| This research studies on the preparation technology and physicochemical properties of lipospme-DNA and chitosan-DNA of IBV, then immunized 7-day-old healthy chicken with IB DNA vaccines of liposome/DNA, chitosan/DNA, and liposome/(pDNAIL-2+DNA) complexes,with bare IB DNA vaccine as the control, Fluorescence Activated Cell Sorter (FACS) and indirect ELISA assays were employed to evaluate cell and humoral immunity.Immunized chicken were challenged with homoeotypic IBV and monitored for survival.The result of orthogonal test on liposome/DNA showed that uniform liposome/DNA suspension was made under the conditions of PC/Choi molar ratio of 5/4,40mg lipid per emulsionized water(ml),SA/PC molar ratio of 1/5, organic/inorganic phase volume ratio of 2/1,lipid/plasmid DNA quality ratio of 20/1. The preparation technology of chitosan/DNA complex was 0.4% chitosan solution incorporated with plasmid DNA with quality ratio of 10:1.Chicken were immunized with various DNA vaccines by intramuscular injection, FACS was used to detect the number of CD4~+ and CD8~+ T lymphocytes, and indirect ELISA methods were employed to detect special anti-IBV serum IgG The results showed that, in contrast with the control group, the number of CD4~+T lymphocyte 5 days after vaccination and CD8~+T lymphocyte of the experiment group 15 or 29 days after vaccination was significantly higher (P<0.05 or P<0.01); The titers of specific IgG of the experiment group were higher than that of the control group, but quietly. Moreover, during the experiment group, the number of CD4~+T lymphocyte of liposome/DNA vaccine induced was higher than that of pDNAIL-2/DNA(P<0.05or P<0.01), similarity liposome/ pDNAIL-2/DNA vaccine was higher than pDNAIL-2/DNA and chitosan/DNA vaccines(P <0.05). As to the titers of specific IgG, only liposome /pDNAIL-2 /DNA vaccine was higher than pDNAIL-2/DNA vaccine(P<0.05) 10 days after immunization, but it was no notable difference during other experiment groups. For the power of withstand a lethal...
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