Monomeric I g A can be produced in planta as efficient as I g G , yet receives different N ‐glycans

The unique features of I g A , such as the ability to recruit neutrophils and suppress the inflammatory responses mediated by I g G and I g E , make it a promising antibody isotype for several therapeutic applications. However, in contrast to I g G , reports on plant production of I g A are scarce. We produced I g A 1κ and I g G 1κ versions of three therapeutic antibodies directed against pro‐inflammatory cytokines in N icotiana benthamiana : I nfliximab and A dalimumab, directed against TNF ‐α, and U stekinumab, directed against the interleukin‐12p40 subunit. We evaluated antibody yield, quality and N ‐glycosylation. All six antibodies had comparable levels of expression between 3.5 and 9% of total soluble protein content and were shown to have neutralizing activity in a cell‐based assay. However, I g A 1κ‐based A dalimumab and U stekinumab were poorly secreted compared to their I g G counterparts. Infliximab was poorly secreted regardless of isotype backbone. This corresponded with the observation that both I g A 1κ‐ and I g G 1κ‐based I nfliximab were enriched in oligomannose‐type N ‐glycan structures. For I g G 1κ‐based U stekinumab and A dalimumab, the major N ‐glycan type was the typical plant complex N ‐glycan, biantennary with terminal N ‐acetylglucosamine, β1,2‐xylose and core α1,3‐fucose. In contrast, the major N ‐glycan on the I g A ‐based antibodies was xylosylated, but lacked core α1,3‐fucose and one terminal N ‐acetylglucosamine. This type of N ‐glycan occurs usually in marginal percentages in plants and was never shown to be the main fraction of a plant‐produced recombinant protein. Our data demonstrate that the antibody isotype may have a profound influence on the type of N ‐glycan an antibody receives.