TY - JOUR
T1 - Sialylation of human IgG-Fc carbohydrate by transfected rat alpha2,6- sialyltransferase
AU - Jassal, R
AU - Jenkins, N
AU - Charlwood, J
AU - Camilleri, P
AU - Jefferis, Royston
AU - Lund, John
PY - 2001/8/17
Y1 - 2001/8/17
N2 - A recombinant IgG3 antibody with Phe-243 replaced by Ala (FA243) was expressed in a CHO-K1 parental cell line. The resulting IgG-Fc-linked carbohydrate was significantly alpha2,3-sialylated (53% of glycans), as indicated by normal- and reverse-phase HPLC analyses. Following transfection of a rat alpha2,6-sialyltransferase gene into this parental cell line, IgG-Fc-linked glycans were sialylated (60% of glycans) such that the ratio of alpha2,6- to alpha2,3-linked sialic acid was 0.9:1.0. By comparison, the wild-type IgG3 (F243) is minimally sialylated (2-3% alpha2,3-linked), thus suggesting that sialylation is controlled primarily by the protein structure local to the carbohydrate and that the two sialyltransferases compete to sialylate the nascent oligosaccharide. The additional alpha2,6-sialylation affected the function of the recombinant antibody. FA243 IgG3 having both alpha2,6 and alpha2,3-sialylation restored recognition to wild-type IgG3 levels for human FcgammaRI, FcgammaRII, and target cell lysis by complement. We discuss how sialylation linkage could modulate IgG function.
AB - A recombinant IgG3 antibody with Phe-243 replaced by Ala (FA243) was expressed in a CHO-K1 parental cell line. The resulting IgG-Fc-linked carbohydrate was significantly alpha2,3-sialylated (53% of glycans), as indicated by normal- and reverse-phase HPLC analyses. Following transfection of a rat alpha2,6-sialyltransferase gene into this parental cell line, IgG-Fc-linked glycans were sialylated (60% of glycans) such that the ratio of alpha2,6- to alpha2,3-linked sialic acid was 0.9:1.0. By comparison, the wild-type IgG3 (F243) is minimally sialylated (2-3% alpha2,3-linked), thus suggesting that sialylation is controlled primarily by the protein structure local to the carbohydrate and that the two sialyltransferases compete to sialylate the nascent oligosaccharide. The additional alpha2,6-sialylation affected the function of the recombinant antibody. FA243 IgG3 having both alpha2,6 and alpha2,3-sialylation restored recognition to wild-type IgG3 levels for human FcgammaRI, FcgammaRII, and target cell lysis by complement. We discuss how sialylation linkage could modulate IgG function.
KW - glycosylation
KW - complement
KW - sialylation
KW - Fc gamma receptors
KW - IgG
UR - http://www.scopus.com/inward/record.url?scp=0034815962&partnerID=8YFLogxK
U2 - 10.1006/bbrc.2001.5382
DO - 10.1006/bbrc.2001.5382
M3 - Article
C2 - 11500028
VL - 286
SP - 243
EP - 249
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 2
ER -