Available technological options Egg-based process Infection with seed virus Splitting,inactivation and purification Cell culture process Infection with seed virus Splitting,inactivation and purification Transient expression of Haemagglutinin Establish Vector Purification of transient intracellular or ex pression secreted protein System (e.g. GE imoginB0地irus) GEritk ar 2r/ 11/2/2四/