| CPC G01N 33/6854 (2013.01) [B01D 15/168 (2013.01); B01D 15/3809 (2013.01); C07K 16/00 (2013.01); C07K 2317/52 (2013.01); C07K 2317/94 (2013.01)] | 4 Claims |
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1. A method for selecting a variant antibody of a parent antibody, comprising the steps of:
determining a first retention time of the variant antibody and the parent antibody on an FcRn affinity chromatography column with a positive linear pH gradient elution in the presence of a first salt concentration, and determining a second retention time of the variant antibody on an FcRn affinity chromatography column with the positive linear pH gradient elution in the presence of a second salt concentration, wherein:
the method is for selecting the variant antibody of the IgG1, IgG3 or IgG4 subclass that has a relative in vivo half-life that is increased compared to the parent antibody of the IgG1, IgG3 or IgG4 subclass, by selecting a variant antibody that has a first retention time that is longer than the first retention time of the parent antibody, and a first retention time that is substantially the same as the second retention time,
wherein the positive linear pH gradient is from about pH 5.5 to about pH 8.8; the salt is sodium chloride; and
wherein the first salt concentration is about 140 mM; and wherein the second salt concentration is about 400 mM.
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