O-type foot-and-mouth disease virus acid-resistant mutant strain, its capsid protein and its encoding gene and application

Abstract

The invention discloses an O-type foot and mouth disease virus acid-resistant mutant strain, a capsid protein carried by the O-type foot and mouth disease virus acid-resistant mutant strain and a coding gene of the capsid protein and also discloses a key amino acid site for determining O-type foot and mouth disease virus acid-resistant characteristics and a use of the key amino acid site. An O-type foot and mouth disease virus parent strain is subjected to serial passage screening under acid stress so that a mutant strain having strong acid resistance is obtained, and an analysis result shows that a VP1 N17D mutational site is a key amino acid site for determining O-type foot and mouth disease virus acid-resistant characteristics, the O-type foot and mouth disease virus only with the VP1 N17D mutational site has the acid resistance the same as that of the mutant strain and also has a good replication capability and immunogenicity. The key amino acid site for determining O-type foot and mouth disease virus acid-resistant characteristics can be used for reconstruction of acid resistance of a foot and mouth disease virus vaccine and for exploitation of a novel foot and mouth disease gene engineering vaccine. The acid-resistant mutant strain rN17D can be used as a high-quality inactivated vaccine-production parent strain, can improve content of a 146S effective antigen in the inactivated vaccine and can improve vaccine immune efficacy.

Description

technical field [0001] The invention relates to an acid-resistant mutant strain of foot-and-mouth disease virus and the capsid protein and coding gene carried by it, in particular to an infectious cDNA plasmid clone of an acid-resistant mutant strain of an O-type foot-and-mouth disease virus and rescue of the infectious cDNA plasmid clone of an acid-resistant mutant strain of an O-type foot-and-mouth disease virus The acid-resistant mutant strain of O-type foot-and-mouth disease virus, and the invention also relates to the VP1N17D mutation site and application for determining the acid-resistant property of the O-type foot-and-mouth disease virus acid-resistant strain, belonging to the field of foot-and-mouth disease virus prevention and control. Background technique [0002] Foot-and-mouth disease (Foot and Mouth Disease, FMD) is caused by Foot and Mouth Disease Virus (Foot and Mouth Disease Virus, FMDV), an acute, febrile, highly contagious infectious disease that mainly aff...

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Problems solved by technology

However, because FMDV is extremely sensitive to an acidic environment, when FMDV is propagated in vitro, acid production by cell metabolism can easily reduce the pH of the FMDV culture environment. When the pH value is slightly lower than neutral conditions, the capsid of FMDV will be cleaved, resulting in The effective antigenicity of FMDV is reduced, and the immune efficacy of the inactivated vaccine thus prepared will decrease (Doel, T.R., and W.K.Chong.1982.Comparativeimmunogenicityof146S,75Sand12Sparticlesoffoot-and-mouthdiseasevirus.ArchVirol73:185-191.)

In addition, FMDV capsids are also sensitive to temperature, which requires a complete cold chain system during the transportation and storage of FMDV inactivated vaccines, resulting in a substantial increase in costs

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