Culture previously prepared Spodoptera frugiperda, or Sf9 cells, in suspension in spinner flasks by continuously stirring at 130 rpm on a multipoint stir plate system. Maintain culture volumes at no more than half the volume of the spinner flask for proper aeration. Next, express CHIK VLPs by infecting 250 milliliters of Sf9 cells in a spinner flask at a density of 2 x 106 cells per milliliter with previously prepared recombinant baculovirus, and return the cells to a 28-degree Celsius incubator.
Use trypan blue exclusion to determine if the cell viability has decreased to 70% to 80%. Upon confirmation, transfer the cultures directly from suspension into 50-milliliter conical tubes, and spin the cells down. Collect the supernatants, and filter them through a 0.22-micron pore membrane before sedimentation.
