An anti-CTLA4 (cytotoxic T lymphocyte associated antigen 4) and anti-PD-1 (programmed cell death 1) bifunctional antibody. a pharmaceutical composition thereof and use thereof. Particularly, the anti-CLTA4 and anti-PD-1 bifunctional antibody comprises a first protein functional domain that targets PD-1 and a second protein functional domain that targets CTLA-4. The bifunctional antibody can bind to CTLA-4 and PD-1 specifically, relieve immunosuppression of CTLA4 and PD-1 on an organism specifically, activate T lymphocytes, and thus has good application prospects.

The current invention reports a method for producing an antibody comprising the steps of a) providing a plurality of hybridoma cells each expressing an antibody, b) determining the time dependent amount of said antibody bound to the respective antigen by surface plasmon resonance at different temperatures and different antibody concentrations, c) calculating with the time dependent amount determined in b) based on equations (II) to (XIII) at least the thermodynamic parameters (i) standard association binding entropy (ΔS°‡ass), (ii) standard dissociation binding entropy (ΔS°‡diss), (iii) standard binding entropy (ΔS°), (iv) free standard binding enthalpy (ΔG°), (v) standard dissociation free binding enthalpy (ΔG°‡diss), (vi) standard association free binding enthalpy (ΔG°‡ass), (vii) −TΔS°, (viii) dissociation rate constant k.sub.d, (ix) equilibrium binding constant K.sub.D, and (x) association rate constant k.sub.a, d) selecting a hybridoma cell producing an antibody with at least two of the following: i) a standard association binding entropy of less than 10 J/K*mol, ii) an absolute standard dissociation binding entropy of 100 J/mol*K or more, iii) an absolute standard binding entropy of 100 J/mol*K or more, e) producing an antibody by cultivating said selected cell under conditions suitable for the expression of said antibody and recovering said antibody from the cells or/and the cultivation medium.

Compositions and methods for analyzing disulfide bonds are provided. An exemplary method includes preparing peptide standards having no disulfide bonds, scrambled disulfide bond peptide standards, and native disulfide bond peptide standards according to the sequence of the region of the protein drug product that includes the disulfide bond, digesting a sample of protein drug product into peptides, separating the protein drug product peptides, analyzing the protein drug product peptides and the peptide standards, identifying scrambled and native disulfide bond peptides by retention time, and quantifying the level of scrambled disulfide bond peptides.

The present invention provides a method for quantifying a monoclonal (M-) protein in a sample of a subject, the method comprising the steps of:—subjecting a serum sample of a subject to serum protein electrophoresis (SPE) in a gel, preferably serum protein electrophoresis in an agarose gel, to separate serum proteins into different serum protein fractions, optionally followed by immunofixation electrophoresis (IFE) and further optionally involving immunostaining of the gel;—excising from said gel a gel part comprising, or suspected of comprising, a M-protein;—performing an enzymatic digestion of proteins present in said gel part in order to provide a peptide digest comprising at least one M-protein peptide;—subjecting said peptide digest comprising said at least one M-protein peptide to liquid chromatography-mass spectrometry (LC-MS) to determine a quantity of said at least one M-protein peptide, thereby quantifying said M-protein in said sample.

Models and methods related to targeting binding immunoglobulin protein (BiP) are described, where the models and methods allow identification and analysis of protein folding and misfolding.

The present invention relates to the field of protein characterization, and in particular to methods for identifying critical quality attributes of therapeutic proteins expressed in host cells by implementing a workflow including using a competitive binding assay with insufficient antigen followed by SCX-MS.

The present invention pertains to methods for characterizing proteins in a sample using native capillary electrophoresis-mass spectrometry. The present invention pertains to methods for detecting and/or discriminating between post-translational modification variants of an antibody of interest in a sample, detecting and/or discriminating between antibodies in an antibody mixture, and characterizing monospecific antibody side products in a bispecific antibody sample.

Disclosed herein are methods of high-throughput mapping of viral neutralizing antibody epitopes. Also disclosed are in vitro immunoprecipitation-based adeno-associated virus Barcode-Seq-based methods of mapping viral neutralizing antibody epitopes. In some embodiments, a method of high-throughput mapping of viral NtAb conformational epitopes can be utilized, which may comprise HP scanning of mutant viral libraries, immunoprecipitation (IP), and/or next-generation sequencing (NGS) technology. In some embodiments, a method of identifying one or more dominant epitopes in a viral vector may comprise contacting a mutant capsid of a virus with serum from a subject previously exposed to the virus and immunoprecipitating serum immunoglobulins from the serum. In various embodiments, the viral vector may be an AAV vector.

The invention provides methods for identifying protein modulators (e.g., antibody agonists) of eukaryotic cells. The methods typically involve expressing a combinatorial agent library (e.g., via lentiviral vectors) inside a eukaryotic cell type (e.g., a mammalian cell) and then directly selecting for agents (e.g., antibodies) that are agonist of a target molecule (e.g., a signaling receptor) that modulates a phenotype of or elicits a cellular response in the cell. Some related methods involve co-culturing a cell expressing a combinatorial agent library and a second cell, and then selecting agents that modulate a phenotype of or elicit a cellular response in the second cell. Preferably, the agents are antibodies and are introduced into and expressed in the starting cells under conditions each individual cell expresses no more than 3 different members of the antibody library. In addition, the invention provides methods for identifying protein agonists that capable of reprograming or trans-differentiating a target cell. Also provided in the invention are specific agonist antibodies of signaling receptors or biomolecules that modulate a phenotype or effectuate a cellular response in a eukaryotic cell (e.g., agonist antibodies of EpoR, TpoR or G-CSFR). Further provided in the invention are methods for selecting from combinatorial antibody libraries bispecific antibodies that can regulate cell phenotypes.

The present invention relates to a kit of parts and methods for determining the presence and quantity of one or more TNF-α inhibitor drugs and/or anti-TNF-α inhibitor drug antibodies in one or more biological samples each comprising less than 200 μl, the method comprising the steps of providing a reaction liquid comprising the sample, a first TNF-α conjugate comprising TNF-α and a first conjugated moiety and a second TNF-α conjugate comprising TNF-α and a second conjugated moiety, said second moiety being capable of generating or ameliorating a detectable signal in the presence of a molecular complex comprising a TNF-α inhibitor, followed by detecting the change in signal when the complex between the TNF-α inhibitor drug, the first TNF-α conjugate and a the second TNF-α conjugate forms.