| Lymphocystis disease is a chronic diseases in many kinds of fish,which is caused by viral infection of lymphocystis disease virus, a typical disease adhere to fish skin and epidermal tissue. Lymphocystis disease's wide range of epidemic has aroused great attention from scholars at home and abroad. At present, there are at least 42 families known, more than 125 kinds of fish can be infected by this disease, Currently, the pathogens, clinical symptoms, pathological changes and diagnosis of Lymphocystis disease have been reported from several aspects. However, the molecular mechanism of pathogenesis is not clear , and there are no great breakthroughs in area of vaccine research. Therefore, to control and overcome the disease, it is still needed to pay a great deal of effort. In this experiment,we further explore and optimize the conditions of flounder gill cells infected with LCDV,obtaining infectious characteristics of the situation under the different conditions of infected cells. Then the mathematical model associated with the impact factors of the infection (multiplicity of infection, culture time post infection and cultivation temperature) is constructed based on the mathematical linear regression analysis.Respectively, inoculated in a MOI of 5 TCID50/cell, 10TCID50/cell,15TCID50/cell,20 TCID50/cell,30 TCID50/cell and 35 TCID50/cell,adjusted the temperature of cultivation condition to 16℃,18℃,20℃,22℃,24℃,26℃and 28℃,tested the vitality of cell metabolism at the days of 1d, 2d, 3d, 4d, 5d, 6d and 7d for observation of cytopathic effect. In this paper, under the conditions of different MOI(multiplicity of infection), culture time post infection and cultivation temperature , the effect of metabolic activity of cells infected by LCDV (lymphocystis disease virus) is studied, including the relationships between the above three factors in the virus infection and reduction of cell metabolic activity. The experimental results show that the cytopathic effect is consistent with the decline of cell metabolic activity, virus-induced cytopathic effect are positively correlated with the MOI(multiplicity of infection), culture time post infection and cultivation temperature, in which MOI(multiplicity of infection) influences metabolic activity of cells the most significantly, followed by incubation time and temperature affect the lightest. The results showed that: at the early infection stage,virus infection to stimulate cell metabolic activity and proliferation,then infectious cells display a decline in the metabolic activity and cell death. The CPE was positively associated with MOI,h.p.i and post-culture time and the correlation coefficients wereα,βandγ. Use mathematical regression analysis to build an induced cytopathic effect model by the virus infection.In this study,based on the impact of CPE according to the three variables and the two linear regression mode(lf(X1)= -1.3786x+102.00;f(X2)= -1.089x+96.11), and a complicated model constituted of one linear regression model and one index model( f(X2)= 17x+101.50,f(X2)= 222.9e-0.6153x+1.051e0.3282x ) constructing the difference model with three values by applying the Matlab software, describes the interaction between virus and host cell and analyzes each single variable (X1,X2,X3) of metabolic activity of flounder gill cells infected by LCDV. The correlation coefficient areα,βandγ,valued respectively -1.3786,-1.15 and -1.089,representing the extent of metabolic activity casued by different MOI(multiplicity of infection), culture time post infection and cultivation temperature. The model accurately describes the relationship between the degree of infectious cells and impact factors,providing guidance for the establishment of suitable in vitro infection system for interaction between virus and host.
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