Physicochemical and immunological characterization of two forms of recombinant norovirus GⅡ.4 virus-like particles assembled in Hansenula polymorpha / 中华微生物学和免疫学杂志

ABSTRACT

Objective To investigate the physicochemical properties and immunogenicity of virus like particles(VLPs) in two different conformations assembled from the essential capsid protein VP1 of GⅡ.4 norovirus(NoV) in Hansenula polymorpha. Methods NoV GⅡ.4 VLPs in two different conforma-tions were prepared from high-density fermentation of recombinant engineered strains and VLPs purification. Physicochemical properties of the two forms of VLPs were identified by Western blot,size-exclusion high per-formance liquid chromatography (SEC-HPLC), dynamic light scattering(DLS) and transmission electron microscopy. Serum VLPs binding activities and blocking activities against VLPs binding to histo-blood group antigen(HBGA-VLPs) were evaluated after immunization of BALB/c mice with the two forms of VLPs. Re-sults VLPs of two different diameters with high homogeneity were obtained after purification. DLS results showed that particle sizes of two VLPs were 53.98 nm and 45.18 nm,respectively. The two VLPs were sim-ilar in binding abilities to HBGA receptors. Serum VLPs binding activities and blocking activities against HBGA-VLPs were found higher in NoV-VLP-L than NoV-VLP-S,but the difference was not statistically sig-nificant (P>0.05). Conclusion VLPs in two different conformations were obtained by expressing NoV GⅡ.4 VP1 proteins in Hansenula polymorpha. Though they were similar in physicochemical properties and immunogenicity,the NoV-VLP-L might be potential antigen candidates for the development of recombinant human norovirus vaccine.