Nanostructured SBA-15 silica as an adjuvant in immunizations with hepatitis B vaccine
To evaluate the applicability of SBA-15 silica as an adjuvant in immunizations with purified particles of the viral protein HBsAg, the main component of hepatitis B vaccine, Butang®, produced by Instituto Butantan.
BALB/c mice orally or subcutaneously received 0.5 μg of HBsAg adsorbed/encapsulated to SBA-15 or adsorbed to Al(OH)3. To assess the secondary immune response, a subcutaneous booster was administered 30 days after the first immunization. Individual serum and fecal samples of each group were periodically collected for specific antibody titration by ELISA.
Analysis of secretory IgA showed that mice orally primed with HBsAg on SBA-15 had increased levels of specific antibodies in primary and secondary immune responses. Specific serum IgA and IgG titers in HBsAg:SBA-15-orally immunized mice reached higher levels after the booster, demonstrating the effectiveness of oral vaccination with the use of silica. All immunized groups showed higher IgG1 levels.
Our results clearly indicate the promising use of SBA-15 as an adjuvant, especially in oral immunizations.