Patent ID: 8440191

Claim:
An isolated antibody polypeptide which specifically binds IgA1, said polypeptide comprising one or both of (a) a naturally occurring or non-naturally occurring serine or threonine residue at the end of a CH1 domain, which serine or threonine residue has been artificially modified by addition of an O-linked glycan, and (b) a naturally occurring or non-naturally occurring asparagine residue at the end of a CH1 domain, which asparagine residue has been artificially modified by addition of an N-linked glycan; (i) wherein the O-linked glycan has the following formula: wherein, (Ser/Thr) is one of said one or more non-naturally occurring serine or threonine residues which has been modified by the addition of said O-linked glycan, wherein S.A. is a sialic acid, wherein, R 1 is H, (GalNAc) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and wherein R 2 is H or S.A; and (ii) wherein the N-linked glycan has a formula selected from the group consisting: (a) wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan, wherein S.A. is a sialic acid; wherein, R 1 is H, (GlcNAc) n , where n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, and wherein R 2 is H or S.A; or (b) a biantennary structure having the formula: wherein (Asn) is one of said one or more non-naturally occurring asparagine residues which has been modified by the addition of said N-linked glycan, wherein S.A. is a sialic acid, wherein R 1 is H, (GlcNAc) n , or (GlcNAc) n linked to mannose, wherein n =1, 2, 3, 4, 5, 6, 7, 8, 9, or 10, wherein R 2 is H, mannose, (GlcNAc) n , or mannose linked to (GlcNAc) n , wherein n=1, 2, 3, 4, 5, 6, 7, 8, 9, or 10.