The present disclosure provides compositions and methods for detecting the presence of neutralizing antibodies in a sample. Unlike conventional assays, the methods provided herein do not require the use of live virus or virus pseudoparticles to identify neutralizing antibodies.

Timely development of vaccines and antiviral drugs is critical to control the COVID-19 pandemic. Current methods for quantifying vaccine-induced neutralizing antibodies involve the use of pseudoviruses, such as the SARS-CoV-2 spike protein (S) pseudotyped lentivirus. However, these pseudoviruses contain structural proteins foreign to SARS-CoV-2, and require days to infect and express reporter genes. Here, the present application discloses composition and methodology for making and using a new hybrid alphavirus-SARS-CoV-2 (Ha-CoV-2) particle for rapid and accurate quantification of neutralization antibodies and viral variants.

Provided, herein, in certain embodiments are virus-like particles such as synthetic enveloped VLPs or synthetic membrane VLPs. In some embodiments, the VLPs comprise a lipid bilayer. In some embodiments, the VLPs comprise a purified antigen anchored to the lipid bilayer. Some embodiments relate to vaccines comprising the VLP, methods of using the vaccine, and methods of making the vaccine or VLP.

The present disclosure provides compositions and methods for detecting the presence of neutralizing antibodies in a sample. Unlike conventional assays, the methods provided herein do not require the use of live virus or virus pseudoparticles to identify neutralizing antibodies.

The present invention provides an mRNA nanocapsule and use thereof, comprising a virus-like particle (VLP) formed by self-assembly of a plurality of capsid proteins (CPs), an mRNA encoding Cas13 protein, and a guide RNA. The mRNA includes a capsid protein binding tag to be encapsidated in the VLP, so that the mRNA can stably enter cells, and the Cas13 protein could be translated.

Disclosed herein are methods, systems, and compositions comprising genetically modified probiotic microorganisms. In some embodiments, the genetically modified probiotic microorganisms produce at least one viral coat protein and/or at least one fusion protein comprising an antigenic polypeptide linked to a viral coat protein.

The present invention is directed to novel immunogenic compositions that protect swine from disease caused by porcine epidemic diarrhea virus (PEDV). The compositions of the invention provide virus-like particles (VLPs) whose effectiveness is enhanced by the selection of preferred adjuvants.

A method of producing a virus like particle (VLP) in a plant, and compositions comprising VLPs, are provided. The method involves introducing a nucleic acid comprising a regulatory region active in the plant and operatively linked to a chimeric nucleotide sequence encoding, in series, an ectodomain from a virus trimeric surface protein or fragment thereof, fused to an influenza transmembrane domain and cytoplasmic tail, into the plant, or portion of the plant, the ectodomain is from a non-influenza virus trimeric surface protein and heterologous with respect to the influenza transmembrane domain, and the cytoplasmic tail. The plant or portion of the plant are incubated under conditions that permit the expression of the nucleic acid, thereby producing the VLP. A VLP produced by this method are also provided.

A method of producing a virus like particle (VLP) in a plant, and compositions comprising VLPs, are provided. The method involves introducing a nucleic acid comprising a regulatory region active in the plant and operatively linked to a chimeric nucleotide sequence encoding, in series, an ectodomain from a virus trimeric surface protein or fragment thereof, fused to an influenza transmembrane domain and cytoplasmic tail, into the plant, or portion of the plant, the ectodomain is from a non-influenza virus trimeric surface protein and heterologous with respect to the influenza transmembrane domain, and the cytoplasmic tail. The plant or portion of the plant are incubated under conditions that permit the expression of the nucleic acid, thereby producing the VLP. A VLP produced by this method are also provided.

The present invention relates i.a. to a recombinant avian coronavirus spike protein or fragment thereof comprising a mutation at amino acid position 267 to Cysteine. Further, the present invention relates to an immunogenic composition comprising an avian coronavirus with such spike protein.