The Growth Dynamics of HRSV in Human Diploid Cells

Objective To study the growth dynamics of the human respiratory syncytial virus (HRSV) in human diploid cells (KMB1)7,to find conditions for the large proliferation of the virus in vitro cells.Methods The A2 strain of HRSV was inoculated into human diploid KMB17 cells.Virus titer at different times was detected by microassay of cytopathic effect, and the growth curves were drawn. At the same time, cells were infected by different multiplicity of infection (MOI).The time that the first cell and all the inoculated cells lesioned was observed,and the infectious titer of the virus was detected to determine the optimal MOI.Results The results showed that the cell lesion began to appear after virus infected KMB17 cells 2 ～4 days later.Virus grew in logarithm levels 5～10 days later,the peak of virus proliferation was 10～11 days.The more dose MOI used,the earlier the cell lesions appeared. Cell began lesion after virus was inoculated 2～3 days later,and the cytopathic rate of three groups were 100% 6 days later.The infection titer was 7.37～7.50 lg CCID50/mL,no significant differences existed among the three groups.When the MOI was 0.1, 0.01 and 0.001, about 30% cell were injured 4 days later.All cells were injured 8～9 days later.The infectious titer was 6.50～7.00 lg CCID50/mL. When the inoculated dose was less than 0.0001 MOI,the cells injury was found when the virus was inoculated to cells 5 ～6 days later.Part of cells were still normal 14 days later, and the titer was only 6.00 ～6.12 lg CCID50/mL.Conclusion The A2 strain of HRSV can grow well in KMB17 cells.The peak of virus proliferation was 10～11 days,and the most optimal MOI was 0.1～1.0.