Methods are provided for identifying and selecting antibodies that are internalized into cells via the macropinocytosis pathway. Additionally antibodies that are internalized via this pathway are provided as well as immunoconjugates comprising such antibodies.

Disclosed herein are methods for the direct readout of proteoforms and complexes thereof, such as immunoglobulins. The method may comprise ionizing a sample with an ionizer, wherein the sample comprises a mixture of different proteoforms or complexes thereof; detecting a multiplicity of ions generated by the ionization of the sample with a current detector; determining ion masses for each of the multiplicity of ions detected with the current detector with a mass analyzer; generating a mass-domain spectrum from the ion masses with the mass analyzer. The method may also comprise determining one or more metrics capturing the heterogeneity or relative abundance of proteoforms.

Herein is reported a method for the determination of the amount of a bivalent antibody in a serum or plasma sample obtained from a non-human experimental animal, whereby the antibody comprises one or more mutations in the Fc-region compared to the corresponding wild-type Fc-region that has a sequence of SEQ ID NO: 01, 02, or 03, wherein the method comprises the following steps a) immobilizing a non-antibody polypeptide to which more than one copy of the antigen of the antibody is covalently conjugated on a solid surface, b) incubating the immobilized antigen with the sample to form an immobilized antigen-antibody complex, c) incubating the immobilized antigen-antibody complex with the antigen conjugated to a detectable label to form an immobilized ternary complex, and d) determining the amount of the antibody by determining the amount of the detectable label in the immobilized ternary complex.

Methods and reagents for diagnosing, prognosing, and treating systemic lupus erythematosus (SLE) are disclosed, involving calculating an SLE risk score for a subject based on a level of each of an erythrocyte C4d (EC4d) marker, a B-cell C4d (BC4d) marker, anti-nuclear antibodies (ANA), and optional rule-out markers.

Provided herein are compositions and methods to identify a binding element (e.g., peptide, peptoid, or protein) that can be bound by an immunoreceptor (e.g., antibody). The binding element can be provided in a target binding unit comprising two binding elements separated by a spacer such that the two binding elements simultaneously bind to a single molecule comprising an antigen binding domain of an antibody. The present disclosure provides various methods to construct the spacer. The identified binding elements can be further used to manufacture an array which can be used to profile antibodies obtained from a blood sample.

Compositions and methods relating to antibodies that specifically bind to TGF-beta binding proteins are provided. These methods and compositions relate to altering bone mineral density by interfering with the interaction between a TGF-beta binding protein sclerostin and a TGF-beta superfamily member, particularly a bone morphogenic protein. Increasing bone mineral density has uses in diseases and conditions in which low bone mineral density typifies the condition, such as osteopenia, osteoporosis, and bone fractures.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the strain of coronavirus that causes coronavirus disease 2019 (COVID-19), the respiratory illness responsible for the COVID-19 pandemic. Antibodies produced from an immune response against SARS-CoV-2 infection are used to analyze prior exposure to the virus. The present invention provides methods for detecting antibodies in response to SARS-CoV-2 infection in a single multiplex immunoassay.

The present invention generally pertains to methods of characterizing antibodies and related products. In particular, the present invention pertains to the use of immunoprecipitation and native strong cation exchange chromatography-mass spectrometry to specifically and sensitively detected and quantitate antibodies and related products in a sample.

Described herein is a method for assessing disulfide bond reduction potential of a protein of interest comprising the following steps: Providing a cell culture fluid sample comprising mammalian cells expressing a protein of interest at a concentration within the range of between 0.2 g/l to 10 g/l Filtering said cell culture fluid sample over at least one filter Displacing O.sub.2 in the filtered cell culture fluid sample Collecting at least one sample of the O.sub.2-displaced filtered cell culture fluid sample Separating the proteins in said at least one O.sub.2-displaced, filtered cell culture fluid sample according to their size under non-denaturing conditions Determining the disulfide bond reduction potential of the protein of interest.

The present invention is directed to particular monoclonal antibodies and fragments thereof that find use in the detection, prevention and treatment of Streptococcus pneumoniae infections. In particular, these antibodies may kill Streptococcus pneumoniae or limit the replication of Streptococcus pneumoniae. Also disclosed are improved methods for producing such monoclonal antibodies.