Streptococcus suis SBP-bac-5 gene deletion strain and construction method and application thereof

Abstract

The invention discloses a streptococcus suis SBP-bac-5 gene deletion strain and a construction method and application thereof, the streptococcus suis SBP-bac-5 gene deletion strain is SS delta SBP-bac-5 containing no resistance maker, and the preservation number is CGMCC No.10076. Rec A homologous recombination system is used, temperature-sensitive suicide plasmid pSET4s as a carrier is used for deletion of a gene coded by the streptococcus suis type 7 strain SBP-bac-5 to obtain the streptococcus suis SBP-bac-5 gene deletion strain, and SBP-bac-5 protein expression can be destroyed. Compared with a parent strain, the streptococcus suis type 7 SS delta SBP-bac-5 strain is weaker in toxicity and safe to animals. A vaccine is prepared by use of recombinant bacteria for immunization of CD1 mice, the experimental results show that: the streptococcus suis recombinant bacteria vaccine can effectively induce production of specific humoral immune response, so that the immunized mice can be protected against S.suis (streptococcus suis) attacks, and bacteria multiplication in the body can be effectively prevented. The engineering bacteria provides an important basis for the development of vaccine of streptococcus suis vaccines.

Description

technical field [0001] The invention belongs to the technical field of bacterial genetic engineering, and relates to a Streptococcus suis serotype 7 SBP_bac_5 gene deletion strain without a resistance marker, a construction method and application thereof. Background technique [0002] Streptococcus suis (S.suis) is a Gram-positive coccus and an important zoonotic pathogen. In 1998 and 2005, two large-scale outbreaks of S. suis disease in pigs and humans occurred in China. A total of 204 cases of S. suis infection in humans were reported, including 38 deaths, which seriously affected public health safety. So far, there is still no effective vaccine for the prevention of this disease. Current research shows that there are more than 35 serotypes of S. suis capsular antigen, among which serotype 2 is the main pathogenic bacteria type in the world. However, in recent years, S. suis type 7 has been frequently reported in the detection of diseased pigs all over the world, and its...

AI Technical Summary

Problems solved by technology

[0004] The current commercialized whole-bacteria inactivated vaccines and subunit vaccines can alleviate the clinical symptoms and mortality caused by homologous serotypes, but they cannot prevent tissue lesions and chronic infections, and cannot provide complete protection against heterologous serotypes. cross protection

Therefore, the use of inactivated vaccines and subunit vaccines is not the best choice, and there is an urgent need for safer and more efficient new vaccines to prevent and control the occurrence and prevalence of this infectious disease

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