Dendritic cells support a proliferative antigen-specific T-cell response in the presence of poly(lactic-co-glycolic acid)

Engineered macromolecular Toll-like receptor agents and assemblies

Macromolecular Toll-like receptor (TLR) agents have been utilized as agonists and inhibitors in preclinical and clinical settings. These agents interface with the TLR class of innate immune receptors which recognize macromolecular ligands that are characteristic of pathogenic material. As such, many agents that have been historically investigated are derived from the natural macromolecules which activate or inhibit TLRs. This review covers recent research and clinically available TLR agents that are macromolecular or polymeric. Synthetic materials that have been found to interface with TLRs are also discussed. Assemblies of these materials are investigated in the context of improving stability or efficacy of ligands. Attention is given to strategies which modify or enhance the current agents and to future outlooks on the development of these agents.

Immunogenicity and protective efficacy of an inactivated Newcastle disease virus vaccine encapsulated in poly-(lactic-co-glycolic acid) nanoparticles

An immunization experiment was conducted in specific pathogen-free chickens with the inactivated Newcastle disease virus (NDV) vaccine encapsulated in the poly-(lactic-co-glycolic) acid (PLGA) nanoparticles (NP) to evaluate its immunogenicity and protective efficacy. The NDV vaccine was prepared by inactivating one virulent Indian strain of NDV belonging to Genotype VII by using beta-propiolactone. PLGA nanoparticles encapsulating inactivated NDV were prepared by the solvent evaporation method. Scanning electron microscopy and zeta sizer analysis revealed that the (PLGA+NDV) NP were spherical, with an average size of 300 nm, having a zeta potential of -6 mV. The encapsulation efficiency and loading efficiency were 72% and 2.4%, respectively. On immunization trial in chicken, the (PLGA+NDV) NP induced significantly (P < 0.0001) higher levels of HI and IgY antibodies with the peak HI titer of 2⁸ and higher expression of IL-4 mRNA. The consistency of higher antibody levels suggests slow and pulsatile release of the antigens from the (PLGA+NDV) NP. The nano-NDV vaccine also induced cell mediated immunity with higher expression of IFN-γ indicating strong Th1 mediated immune responses in contrast to the commercial oil adjuvanted inactivated NDV vaccine. Further, the (PLGA+NDV) NP afforded 100% protection against the virulent NDV challenge. Our results suggested that PLGA NP have adjuvant potential on induction of humoral as well as Th1 biased cell mediated immune responses and also enhanced protective efficacy of the inactivated NDV vaccine. This study provides an insight for development of PLGA NP based inactivated NDV vaccine using the same genotype circulating in the field as well as for other avian diseases at exigencies.

Progress of polymer-based strategies in fungal disease management: Designed for different roles

Fungal diseases have posed a great challenge to global health, but have fewer solutions compared to bacterial and viral infections. Development and application of new treatment modalities for fungi are limited by their inherent essential properties as eukaryotes. The microorganism identification and drug sensitivity analyze are limited by their proliferation rates. Moreover, there are currently no vaccines for prevention. Polymer science and related interdisciplinary technologies have revolutionized the field of fungal disease management. To date, numerous advanced polymer-based systems have been developed for management of fungal diseases, including prevention, diagnosis, treatment and monitoring. In this review, we provide an overview of current needs and advances in polymer-based strategies against fungal diseases. We high light various treatment modalities. Delivery systems of antifungal drugs, systems based on polymers' innate antifungal activities, and photodynamic therapies each follow their own mechanisms and unique design clues. We also discuss various prevention strategies including immunization and antifungal medical devices, and further describe point-of-care testing platforms as futuristic diagnostic and monitoring tools. The broad application of polymer-based strategies for both public and personal health management is prospected and integrated systems have become a promising direction. However, there is a gap between experimental studies and clinical translation. In future, well-designed in vivo trials should be conducted to reveal the underlying mechanisms and explore the efficacy as well as biosafety of polymer-based products.

Immune Cells Activating Biotin-Decorated PLGA Protein Carrier

Nanoparticle formulations have long been proposed as subunit vaccine carriers owing to their ability to entrap proteins and codeliver adjuvants. Poly(lactic-co-glycolic acid) (PLGA) remains one of the most studied polymers for controlled release and nanoparticle drug delivery, and numerous studies exist proposing PLGA particles as subunit vaccine carriers. In this work we report using PLGA nanoparticles modified with biotin (bNPs) to deliver proteins via adsorption and stimulate professional antigen-presenting cells (APCs). We present evidence showing bNPs are capable of retaining proteins through the biotin-avidin interaction. Surface accessible biotin bound both biotinylated catalase (bCAT) through avidin and streptavidin horseradish peroxidase (HRP). Analysis of the HRP found that activity on the bNPs was preserved once captured on the surface of bNP. Further, bNPs were found to have self-adjuvant properties, evidenced by bNP induced IL-1β, IL-18, and IL-12 production in vitro in APCs, thereby licensing the cells to generate Th1-type helper T cell responses. Cytokine production was reduced in avidin precoated bNPs (but not with other proteins), suggesting that the proinflammatory response is due in part to exposed biotin on the surface of bNPs. bNPs injected subcutaneously were localized to draining lymph nodes detectable after 28 days and were internalized by bronchoalveolar lavage dendritic cells and macrophages in mice in a dose-dependent manner when delivered intranasally. Taken together, these data provide evidence that bNPs should be explored further as potential adjuvanting carriers for subunit vaccines.