Preparation and immunogenicity of influenza vaccine lyophilized liposomes

Aim ：To prepare the influenza vaccine lyophilized liposomes and to characterize its particle distribution，encapsulation efficiency and immunogenicity. Methods ：Flu vaccine liposome based on the method of thin-film evaporation was prepared using phospholipids ，cholesterol and the purified influenza virus split vaccine，and was further subjected to frozen-drying.The polymorph was observed by microscope；the particle distribution and the average size were analysed by transmission electron microscope；its encapsulation efficiency was determined by Lowry method and the antibody titers were assessed by hemagglutination-inhibition after pulmonary delivery to mice. Results ：The reconstitated influenza vaccine liposome under electronic microscope were round or elliptic particles evenly distributed at a mean size of 2.14 μm，with the encapsulation efficiency of more than 80%.The antibody titer through pulmonary delivery was higher than that through intraperitoneal injection. Conclusion ：The prepared influenza vaccine lyophilized liposomes possess high encapsulation efficiency，better particle distribution and marked immunogenicity through pulmonary delivery to mice.Pulmonary delivery of influenza vaccine liposomes is a potential immunization approach worthy of further exploitation.