Traditional Chinese Medicine (TCM) has been used to treat diseases in China for thousands of years. TCM compositions are complex, using as their various sources plants, animals, fungi, and minerals. Polysaccharides are one of the active and important ingredients of TCMs. Polysaccharides from TCMs exhibit a wide range of biological activities in terms of immunity-modifying, antiviral, anti-inflammatory, anti-oxidative, and anti-tumor properties. With their widespread biological activities, polysaccharides consistently attract scientist's interests, and the studies often concentrate on the extraction, purification, and biological activity of TCM polysaccharides. Currently, numerous studies have shown that the modification of polysaccharides can heighten or change the biological activities, which is a new angle of polysaccharide research. This review highlights the current knowledge of TCM polysaccharides, including their extraction, purification, modification, and biological activity, which will hopefully provide profound insights facilitating further research and development.
Nanoparticle-based vaccine delivery
systems have been extensively
used to promote and induce immune responses to protein antigens. The
properties of the nanoparticles, such as size, surface charge, and
antigen loading mode, have been proved to significantly influence
the adjuvant effect and immunoreactivity of nanoparticle-based vaccine
delivery systems. The purpose of the study was to investigate how
the surface charge and antigen loading mode of nanoparticles impact
the immune responses. In this study, three ovalbumin (OVA)-loaded
poly(lactic-co-glycolic acid) (PLGA) nanoparticles
with different surface charges and antigen loading modes were developed.
The three nanoparticles were designed as antigen encapsulated with
negatively charged (Angelica sinensis polysaccharide (ASP)-PLGA/OVA),
antigen encapsulated with polyethylenimine (PEI)-coated (ASP-PLGA/OVA-PEI),
and antigen adsorbed on PEI-coated (ASP-PLGA-PEI-OVA) nanoparticles.
The Angelica sinensis polysaccharide (ASP) was used as the immunopotentiator
and encapsulated into three nanoparticles. The results demonstrated
that both PEI-coated (positively charged) nanoparticles promoted the
antigen escape from the endosome, which led to the cytoplasmic antigen
delivery to generate cross presentation, compared to negatively charged
nanoparticles. In addition, PEI-coated nanoparticles activated the
DCs in lymph nodes 5 days after the primary vaccination. In vivo experiments
demonstrated that both antigen-encapsulated nanoparticles induced
more potent and long-term antigen-specific antibody responses, compared
to that of antigen-adsorbed nanoparticles. Thus, the PEI-coated and
antigen-encapsulated nanoparticles (ASP-PLGA/OVA-PEI) as a vaccine
adjuvant delivery system have the potential to induce strong and long-term
humoral and cellular immune responses.
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