virulence

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