Formulation development of a stable influenza recombinant neuraminidase vaccine candidate.

Current influenza vaccines could be augmented by including recombinant neuraminidase (rNA) protein antigen to broaden protective immunity and improve efficacy. Toward this goal, we investigated formulation conditions to optimize rNA physicochemical stability. When rNA in sodium phosphate saline buffer (NaPBS) was frozen and thawed (F/T), the tetrameric structure transitioned from a "closed" to an "open" conformation, negatively impacting functional activity.

Development of an In Vitro Test Method to Replace an Animal-Based Potency Test for Pertactin Antigen in Multivalent Vaccines.

There is increasing interest to replace animal-based potency assays used routinely to test vaccines, since they are highly variable, are costly, and present ethical concerns. The development of relevant in vitro assays is part of the solution. Using pertactin (PRN) antigen as an example in DTaP-IPV (diphtheria, tetanus, acellular pertussis, and inactivated poliovirus) vaccines, a PRN antigenicity ELISA was developed using two monoclonal antibodies with a high affinity to unique PRN epitopes, relevance to human immune responses, and evidence of functionality.

Epitope Profiling of Diphtheria Toxoid Provides Enhanced Monitoring for Consistency Testing during Manufacturing Process Changes.

In the vaccine industry, multiple physicochemical, immunological, and analytical methods are applied throughout the manufacturing process to characterize and monitor the quality of vaccines. Presented here is the Single Epitope Antigenicity Test (SEAT), an innovative, quantitative epitope profiling method which provides an extended immunochemical analysis for diphtheria toxoid (DTxd) to be used for consistency testing during manufacturing process changes. The method uses BioLayer Interferometry (BLI) and a panel of monoclonal antibodies (mAbs) to independently assess nine individual antigenic sites of DTxd.

Replacing the in vivo toxin challenge test with an in vitro assay for assessment of potency for diphtheria toxoid containing vaccines.

Replacement of the potency tests for diphtheria vaccines is a high priority for the international initiative to reduce, refine, and replace animal use in vaccine testing. Diphtheria toxoid containing vaccine products marketed in the US currently require potency testing by the United States Public Health Service (USPHS) test, which includes an in vivo passive protection test with a diphtheria toxin challenge. Here we describe an in vitro Diphtheria Vero Cell (DVC) assay which combines the immunization approach from the USPHS test and the use of a cell based neutralization assay for serological testing of vaccine potency.

An in vitro functional assay to measure the biological activity of TB vaccine candidate H4-IC31.

Potency assays for vaccine products are an important regulatory requirement, and are used to assess product quality and consistency prior to lot release for clinical testing. Ideally they measure an established correlate of efficacy or protection. In cases where there is no known correlate of protection, however, a functional assay that measures a biological response to a vaccine can be applied as a potency assay.

Flow cytometry: An efficient method for antigenicity measurement and particle characterization on an adjuvanted vaccine candidate H4-IC31 for tuberculosis.

We have developed an accurate, precise and stability-indicating flow cytometry (FC) based assay to directly measure antigenicity of H4 protein (also known as HyVac4) in a vaccine formulation of H4-IC31, without desorbing the H4 protein from the IC31 adjuvant. This method involves immuno-staining of H4-IC31 complex with anti-H4 monoclonal antibodies (mAbs) followed by FC analysis. The assay is not only able to consistently measure H4 antigenicity levels in H4-IC31 stored under normal condition at 2-8°C, but also able to detect changes in H4 antigenicity after H4-IC31 undergoes heat stress or freeze-thawing.

Passive protection of mice against Streptococcus pneumoniae challenge by naturally occurring and vaccine-induced human anti-PhtD antibodies.

Currently marketed Streptococcus pneumoniae vaccines are based on polysaccharide capsular antigens from the most common strains. Pneumococcal histidine triad protein D (PhtD) is a conserved surface protein that is being evaluated as a candidate for a vaccine with improved serotype coverage. Here, we measured the functional activity of human anti-PhtD antibodies in a passive protection model wherein mice were challenged with a lethal dose of S.

Neutralizing antibodies elicited by a novel detoxified pneumolysin derivative, PlyD1, provide protection against both pneumococcal infection and lung injury.

Streptococcus pneumoniae pneumolysin (PLY) is a virulence factor that causes toxic effects contributing to pneumococcal pneumonia. To date, deriving a PLY candidate vaccine with the appropriate detoxification and immune profile has been challenging. A pneumolysin protein that is appropriately detoxified and that retains its immunogenicity is a desirable vaccine candidate.

Formulation, stability and immunogenicity of a trivalent pneumococcal protein vaccine formulated with aluminum salt adjuvants.

We investigated the immunogenicity, stability and adsorption properties of an experimental pneumococcal vaccine composed of three protein vaccine antigens; Pneumococcal histidine triad protein D, (PhtD), Pneumococcal choline-binding protein A (PcpA) and genetically detoxified pneumolysin D1 (PlyD1) formulated with aluminum salt adjuvants. Immunogenicity studies conducted in BALB/c mice showed that antibody responses to each antigen adjuvanted with aluminum hydroxide (AH) were significantly higher than when adjuvanted with aluminum phosphate (AP) or formulated without adjuvant. Lower microenvironment pH and decreased strength of antigen adsorption significantly improved the stability of antigens.