An antibody produced in tobacco expressing a hybrid beta-1,4-galactosyltransferase is essentially devoid of plant carbohydrate epitopes.
N-glycosylation of a mAb may have a major impact on its therapeutic merits. Here, we demonstrate that expression of a hybrid enzyme (called xylGalT), consisting of the N-terminal domain of Arabidopsis thaliana xylosyltransferase and the catalytic domain of human beta-1,4-galactosyltransferase I (GalT), in tobacco causes a sharp reduction of N-glycans with potentially immunogenic core-bound xylose (Xyl) and fucose (Fuc) residues as shown by Western blot and MALDI-TOF MS analysis. A radioallergosorbent test inhibition assay with proteins purified from leaves of WT and these transgenic tobacco plants using sera from allergic patients suggests a significant reduction of potential immunogenicity of xylGalT proteins. A mAb purified from leaves of plants expressing xylGalT displayed an N-glycan profile that featured high levels of galactose, undetectable xylose, and a trace of fucose. Hence, a transgenic plant expressing the hybrid GalT might yield more effective and safer monoclonals for therapeutic purposes than WT plants and even transgenic plants expressing the unchanged GalT.
Bakker
Hans
H
Business Unit Bioscience, Plant Research International, Wageningen University and Research Center, Droevendaalsesteeg 1, 6708 PB, Wageningen, The Netherlands.
Rouwendal
Gerard J A
GJ
Karnoup
Anton S
AS
Florack
Dion E A
DE
Stoopen
Geert M
GM
Helsper
Johannes P F G
JP
van Ree
Ronald
R
van Die
Irma
I
Bosch
Dirk
D