title: Aggregation and antigenicity of virus like particle in salt solution--A case study with hepatitis B surface antigen.
abstract: The phenomenon of aggregation of virus-like particles (VLPs) in salt solution and the corresponding effect upon antigenicity was reported. Asymmetrical flow field-flow fractionation (AF4) combined with multi-angle laser light scattering (MALLS) was used to characterize the size and the aggregation behavior of hepatitis B surface antigen (HBsAg). The average diameter of HBsAg VLP was 22.8±0.4 nm and it tended to aggregate in salt solution to form large particles and the antigenicity changed accordingly. In 0-4 M NaCl solution, part of HBsAg molecules aggregated rapidly into oligomeric particles (OP), whose diameter distributed from 25 to 40 nm, and the antigenicity slightly decreased about 10%. The aggregation reaction is reversible. After removing NaCl, both size and antigenicity could recover to normal level (92-96%). By contrast, the aggregation process is more complicated in (NH4)2SO4 solution. Most of HBsAg particles aggregated into OP and further aggregated into polymeric particles (PP). The diameter of the PP could reach 40 to 140 nm. The concentration of (NH4)2SO4 had remarkable influence upon the rate of aggregation. When concentration of (NH4)2SO4 was below 1 M, most of HBsAg aggregated only into OP in 1 h. While with concentration of (NH4)2SO4 above 1 M, most of particles formed PP within 1 h. The aggregation process to PP was irreversible. After removing (NH4)2SO4, the large aggregates could not recover to normal particles and the remaining antigenicity was below 30%.
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China; Graduate University of Chinese Academy of Sciences, Beijing 100049, PR China.
authors: Yi
authors: Y
authors: Chen
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Yan
authors: Y
authors: Zhang
authors: Division of Chemistry, National Institute of Metrology, Beijing 100013, PR China.
authors: Can
authors: C
authors: Quan
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Jian
authors: J
authors: Luo
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Yanli
authors: Y
authors: Yang
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Mengran
authors: M
authors: Yu
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Yingjun
authors: Y
authors: Kong
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China.
authors: Guanghui
authors: G
authors: Ma
authors: National Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China. Electronic address: zgsu@ipe.ac.cn.
authors: Zhiguo
authors: Z
authors: Su
mesh_terms: D064751:Ammonium Compounds; D031521:Fractionation, Field Flow; D006514:Hepatitis B Surface Antigens / Q000737:chemistry* / Q000276:immunology* / Q000502:physiology; D046529:Microscopy, Electron, Transmission; D010316:Particle Size; D012965:Sodium Chloride
chemical_list: D064751:Ammonium Compounds; D006514:Hepatitis B Surface Antigens; D012965:Sodium Chloride
keywords: Aggregation; Antigenicity; Asymmetrical flow field-flow fractionation; Hepatitis B surface antigen; Virus-like particle