Establishment And Characterizaton Of A New Cell Line From Embryos Of Trichoplusia Ni

A suspended cell line,QB-Tn-9-4s,from Trichoplusia ni embryos was established, and the susceptibility to Autographa californica multiple nuclear polyhedrosis virus (AcMNPV)infection was investigated.This cell line had characteristics distinct from homogenous BTI-Tn5B1-4 cell line from T.ni in growth,and showed approximately the same responses to AcMNPV infection,production of occlusion bodies,and levels of recombinant protein expression.But no clumps were observed when maximum density at late-log phase in shake-flask or T-flask cultures,and thus the cells represent an useful new contribution for baculovirus research because of fairly well dispersal.The cells consist of two major morphological types:spindle-shaped cells of 70%and round cells of approximately 30%.The cell line was highly susceptible to virus infection and produced around 107 AcMNPV occlusion bodies per cell,on average.By random amplified DNA-polymerase chain reaction test,using primers OPU-09, OPU-10,N0.2,T.ni identification,cell lines QB-Tn9-4s with the genome DNA profiling Trichoplusia ni eggs genomic DNA,Tn5B1-4 cells genomic DNA bands consistent with Sf-9 genome DNA of the cell with distinctly different that QB-Tn9-4s cell line is derived from an Trichoplusia ni cell lines,and the preservation of the laboratory cells and other cells are not cross polluted.QB-Tn9-4s is highly a recombinant protein expression of the insect cell lines.With recombinant virus AcMNPV-β-gal infecting cells,QB-Tn9-4s cellsβ-galactosidase enzyme production and Tn5B1-4 considerable,and far higher than Sf-9,the eighth day to achieve the greatest expression of(2.53±0.034)×10~4IU/mL,that is 1.98 times of Sf-9. With the extension of time,QB-Tn9-4s medium-volume gradually increase,the eighth day QB-Tn9-4s cells and culture of the total concentration of the expression reaching(3.97±0.13)×10~4lU/mL.AcMNPV-SEAP infects the cell,the cells secreted in the base of phosphatase expression levels are significantly lower than the medium of expression,only a maximum of 0.8 IU/mL.QB-Tn9-4s infecting the recombinant protein expression equals that of Tn5B1-4,the ninth day to achieve the greatest expression of(3.52±0.4)IU/mL,but always higher than Sf-9,moreover,the ninth day the number is 2.32 times of Sf-9.