ABSTRACT
Newcastle disease virus-like particles (NDV VLPs) are composed of matrix protein (M) as the skeleton,with the insertion of hemagglutinin-neuraminidase and/or fusion protein.NDV VLPs are reported to be immunogenic and can induce specific humoral and cellular immune responses.However,its relationship with innate immunity remains elusive.Dendritic cells (DCs) are a group of specialized antigen presenting cells,which are crucial in connecting innate immunity and adaptive immunity.In this study,NDV VLPs and murine DCs were used to investigate the connection between NDV VLPs and innate immunity.The DC maturation induced by NDV VLPs (M+ HN) was evaluated.The results showed that NDV VLPs could be effectively taken up by DC and presented to naive T cells.NDV VLPs-induced DC significantly up-regulated the expression of MHC Ⅱ and costimulatory molecules on DC surface,and subsequently promoted the secretion of proinflammatory cytokines.This experiments also showed that different assembled NDV VLPs induced significant stimulating ability in cytokine levels.In summary,NDV VLPs can induce DC maturation,which gives insights to better understanding of VLPs-mediated innate immunity and provide information in selecting preferred NDV VLPs candidate.
ABSTRACT
Objective To compare the contents of astragaloside Ⅳ and polysaccharides in radix astragali with different growth years, providing reference for the better harvest time of radix astragali. Methods HPLC-ELSD was used to determine the content of astragaloside Ⅳ. A Hypersil-Keystone C18 column was used with the mobile phase consisting of acetonitrile-water (33∶67). The flow rate was set at 1.0 mL/min. The parameters of drift tube and gas flow rate of the detector were set at 105 ℃ and 2.7 L/min respectively. Phenol-sulfuric method was employed to determine the content of polysaccharides, and the detection wavelength was set at 490 nm. Results The linear range of astragaloside Ⅳ was within 1.25-6.28 μg. The average recovery was 97.28%, with RSD=1.42%. The linear range of polysaccharides was 10-100 μg. The average recovery was 99.02%, with RSD=0.94%. The content of astragaloside Ⅳ in radix astragali cultivated for more than 1 year was higher than the standard in Chinese Pharmacopoeia, and radix astragali cultivated for 3 years showed the highest content. The content of polysaccharides in radix astragali cultivated for more than 3 years was the highest, and radix astragali cultivated for 2 years was slightly lower. Conclusion The better harvest time for radix astragali is at least two years of growth, which is judged from the content of astragaloside Ⅳ and polysaccharides.