A new cell line from the fat body of Spodoptera litura (Lepidoptera, Noctuidae) and detection of lysozyme activity release upon immune stimulation

A new cell line, designated NIAS-SL64, was established from the fat body of the fifth instar larvae of the common cutworm Spodoptera litura. NIAS-SL64 cells grew as spindle-shaped and non-adherent cells in the insect-specific cell culture medium MGM-450 supplemented with 10% fetal bovine serum. Criterions for the establishment of the NIAS-SL64 cell line is spindle shape and length (30~90 μm) stabilized after 100 passages. The doubling time of the cells was 24 h at 25°C. Lipopolysaccharide significantly stimulated the release of lysozyme activity by NIAS-SL64 cells. Lysozyme is one of the components of the innate immunity and plays important role as lytic enzyme in infection. Lysozyme activity released from NIAS-SL64 would be a marker for immune response. The released lysozyme activity critically depends on morphology of the cells and would be a criterion of the establishment of the cell line. Lysozyme activity was suppressed in a dose-dependent manner by the immunosuppressive agent cyclosporin A.