动物造模,HBV转基因小鼠模型 z-bio 2021-12-16 267

　　Establish transgenic mice expressing part or all of the HBV genome, and study the mechanism of HBV replication, the expression of viral genes in liver cell injury, and HBV immunopathology. It should be noted that transgenic mice with viral replication are usually resistant to viral antigens.

　　In 1985, we established the first transgenic mouse model for studying HBV infection. HBV is established by inserting the full length of the HBV genome carrying each virus gene (including large, medium, and small surface protein genes, X protein genes, core antigen genes, and pre-core antigen protein genes) into the mouse chromosomes. We have found that transgenic mice and virus surface and x antigens are related to the development of cancer. After inserting the gene encoding the surface antigen of the large virus into the mouse chromosome, a non-secretory surface antigen was synthesized on the endoplasmic reticulum membrane of the mouse liver. In mice in which all liver cells express surface antigens, severe liver damage occurred 2-3 months after birth, regenerative nodules appeared at 6 months after birth, and liver cancer appeared at 15 months after birth. Will have

　　After the HBV genome of the X gene was inserted into the chromosome of ICR mice, these mice developed liver tumors when they were 8-10 months old. The life span of transgenic mice (11-15 months) is shorter than that of wild mice (17-21 months). The autopsy report showed that 80% to 91% of males and 60% to 67% of female transgenic mice contained one or more liver tumors.

　　In 1995, American scholars established a transgenic mouse model carrying 1.3 times the HBV genome. The liver cells of such transgenic mice can synthesize high levels of virus particles, and the virus level corresponds to the virus concentration of the infected HBV in the liver. Unfortunately, yes, the mouse liver does not have any pathological changes. In addition, high levels of viral gene expression can also be detected in the kidneys of transgenic mice. Among them, the viral mRNA content in the central part of the liver lobules is higher than that in other parts of the liver lobules. This model can be used to study host factors that affect virus replication, and to evaluate vaccines and drugs. The entire genome of HBV was injected into the fertilized eggs of C57 mice to produce transgenic mice with the HBV genome. HBV replication and viral DNA transcripts were detected in the liver, kidney, and heart of the transgenic mice, the size of which was similar to that produced in a natural infection state. The core antigen of the virus was observed in the nucleus of liver cells by immunohistochemistry. The replication rate of the virus in transgenic mice is lower than that of humans. However, this model did not report mouse viremia, could not be purified to complete virus particles, and could not explain the pathological changes in the liver. Glucocorticoids and androgens can up-regulate viral expression in transgenic mice. So far, people have used transgenic mouse models to obtain a lot of valuable information, which relates to the immune system response during HBV infection and the CTL effect mediated by type I MHC. In the above study, the transfer of CD8+, HBsAg-specific MHC type I cytotoxic T lymphocytes to transgenic mice may induce acute hepatitis and accompanied by liver cell damage. After CTL binds to HBsAg-positive stem cells, the IL-7 secreted by them can activate liver macrophages and may cause liver damage in mice. However, CTL can also eliminate the virus by releasing cytokines without lysing the cells. This reduces the level of viral RNA in liver cells where the virus is actively replicating. Recently, it was discovered that injection of HBC-specific CTL into the liver of HBV transgenic mice can mobilize non-antigen-specific inflammatory cells into the liver, a process that exacerbates the severity of liver damage. At the same time, knocking out Gr-1(+) neutrophils can reduce liver disease induced by CTL. In addition, inhibiting MMP (matrix metalloproteinase) synthesized by Gr-1(+) cells can reduce liver damage without reducing the antiviral activity of antigen-specific CTL. HBV transgenic mice are immune to viral antigens, so transgenic mice will not show chronic liver damage. In order to destroy the resistance of mice to HBV antigens, the researchers constructed SCID transgenic mice carrying replicated all-round HBV genomes. Such mice can exhibit sustained gene expression and virus replication in the liver and serum for life. After the allogeneic spleen cells were transferred to mice, the virus in the liver and serum of the mice was basically eliminated, and then chronic liver disease was developed. In addition, injection of a large number of splenocytes into transgenic mice can induce acute self-limiting hepatitis.