Abstract: We have synthesized a novel formulation of nanoparticulate(NP) alum adjuvant specifically in the cationic water-in-oil microemulsions of water/benzalkonium bromide(BB), octyl alcohol/cyclohexane at 30 ℃, which was characterized to be crystalline Al(OH)₃ with average particle diameter about 70 nm by the analysis of X-ray diffraction and to have a spherical shape structure by TEM photography analysis. Then adsorption degree was assayed. The OD₄₉₂ of the NP is about 10 times higher than the bulk(BK) alum adjuvant. Compared to bulk alum adjuvant, we studied the immune effect of the NP alum adjuvant with HBsAg vaccine, which was injected intraperitoneally into Guinea pig, and serum antibody titers of the first and second week after immunization were higher in NP group than BK group by ELISA(P<0.01, P<0.05); Groin immuno-injection intraperitoneally into Balb/c mice, was performed once or there times, prolife responses of spleen cells were determined by ³H thymidine incorporation; non-specific phagocytosis of macrophage of abdominal cavity was measured by lack of color Malachite Green and IL-2 was assayed by activation mouse spleen cells. It is indicated that all cellular immunity bioassay results were higher in NP group than in BK group, except non-specific phagocytosis of macrophage of abdominal cavity by there times immunity. However, there was no significant differerces. Thus, nanoparticulate alum adjuvant can be employed as a more effective adjuvant for HBsAg vaccine than bulk alum adjuvant in the earlier period of post-immunity.

Key words: Microemulsion, Nanoparticulate alum adjuvant, Hepatitis B surface antigen, Humoral Immunity, Cellular immunity