Establishment and characterization of an ovarian cell line of the silkworm, Bombyx mori

A cell line BmN-SWU1 was established from the ovarian tissues of 3-day-old fourth instar Bombyx mori larvae of the 21-872nlw variety by performing primary cultures in Grace's medium supplemented with 20% fetal bovine serum (FBS). The cell line primarily consisted of short spindle cells and round cells. The frequency of cells with chromosome number 2n = 56 was 80.5%; therefore, the cell line was considered to be a diploid cell line. The population-doubling time (PDT) at 45th passage line was 57.7 h. This cell line was susceptible to the B. mori nuclear polyhedrovirus (BmNPV), and the median tissue culture infective dose (TCID50) at a cell density of 105 cells/ml was 16.3 OBs/ml. The transient expression efficiency of the green fluorescent protein (GFP) gene in this cell line was 54.8%. We used the BmN-SWU1 cell line to select and establish a GFP transgenic cell line.