The Effect Of Three Kinds Of Adjuvants On A H5N1Influenza DNA Vaccine

Since first discovered in1878, Avian influenza has made large number of casualties and huge economic losses. At present, the prevention of avian influenza mainly rely on influenza vaccines. Commonly used human influenza vaccines are inactivated vaccines. DNA vaccines as a novel vaccine are considered the best approach to cope with avian influenza virus but have the disadvantage of low immunizing potency. As nonspecific immunostimulants, the immune adjuvants play an important role in the research and application to improve vaccine efficacy. Several kinds of novel adjuvants may be used with human vaccines in future, include cytokines, immunomodulator, etc. Especially, DNA vaccines can be designed to co-express so called’genetic adjuvant’molecules like cytokines or co-stimulatory molecules. Studies have shown that the appropriate use of adjuvants can greatly enhance the immune effect of avian influenza DNA vaccines.In this study, the eukaryotic expression vector pcDNA3.1(+)-CD40have been constructed, polysaccharide nucleic acid fraction of bacillus Calmette-Guerin, thymopentin have been prepared.6-8weeks old BALB/c mice were immunized by DNA vaccine pcDNA3.1(+)-HA with these three kinds of adjuvants. Mice in seven control groups were administrated with nothing, pcDNA3.1(+) plasmids, pcDNA3.1(+)-HA with pcDNA3.1(+) plasmids, pcDNA3.1(+)-CD40with pcDNA3.1(+) plasmids, pcDNA3.1(+) plasmids, thymopentinas, polysaccharide nucleic acid fraction of bacillus Calmette-Guerin. All mice were immunized once every two weeks, a total of three immunizations. Enzyme-linked immunosorbent experiment was performed to detect HA antibody of serum to evaluate the level of humoral immunity.The results show that pcDNA3.1(+)-CD40enhence the humoral immune response; thymopentinas reduce the humoral immune response; polysaccharide nucleic acid fraction of bacillus Calmette-Guerin have no effect on the humoral immune response.