ABSTRACT
This study aimed to analyze the proliferation characteristics of porcine deltacoronavirus (PDCoV) in suspension cultured porcine kidney cells LLC-PK1, so as to provide Candidate cell for large-scale production of PDCoV inactivated vaccine. LLC-PK1 cells were suspended by gradually decreasing serum method. PDCoV adaptive monoclonal cell lines were screened by limited dilution method. Indirect immunofluorescence method was used to identify the infectivity of PDCoV. The initial cell density, MOI, time of receiving virus collection and TPCK pancreatin concentration were screened to determine the best suspension culture conditions. The suspension cell strain LLC-PK1Sa which can proliferate PDCoV efficiently was screened out;PDCoV can specifically infect LLC-PK1 cells;PDCoV inoculated LLC-PK1Sa cells with a density of 2 x 106 cells.mL-1 according to the MOI of 10-3, When the final concentration of TPCK pancreatin reached 7.5 g.mL-1, the titer of virus solution harvested 48 h after inoculation was the highest. In this study, the efficient proliferation of PDCoV in LLC-PK1Sa suspension cells was realized for the first time, and the suspension culture conditions were preliminarily optimized, which could provide theoretical reference for large-scale production of PDCoV inactivated vaccine.