Synergistic effect of dual targeting vaccine adjuvant with aminated ß-glucan and CpG-oligodeoxynucleotides for both humoral and cellular immune responses.

Presently, clinically approved adjuvants (such as aluminum salts) fail to induce cellular immune responses, which is crucial to defend against intracellular pathogens (including HIV, malaria, tuberculosis and Ebola) and cancer. However, Freund's complete adjuvant potently stimulates both humoral and cellular immune responses, accompanying by high toxicity and severe side reactions. Here in this work, a CpG-oligodeoxynucleotides (CpG-OND) crosslinked aminated ß-glucan-Ovalbumin dual targeting nanoparticle (CpG-OND-AG-OVA) is prepared through a simple and mild ionic complexation method. The aminated ß-glucan plays dual roles as antigen presenting cells (APCs) targeted carrier and immunopotentiator (targeting and activating dectin-1 on APCs). Meanwhile, CpG-OND also plays dual roles as ionic crosslinker and immunopotentiator (targeting and activating Toll-like receptor 9 in APCs). The adjuvant activity of the particles is evaluated through in vitro and in vivo experiments. The particles significantly enhance uptake and sustained proteolytic processing of antigens, and result in APCs maturation, inducing robust Th1 and Th2-type immune responses comparable to Freund's adjuvant without obvious toxicity. The potent adjuvant activity of the nanoparticles may originate from dual targeting synergistic effects between aminated ß-glucan and CpG-OND. Accordingly, the dual targeting nanoparticles may be a promising vaccine adjuvant for inducing robust humoral and cellular immune responses against infectious diseases and cancers. STATEMENT OF SIGNIFICANCE: An ideal adjuvant for subunit vaccine should act as both a carrier to enhance the uptake, sustained processing and cytosolic delivery of antigens, and an immunopotentiator to stimulate antigen presenting cells (APCs) for activation of naive T cells. Additionally, it should be easy to obtain and safe with negligible toxicity. Unfortunately, both synthetic and natural polymers that have been developed into antigen delivery system cannot completely fulfill the requirements. In the present study, the authors design nanoparticles with aminated ß-glucan and CpG-oligodeoxynucleotides (CpG-OND) through a simple and mild method. ß-Glucan (a dectin-1 and TLR2 targeted PAMP) and CpG-OND (a TLR9 targeted PAMP) are readily accessible. Aminated ß-glucan plays dual roles in the nanoparticle as APCs targeted carrier and immunopotentiator. Meanwhile, CpG-OND also plays dual roles as crosslinker and APCs targeted immunopotentiator. By making use of synergistic effect of the dual targeting vaccine adjuvant with aminated ß-glucan and CpG-OND, the nanoparticles induce robust antigen specific immune responses comparable to Freund's adjuvant without obvious toxicity.

Antigen uptake and immunoadjuvant activity of pathogen-mimetic hollow silica particles conjugated with ß-glucan.

The aim of vaccines is to imitate the immune responses induced by pathogen infection without causing disease. Therefore, strategies of designing vaccine delivery systems by mimicking key features of pathogens are often used. For this purpose, the present study prepares pathogen-mimicking ß-glucan-conjugated hollow silica particles by using polystyrene or bacteria particles as templates. The particles perfectly duplicate the structure and morphology of pathogens and possess excellent properties of hollow silica particles, including large opening pore channels, large interior cavities, high loading of OVA (ovalbumin) and controlled release capability, biocompatibility, tunability of surface functionality and immunopotentiating activity. In addition, the particles are antigen presenting cells (APCs) targeted by specific interaction with ß-glucan specific receptors on the surface of APCs, which can enhance the uptake and sustained proteolytic processing of antigens and induce APC maturation. Eventually, potent Th1 and Th2-type immune responses are aroused. The size and shape of the particles have a significant impact on the antigen uptake and immunoadjuvant activity. The degree of antigen uptake enhancement is ranked in the following order: PS HSP@glucan (nanoscale spherical) > E. coli HSP@glucan (micron-sized rod-like) > S. aureus HSP@glucan (micron-sized spherical). The PS HSP@glucan is more apt to induce a Th1-type immune response, while the E. coli HSP@glucan is more apt to induce a Th2-type immune response. The particles may thus provide a promising strategy for development of novel vaccine delivery systems for inducing robust humoral and cellular immune responses against infectious diseases and cancers.

Characterization of the aminated agarose nanoparticles labeled with fluorescein isothiocyanate.

Incorporating an organic fluorescence agent into nanoparticles can significantly promote its fluorescent efficiency. In this article, a novel fluorescein isothiocyanate labeling aminated agarose (FITC-AA) was synthesized and tested as an effective fluorescent labeling agent. FITC-AA could spontaneously form nanoparticles with a diameter less than 200 nm below 37°C due to gelling effect of the agarose. Cell culture experiments confirmed that 3T3 fibroblast cells could be marked by fluorescent FITC-AA nanoparticles and the labeling time sustained longer than by FITC alone. This finding demonstrates that the fluorescent labeling of cells can be enhanced when fluorescent nanoparticles are used as markers.

Recent progress in protein imprinting technology.

Protein-imprinted materials have drawn great attention nowadays for their promising application in biotechnology and biomedical engineering. Despite the success of molecular imprinting technique of small molecules in chemical and biomedical industry, imprinting of large molecules especially biomacromolecules remains a challenge. In recent years, however, a number of significant protein imprints have been reported, some of which may have great potential in applications for chromatography and biosensors. In this article, we review current development and patents on various protein imprinting approaches and materials developed recently. The advantages and disadvantages of the methods are discussed, and the trends are also highlighted.