Fig. 6.

(a) HBsAg serum antibody assay in groups of BALB/c mice immunized either m-chitosan microspheres or naked DNA alone. The immunization protocol was performed at weeks 0, 2, 4 and 6. At the different time points of 5 and 7 weeks, HBsAg-specific antibody was measured in serum from each group of mice (as pools of five) (p < 0.05). OD450≥0.2 represents positive value. (b) Analysis of cytolytic activities of splenic mononuclear cells harvested from mice immunized. P815 mastocytoma cells pulsed with epitope peptides were used as targets. Percent specific lysis was determined by a 4-h LDH-release assay (p < 0.05). (c) The HBsAg-specific, IFN-γ producing splenocytes were generated in mice by HBsAg DNA vaccine after intramuscular injection. Each bar represents the average number of cells secreting IFN-γ per 10⁶ cells (p < 0.05).