Sialylation of human IgG-Fc carbohydrate by transfected rat alpha2,6- sialyltransferase

Research output: Contribution to journalArticle


  • R Jassal
  • N Jenkins
  • J Charlwood
  • P Camilleri

Colleges, School and Institutes


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.


Original languageEnglish
Pages (from-to)243-9
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - 17 Aug 2001


  • glycosylation, complement, sialylation, Fc gamma receptors, IgG