Disclosed is a calibrator comprising IgA having a biotin group and a biotin-binding site, the calibrator being used to obtain a concentration of an IgA aggregate in a sample.

The present invention provides a compound for the sequestration of undesirable antibodies (e.g. related to an autoimmune disease) in a patient. The compound comprises an inert biopolymer scaffold and at least a first peptide n-mer of the general formula P(-S-P).sub.(n-1) and a second peptide n-mer of the general formula P(-S-P).sub.(n-1); wherein, independently for each occurrence, P is a peptide with a sequence length of 2-13 amino acids and S is a non-peptide spacer, wherein, independently for each of the peptide n-mers, n is an integer of at least 1, wherein each of the peptide n-mers is bound to the biopolymer scaffold. Also provided are pharmaceutical compositions comprising the compound, as well as a method of sequestering one or more antibodies present in an individual and a method of inhibiting an immune reaction to a treatment with an active agent.

Methods are provided for isolation of immunoglobulin G (IgG) from plasma, where IgG is initially fractioned by salt precipitation, followed by successive ion exchange steps in which IgG appears in unbound, flow-through fractions of the ion exchange steps. Some embodiments employ successive anion exchange steps. Other embodiments employ an anion exchange step followed by application of flow-through of the anion exchange step to a cation exchange step, with IgG collected in flow-through fractions from the cation exchange step. IgG is collected at high yield (typically about 75% or greater) and high purity. Avoidance of binding and elution from chromatography media simplifies processing and scale up without sacrificing IgG quality or yield.

Processes and methods of purifying or separating Single Domain Antigen Binding (SDAB) molecules that include one or more single binding domains (e.g., one or more nanobody molecules), substantially devoid of a complementary antibody domain and an immunoglobulin constant region, using Protein A-based affinity chromatography, are disclosed.

The present disclosure relates to, inter alia, a method of quantitating an amount of an antibody molecule from a mixture comprising two or more antibody molecules, comprising separating each of the two or more antibody molecules from the mixture by hydrophobic interaction chromatography high performance liquid chromatography (HIC-HPLC) and quantitating an amount of each antibody molecule, wherein the molecular weight of each antibody molecule is within 15 kDa of any other antibody molecule in the mixture and either each antibody molecule is different from another antibody molecule in the mixture by more than about 0.25 unit on the Kyte & Doolittle hydropathy scale or each of the antibody molecules when run alone on HIC-HPLC elutes at distinct run time with little overlap from the other antibody molecules in the mixture, or both.

The present invention relates to new methods for the purification of immunoglobulins from cell culture harvest. These methods are characterized by cleaning steps preceding an initial capture chromatography step. Preferably, the initial capture chromatography is an affinity chromatography and the pre-capture cleaning effect is obtained by flocculation and filtration. By using such pre-capture cleaning steps, an improved quality of the eluted immunoglobulin from the capture matrix is achieved. Furthermore, the enhanced clarification of the cell culture liquid results in reduced precipitations during affinity chromatography and thus increases the lifetimes of the expensive affinity resin. This is an important improvement for immunoglobulin purification in large scale production. The present invention further relates to sequential polishing chromatographies and filtration steps downstream to the capture chromatography, yielding immunoglobulins of high purity.

A method is provided for purifying physiologically active proteins, especially antibodies, in order to remove impurities such as DNA contaminants and viruses with minimal loss of physiologically active proteins. The physiologically active protein is introduced into an aqueous solution of low conductivity at a pH of below the isoelectric point of the physiologically active protein to precipitate impurities as particles. The particles are removed, leaving a purified physiologically active protein.

The present application provides heteromultimeric proteins, such as bispecific antibodies, comprising a first antibody heavy chain constant domain 3 (CH3)-containing polypeptide having a substitution relative to a wildtype CH3 domain at amino acid position 354 with a bulky hydrophobic amino acid, and/or a second CH3-containing polypeptide comprising a substitution relative to a wildtype CH3 domain at ammo acid position 347 with a negatively charged amino acid residue. Also provided are polypeptides, nucleic acids and vectors encoding such polypeptides, pharmaceutical compositions, methods of preparation and methods of treatment using the heteromultimeric proteins.

Disclosed herein are compositions and uses thereof for detection of disease-related antibodies. The methods include contacting a biological sample with a solid support comprising one or more antigens that bind one or more therapeutic monoclonal antibodies, and detecting the disease-related antibody in the biological sample using an electrophoretic method.

In certain embodiments, the present invention provides novel antibody purification methods and systems using a potentially simple and cost-efficient means. In some embodiments, customized Z-33 derived from Staphylococcus aureus Protein A is used to construct immuno-amphiphile molecules which can assemble into immunofibers in aqueous solution with bioactive epitopes on the surface and have IgG binding ability.