ABSTRACT
@#To investigate the cellular immunogenicity of influenza vaccine liposomes dry powder using the film-dispersion and freeze-thawing. Mice were divided into the non-liposomal influenza vaccine group, film-dispersion prepared liposomal influenza vaccine group, freeze-thawing lyophilized influenza vaccine liposome group, positive control group and negative control group(n=5). 6 μg of hemagglutinin of H1N1 subtype per mouse was delivered tracheally to the mice of lyophilized liposomes groups, with the same dose for non-liposomes intraperitoneally delivered groups as the positive control, and PBS intraperotoneal injection group as the negative control. After 28-day of immunization, the proliferationofsplenic lymphocytes was detected by MTT assay; CD4+cell and CD8+cell were analyzed by flow cytometry. The dry powder of influenza vaccine liposomes prepared by the above two methods, both induce cellular immunity, with no significant difference in the induced on immunogenicity between the prepared products(P< 0. 05). The results showed that freeze-thawing method is feasible in the preparation of vaccine liposomes, leading to the attenuated live vaccine liposome preparation.
ABSTRACT
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 祄, 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.