【Animal modeling】-Tissue distribution of egg reduction syndrome virus in different strains of mice

  OBJECTIVE: To observe the proliferation and dynamic changes of the virus in different strains of mice by artificial infection with egg reduction syndrome virus, and to provide theoretical basis and data support for the construction of EDSV vectors.

  METHODS: BALB/c mice with normal immune system, T cell immunodeficiency nude mice (Nu) and highly immunodeficient mice (NSG) were selected as the research objects, 32 mice per strain, female, 5-6 weeks old, intraperitoneally EDSV was injected artificially, and serum was collected at 1, 3, 5, 7, 14, 21, 28, and 35 days after the challenge, and the indirect ELISA method was used for antibody monitoring; Rats were collected from 10 tissues of heart, lung, liver, spleen, kidney, small intestine, uterus, trachea, esophagus, and brain, and the relative quantitative comparative Ct method (△△CT) was used to detect the viral load in each tissue.

  Results: The expression of antibody in BALB/c mice could be detected in the serum 3 days after the challenge, and the antibody level reached the highest level at 14 days and maintained until 35 days after the monitoring period; Nu mice could also be detected at 3 days after the challenge. Compared with BALB/c mice, the expression level of antibody was lower than that of BALB/c mice. After 14 days of challenge, the level of antibody in the serum of Nu mice decreased, and the antibody remained at a low level until 35 days. The relative quantification results of nucleic acid showed that 1 day after infection of BALB/c mice, the virus expression level in liver tissue was the highest, reaching 5.45 orders of magnitude, followed by spleen, esophagus, uterus, small intestine, and then from high to low. The virus content in lung, trachea, kidney, heart, and brain tissue was the lowest. With the prolongation of infection time, the virus expression in each tissue decreased compared with the first day of infection. At 28 days after challenge, the virus expression in liver and spleen remained unchanged. Nu mice and NSG mice showed the highest virus expression in the spleen on the 1st day of infection, which was 3.95 and 4.05 orders of magnitude, respectively, followed by the liver, and on the 28th day of the challenge, the two kinds of mice could still be detected in various organs. A positive signal was obtained, and the expression of the virus in the liver and spleen was higher.

  Conclusion: EDSV can stimulate the immune response in mice, and the expression level of antibody in immunodeficient mice is low. The virus has liver, spleen and other tissue tropism in mice, and it has been developed as a vector for EDSV and used in experimental animal models. Reference data are provided for further research and applications.