The invention relates to a method of reducing the amount of non-aggregate produce-related impurities (NAPRIs) in a buffered solution of monoclonal antibodies (mAbs), involving the use of a synthetic depth filter. The invention may be of use in the purification of monoclonal 5 antibodies.

The present invention is directed to a method of inactivating virus that is present during production of a polypeptide of interest. In particular, the present invention is directed to a method of on-column virus inactivation using a low pH and high salt wash solution that effectively inactivates viruses with minimum recovery loss of the polypeptide.

A population of antibodies including homogeneous antibodies in which N-linked complex sugar chains attached to asparagine (Asn) at position 297 of CH domains of Fc regions of two heavy chains on the left and the right of each antibody are sugar chains structurally different from each other is described as well as a method of producing the population of antibodies.

The present disclosure relates to a fusion protein of Z-domain and calsequestrin having improved reactivity, stability, and antibody recovery, and a method of isolating and purifying antibodies using the same. Specifically, the present disclosure relates to: a nucleic acid encoding a fusion protein of Z-domain and calsequestrin having improved reactivity, stability, and antibody recovery; a recombinant expression vector including the nucleic acid; a host cell transformed with the recombinant expression vector; and a method of isolating and purifying antibodies by using the fusion protein of Z-domain and calsequestrin having improved reactivity, stability, antibody recovery, and purity.

This disclosure relates to methods for the prevention of the reduction of disulfide bonds in a polypeptide expressed in a recombinant host cell, comprising, following fermentation, adding selenite and/or its salts or derivatives to a harvest solution of the recombinant host cell, wherein the disulfide bond in the polypeptide remains non-reduced.

Herein is reported a method for the final filtration of concentrated polypeptide solutions comprising the combination of two immediately consecutive filtration steps with a first filter of 3.0 μm and 0.8 μm pore size and a second filter of 0.45 μm and 0.22 μm pore size.

The present invention concerns a method of storing a separation matrix comprising multimers of immunoglobulin-binding alkali-stabilized Protein A domains covalently coupled to a porous support. The method comprises the steps of: a) providing a storage liquid comprising at least 50% by volume of an aqueous alkali metal hydroxide solution; b) permeating the separation matrix with the storage liquid; and c) storing the storage liquid-permeated separation matrix for a storage time of at least days. The alkali-stabilized Protein A domains comprise mutants of a parental Fc-binding domain of Staphylococcus Protein A (SpA), as defined by, or having at least 80% such as at least 90%, 95% or 98% identity to, SEQ ID NO 51 or SEQ ID NO 52, wherein the amino acid residues at positions 13 and 44 of SEQ ID NO 51 or 52 are asparagines and wherein at least the asparagine residue at position 3 of SEQ ID NO 51 or 52 has been mutated to an amino acid selected from the group consisting of glutamic acid, lysine, tyrosine, threonine, phenylalanine, leucine, isoleucine, tryptophan, methionine, valine, alanine, histidine and arginine.

An Fc-binding polypeptide of improved alkali stability, comprising a mutant of an Fc-binding domain of Staphylococcus Protein A (SpA), as defined by SEQ ID NO: 1, SEQ ID NO: 2, SEQ ID NO:3, SEQ ID NO: 4, SEQ ID NO: 5, SEQ ID NO:6, SEQ ID NO:7, SEQ ID NO:8, SEQ ID NO 26 or SEQ ID NO 27, wherein at least the alanine residue at the position corresponding to position 42 in SEQ ID NO:4-7 has been mutated to arginine and/or wherein at least the aspartic acid residue at the position corresponding to position 37 in SEQ ID NO:4-7 has been mutated to glutamic acid.

Provided are a method of efficiently producing an sIL-2R antigen in an amount necessary for antibody generation, and a method of producing an anti-sIL-2R antibody using the antigen. Specifically, provided are a method of producing soluble interleukin-2 receptor, including culturing SCC-3 cells and recovering soluble interleukin-2 receptor from a culture of the cells, and a method of producing an anti-soluble interleukin-2 receptor antibody, including immunizing an animal with sIL-2R produced by the method.

A mixed mode affinity chromatography carrier includes a substrate, a hydrophilic polymer, an antibody-binding cyclic peptide, and a cation exchange group.