A Polysaccharide-RBD-Fc-Conjugated COVID-19 Vaccine, SCTV01A, Showed High Immunogenicity and Low Toxicity in Animal Models.

We previously developed a polysaccharide--RBD-conjugated nanoparticle vaccine which induced protective efficacy against SARS-CoV-2 in a mouse model. Here, we newly developed a vaccine, SCTV01A, by chemically conjugating recombinant SARS-CoV-2 RBD-Fc and PPS14 ( serotype type 14 capsular polysaccharide). The immunogenicity and toxicity of SCTV01A were evaluated in animal models.

Feasibility Studies of Nebulized SARS-CoV-2 Neutralizing Antibody in Mice and Cynomolgus Monkeys.

Purpose: Neutralizing antibodies, administrated through intravenous infusion, have shown to be highly efficacious in treating mild and moderate COVID-19 caused by SARS-CoV-2 infection in the lung. However, antibodies do not transport across the plasma-lung barrier efficiently, and up to 100 mg/kg dose was used in human causing significant supply and cost burdens. This study was to explore the feasibility of nebulized antibodies inhalation delivery as an alternative route.

Immunogenicity correlation in cynomolgus monkeys between Luminex-based total IgG immunoassay and pseudovirion-based neutralization assay for a 14-valent recombinant human papillomavirus vaccine.

A new virus-like particle based vaccine covering 14 types of high-risk and disease-inducing human papillomavirus (HPV) can offer better coverage against HPV-induced diseases, particularly cervical cancers. However, the assessment of immunogenicity of the vaccine is an important task, representing not only its significant clinical characteristics, but also a major challenge, in terms of both the suitability of methods and the clinical sample testing throughput supporting clinical development. This work covers the development and evaluation of a method based on Luminex technology (a coded-bead and flow-cytometric approach) to assess the HPV-type specific total immunoglobulin G (IgG).

Potential Hepatitis B Vaccine Formulation Prepared by Uniform-Sized Lipid Hybrid PLA Microparticles with Adsorbed Hepatitis B Surface Antigen.

For the purpose of strengthening the immunogenicity of the hepatitis B vaccine, which contains hepatitis B surface antigen (HBsAg), the development of biodegradable poly(lactic acid) (PLA) microparticles (MPs) modified with the cationic surfactant didodecyldimethylammonium bromide (DDAB) was attempted. DDAB-PLA MPs with an uniform size of about 1 μm were prepared in a simple and mild way. DDAB-PLA MPs with increased surface charge enhanced antigen adsorption capacity compared to plain PLA MPs.

Fabrication and characterization of DDAB/PLA-alginate composite microcapsules as single-shot vaccine.

The most effective method to reduce chronic hepatitis B virus infection is the universal implementation of vaccination. The commercial aluminum-based vaccines need multiple-injection protocols for complete protection resulting in poor compliance in developing countries. It is necessary to develop single-shot vaccine formulations.

Facile fabrication of varisized calcium carbonate microspheres as vaccine adjuvants.

Functional calcium carbonate (CaCO) particles of micron and submicron sizes used in catalysis and biomedicine have attracted considerable attention for decades. In this paper, the process parameters for CaCO crystallization were systematically investigated. Our experimental results demonstrated the significance of temperature during fabrication.

Adjuvanticity Regulation by Biodegradable Polymeric Nano/microparticle Size.

Polymeric nano/microparticles as vaccine adjuvants have been researched in experimental and clinical studies. A more profound understanding of how the physicochemical properties regulate specific immune responses has become a vital requirement. Here we prepared poly(d,l-lactic-co-glycolic acid) (PLGA) nano/microparticles with uniform sizes (500 nm, 900 nm, 2.

Pathogen-Mimicking Polymeric Nanoparticles based on Dopamine Polymerization as Vaccines Adjuvants Induce Robust Humoral and Cellular Immune Responses.

Aiming to enhance the immunogenicity of subunit vaccines, a novel antigen delivery and adjuvant system based on dopamine polymerization on the surface of poly(D,L-lactic-glycolic-acid) nanoparticles (NPs) with multiple mechanisms of immunity enhancement is developed. The mussel-inspired biomimetic polydopamine (pD) not only serves as a coating to NPs but also functionalizes NP surfaces. The method is facile and mild including simple incubation of the preformed NPs in the weak alkaline dopamine solution, and incorporation of hepatitis B surface antigen and TLR9 agonist unmethylated cytosine-guanine (CpG) motif with the pD surface.

Immunopotentiator-Loaded Polymeric Microparticles as Robust Adjuvant to Improve Vaccine Efficacy.

Purpose: Adjuvants are required to ensure the efficacy of subunit vaccines. Incorporating molecular immunopotentiators within particles could overcome drawbacks of molecular adjuvants (such as solubility and toxicity), and improve adjuvanticity of particles, achieving stronger adjuvant activity. Aim of this study is to evaluate the adjuvanticity of immunopotentiator-loaded polymeric particles for subunit vaccine.

pH-Responsive Poly(D,L-lactic-co-glycolic acid) Nanoparticles with Rapid Antigen Release Behavior Promote Immune Response.

In the quest to treat intracellular infectious diseases and virus infection, nanoparticles (NPs) have been considered to be efficient tools for inducing potent immune responses, specifically cellular immunity. Antigen processing and presenting by antigen presenting cells (APCs) could influence immune response, especially the priming of T-cell-mediated cellular immunity. Here, we fabricated pH-responsive poly(D,L-lactic-co-glycolic acid) (PLGA) NPs with rapid antigen intracellular release behavior in APCs.

Polycation-decorated PLA microspheres induce robust immune responses via commonly used parenteral administration routes.

Recombinant viral subunit-based vaccines have gained increasing attention due to their enhanced safety over the classic live-attenuated or inactivated vaccines. The low immunogenicity of the subunit antigen alone, however, requires the addition of an adjuvant to induce immunity. Particulate-based delivery systems have great potential for developing new vaccine adjuvants, compared to traditional aluminum-based saline adjuvants.

Immune responses to vaccines involving a combined antigen-nanoparticle mixture and nanoparticle-encapsulated antigen formulation.

Many physicochemical characteristics significantly influence the adjuvant effect of micro/nanoparticles; one critical factor is the kinetics of antigen exposure to the immune system by particle-adjuvanted vaccines. Here, we investigated how various antigen-nanoparticle formulations impacted antigen exposure to the immune system and the resultant antigen-specific immune responses. We formulated antigen with poly(lactic-co-glycolic acid) (PLGA) nanoparticles by encapsulating antigen within nanoparticles or by simply mixing soluble antigen with the nanoparticles.

Oral administration of Clostridium butyricum for modulating gastrointestinal microflora in mice.

This study aimed to evaluate the safety of Clostridium butyricum and to investigate the effect of C. butyricum on mice ecosystem in the intestinal tract by way of examining the population of different microorganisms isolated from caecal contents. We firstly evaluated the safety of C.