The disclosure belongs to the field of biotechnology, and in particular to a blocking ELISA kit for detecting an antibody to swine acute diarrhea syndrome coronavirus (SADS-CoV) N protein. The kit includes an enzyme plate coated with SADS-CoV N protein, an HRP-labeled mouse anti-SADS-CoV N protein monoclonal antibody (mAb), a positive serum control, and a negative serum control. The kit may detect positive sera diluted at 1:512, with no cross-reaction with positive sera against porcine epidemic diarrhea virus (PEDV), transmissible gasteroenteritis virus (TGEV) and porcine deltacoronavinis (PDCoV) etc., and the intrabatch and interbatch coefficient of variation is less than 10%. The comparison result with the indirect immunofluorescence test shows that the concordance rate of the blocking ELISA kit of the present disclosure is 99.6%, the Kappa value is 0.91, and the blocking ELISA method established by the present disclosure is highly consistent with IFA.

The present disclosure relates to fusion protein compositions and methods of reducing and treating viral infections. The fusion proteins include a polypeptide comprising a b1 domain, or a derivative or fragment thereof, of a neuropilin; an ACE2 domain, or a derivative or a fragment thereof, of an angiotensin converting enzyme 2; and or an immunoglobulin domain. Both the b1 and ACE2 domains are capable of binding to a coat protein of a virus selected from the group consisting of herpesviridae, papillomaviridae, coronaviridae, flaviviridae, togaviridae, bomaviridae, bunyaviridae, filoviridae, orthomyxoviridae, paramyxoviridae, pneumoviridae, and retro viridae. In some embodiments, the b1 domain, or a derivative or fragment thereof, and/or the (ACE2) domain, can be used to specifically bind S proteins of COVID-19 particles.

A peptide which binds to SARS-CoV-2 and its usage are provided. The peptide which binds to SARS-CoV-2 comprises one or more structural domain comprising CDR3 consisting of an amino acid sequence of any of SEQ ID NOs: 1 to 9 or an amino acid sequence obtained by substituting at least one amino acid in the amino acid sequence with another amino acid.

The present invention provides epitope peptides which are derived from SARS-CoV-2 proteins and have the ability to induce cytotoxic T cells. The present invention also provides polynucleotides encoding the peptides, antigen-presenting cells that present the peptides, and cytotoxic T cells that target the peptides, and methods of inducing the antigen-presenting cells or CTLs. The present invention further provides compositions and pharmaceutical compositions containing them as active ingredients. Moreover, the present invention provides methods of treating and/or preventing coronavirus infectious diseases, and/or suppressing the aggravation of coronavirus infectious diseases by using the peptides, polynucleotides, antigen-presenting cells, cytotoxic T cells, or pharmaceutical compositions of the present invention. The present invention also provides methods of inducing an immune response against coronavirus infection. Furthermore, the present invention provides methods of examining the history of coronavirus infection by detecting TCR sequences of a subject.

Disclosed is an antigen peptide with an infectious bronchitis virus (IBV)-specific neutralizing epitope, in which the peptide is a cyclic polypeptide, and the amino acid sequence of the peptide is CSCPYVSYGRFCIQPDGSIKQC. Also disclosed are an IBV specific antibody and a preparation method thereof. Further disclosed is an ELISA method as an alternative to the neutralization potency assay. The disclosure also discloses an ELISA detection kit, and using the established pELISA method to detect IBV antibodies, it is found that the method is positively correlated with anti-IBV neutralizing antibodies, which may be used to evaluate the immune effect of IBV vaccines on IBV infected chickens and to determine the antibody level, thereby benefiting the health management of chicken flocks.

The present invention provides monoclonal antibodies that neutralize SARS-CoV2 and methods of use thereof. The antibodies described herein can be used to treat SARS-CoV2 infections and symptoms thereof.

The present disclosure belongs to the field of immune technology, and particularly discloses a SARS-CoV-2 RBD-specific monoclonal antibody including a heavy chain having an amino acid sequence set forth in SEQ ID NO: 1 and a light chain having an amino acid sequence set forth in SEQ ID NO: 2. The present disclosure further discloses a linear epitope of the SARS-CoV-2 RBD-specific monoclonal antibody having an amino acid sequence set forth in SEQ ID NO: 3. The SARS-CoV-2 RBD-specific monoclonal antibody and the linear epitope thereof of the present disclosure are critical for research and development of vaccines and micromolecule drugs, diagnosis, prevention and treatment of COVID-19.

The instant disclosure provides antibodies and antigen-binding fragments thereof that can bind to a SARS-CoV-2 antigen and, in certain embodiments, are capable of neutralizing a SARS-CoV-2 infection. Also provided are polynucleotides that encode an antibody or antigen-binding fragment, vectors and host cells that comprise a polynucleotide, pharmaceutical compositions, and methods of using the presently disclosed antibodies, antigen-binding fragments, polynucleotides, vectors, host cells, and compositions to treat or diagnose a SARS-CoV-2 infection.

Disclosed herein include antibodies or fragments thereof having specificity to a sarbecovirus spike protein. Also provided are compositions, methods, and kits for using said antibodies or fragments thereof for preventing or treating, for example a coronavirus infection.

Disclosed are a fully human broad-spectrum neutralizing antibody against coronavirus, and the use thereof. Specifically disclosed are a fully human monoclonal antibody against an S2 region of coronavirus S protein, a nucleic acid sequence encoding the antibody, and a preparation method therefor. The antibody can effectively bind to and neutralize a variety of coronaviruses in a broad spectrum manner, and can be used for preventing and treating diseases related to coronavirus infection, such as SARS-CoV-2. Further disclosed is the potential use thereof in vaccine design.