Adjuvants are important for vaccines to reduce the amount of antigen used and improve the immune response ability of antigens. However existence of adjuvants may sometimes alter the antigen structures and subsequently affect their immunogenicity. The effect of aluminum hydroxide adjuvant on the structure of recombinant hepatitis B core antigen (HBcAg) was studied. Differential scanning fluorimetry (DSF) showed that the melting temperature (Tm) of HBcAg was significantly decreased for 5.4 ℃ by adsorbing to aluminum hydroxide adjuvant, indicating adjuvant will reduce the thermal stability of HBcAg. The adsorbed HBcAg on aluminum hydroxide adjuvant was released with 1 M NaCl and was analyzed by high performance size exclusion chromatography (HPSEC). HPSEC showed the antigens partially aggregated and dissociated. Transmission electron microscopy (TEM) further showed that the adsorbed HBcAg became ellipse, suggesting some distortion occurred. Furthermore, the effect of storage temperature for adjuvanted HBcAg was evaluated at -20 °C, 4 °C, and 37 °C. The Tm was all decreased as compared to free antigen. The Tm of 89.0 °C was the highest at 4 °C, indicating the HBcAg was the most stable under this storage condition. The study indicated adsorption of HBcAg to aluminum hydroxide adjuvant will cause some structural changes and reduce its thermal stability. Therefore the influence of adjuvant on antigen cannot be ignored in formulation research.

Zheheng Liang. Effect of Aluminum Adjuvant on the Structure of Recombinant Hepatitis B Core Antigen. The Frontiers of Society, Science and Technology (2020) Vol. 2 Issue 13: 27-38. https://doi.org/10.25236/FSST.2020.021304.

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