42 results about "Pathogenic avian influenza" patented technology

The invention discloses a highly pathogenic H7N9 avian influenza virus antigen with low receptor binding activity and a preparation method thereof, comprising the following steps: preparing a mutant HA gene; preparing the full-length highly pathogenic H7N9 avian influenza virus after mutation The gene sequence of the HA protein is to obtain the R220G mutant HA gene; wherein the R220G mutant HA gene sequence is shown in SEQ ID NO.2; virus rescue: the R220G mutant HA gene is used to rescue the recombinant influenza virus. In the recombinant highly pathogenic H7N9 avian influenza virus prepared by the method, the arginine at position 220 in the receptor binding region is mutated into glycine to reduce the binding affinity of the HA protein receptor.

The invention discloses a highly pathogenic H7N9 avian influenza virus antigen with low receptor binding activity and a preparation method thereof, comprising the following steps: preparing a mutant HA gene; preparing the full-length highly pathogenic H7N9 avian influenza virus after mutation The gene sequence of the HA protein is to obtain the R229I mutant HA gene; wherein the R229I mutant HA gene sequence is shown in SEQ ID NO.2; virus rescue: the R229I mutant HA gene is used to rescue the recombinant influenza virus. In the recombinant highly pathogenic H7N9 avian influenza virus prepared by the method, the arginine at position 229 in the receptor binding region is mutated into isoleucine to reduce the receptor binding affinity of the HA protein.

The invention discloses construction and application of a recombinant turkey herpesvirus expressing H7N9 subtype highly pathogenic avian influenza virus HA protein. The recombinant turkey herpesvirusis obtained by inserting an exogenous gene expression box between the HVT-065 and HVT-066 genes in a non-essential replication area of a coding sequence of a turkey herpesvirus (HVT), wherein the exogenous gene expression box is formed by connecting an MCMV promoter, an exogenous gene and SV40 poly A in sequence; the exogenous gene is the H7HA gene, and the nucleotide sequence of the exogenous gene is shown as SEQ ID NO:1. The construction method of the recombinant turkey herpesvirus is also provided. An ultrasonic cracking and breaking method is adopted for purification, the screening time isshortened, and the obtained recombinant turkey herpesvirus rHVT-H7HA provides good protection for the highly pathogenic H7N9 subtype avian influenza virus and can be used for subsequent development of new avian influenza virus vaccines.

The invention discloses a highly-pathogenic avian influenza virus hemagglutinin protein identification method, which can be used for highly-pathogenic avian influenza virus hemagglutinin protein identification and provide a reference for understanding the structural characteristics of the highly-pathogenic avian influenza virus hemagglutinin protein; through the identification of the hemagglutininprotein, the method can indirectly distinguish the degree of the pathogenicity of the avian influenza virus strain to which the hemagglutinin protein belongs. The method comprises the following steps: a), to establish an amino acid holographic topological structure score vector, based on principal component analysis; b), to apply the amino acid holographic topological structure score vector to characterize the structure of the influenza virus hemagglutinin protein; c), to carry out normalized processing to the characteristic variable of each influenza virus hemagglutinin protein through a self-cross-covariance method; d), to establish an avian influenza virus hemagglutinin protein identification model through an RBF kernel-based support vector machine; e), to establish a highly-pathogenicavian influenza virus hemagglutinin protein identification model through the RBF kernel-based support vector machine.

The invention discloses a preparation method of a highly pathogenic H7N9 avian influenza virus, which can improve the immunogenicity of the virus, comprising the following steps: preparing a Q226L mutant HA gene, and preparing a highly pathogenic H7N9 avian influenza virus with a Q226L mutation The gene sequence of the full-length HA protein is obtained to obtain the Q226L mutant HA gene; the virus is rescued, and the recombinant influenza virus is rescued by using the Q226L mutant HA gene. The invention also discloses the highly pathogenic H7N9 avian influenza virus prepared by the method, the vaccine prepared by using the highly pathogenic H7N9 avian influenza virus and its preparation method, and the detection method prepared by using the highly pathogenic H7N9 avian influenza virus reagent. The preparation method of the highly pathogenic H7N9 avian influenza virus of the invention improves the biological safety and immunogenicity of the recombinant virus.

The invention relates to a method for identifying the influence of concurrent bacterial infection on the pathogenicity of avian influenza virus infection and a device used therefor. Co-inoculate bacteria that secrete subtilisin-like protease or / and bacteria that secrete tryptase and low-pathogenic avian influenza virus in the CEF culture, so that the bacteria cannot directly contact CPE but the enzymes they secrete can enter the culture medium, continue Cultivate and observe the presence or absence of CPE; according to the appearance of CPE, the cause of a large number of chicken deaths can be identified. The cell in vitro homogeneous culture device used in the method is composed of a cell culture bottle and a bacteria culture room, and the bacteria culture room is a closed structure with a microporous filter membrane with a pore size not greater than 0.22 microns that can communicate with the cell culture bottle. The method of the invention is simple and easy to operate, the identification time is short, the result is accurate and reliable, and the device used is low in price, and has important significance for the detection and prevention of bird flu.