A multispecific antibody against SARS-CoV-2 prevents immune escape in vitro and confers prophylactic protection in vivo.

Despite effective countermeasures, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) persists worldwide because of its ability to diversify and evade human immunity. This evasion stems from amino acid substitutions, particularly in the receptor binding domain (RBD) of the spike protein that confers resistance to vaccine-induced antibodies and antibody therapeutics. To constrain viral escape through resistance mutations, we combined antibody variable regions that recognize different RBD sites into multispecific antibodies.

Mosaic quadrivalent influenza vaccine single nanoparticle characterization.

Recent work by our laboratory and others indicates that co-display of multiple antigens on protein-based nanoparticles may be key to induce cross-reactive antibodies that provide broad protection against disease. To reach the ultimate goal of a universal vaccine for seasonal influenza, a mosaic influenza nanoparticle vaccine (FluMos-v1) was developed for clinical trial (NCT04896086). FluMos-v1 is unique in that it is designed to co-display four recently circulating haemagglutinin (HA) strains; however, current vaccine analysis techniques are limited to nanoparticle population analysis, thus, are unable to determine the valency of an individual nanoparticle.

Soluble prefusion-closed HIV-envelope trimers with glycan-covered bases.

Soluble HIV-1-envelope (Env) trimers elicit immune responses that target their solvent-exposed protein bases, the result of removing these trimers from their native membrane-bound context. To assess whether glycosylation could limit these base responses, we introduced sequons encoding potential -linked glycosylation sites (PNGSs) into base-proximal regions. Expression and antigenic analyses indicated trimers bearing six-introduced PNGSs to have reduced base recognition.

Site-Specific Fluorescent Labeling of Hemagglutinin-Specific Antigen Binding Fragment through Amine Chemistry Revealed by Mass Spectrometry.

To capture the structure of assembled hemagglutinin (HA) nanoparticles at single-particle resolution, HA-specific antigen binding fragments (Fabs) were labeled by fluorescent (FLR) dyes as probes to highlight the HA trimers displayed on the assembled tetravalent HA nanoparticles for a qualitative localization microscopic study. The FLR dyes were conjugated to the Fabs through -hydroxysuccinimide (NHS) ester mediated amine coupling chemistry. The labeling profile, including labeling ratio, distribution, and site-specific labeling occupancy, can affect the imaging results and introduce inconsistency.

Development and validation of a mass spectrometry based analytical method to quantify the ratios in hemagglutinin trimers in quadrivalent influenza nanoparticle vaccine - FluMos-v1.

A quadrivalent influenza nanoparticle vaccine (FluMos-v1) offers long-lasting protection against multiple influenza virus strains and is composed of four strains of hemagglutinin trimer (HAT) assembled around a pentamer core. Here we report an LC-MS/MS analytical development and validation method to measure the percentage of each HAT component in FluMos-v1.