Recombinant plant-derived human IgE glycoproteomics

Area of Science:

• Biotechnology
• Immunology
• Glycoscience

Background:

• Human immunoglobulin E (IgE) is crucial in biotechnology, but its complex N-glycosylation poses expression challenges.
• Understanding IgE glycosylation is vital for its therapeutic applications, yet knowledge remains limited.

Purpose of the Study:

• To express recombinant human IgE in glycan-engineered and wild-type *Nicotiana benthamiana* plants.
• To perform in-depth N-glycosylation analysis of plant-derived IgE.
• To investigate the impact of glycoengineering on IgE glycosylation homogeneity and explore potential structure-function relationships.

Main Methods:

• Recombinant IgE expression in *Nicotiana benthamiana* (wild-type and glycan-engineered strains).
• Mass spectrometric profiling for N-glycosylation analysis.
• Computational modeling to assess glycan spatial effects.

Main Results:

• Plant-derived IgE exhibited site-specific N-glycosylation, with varying occupancy rates across different glycosites (GS1-7).
• Complex N-glycans were found at GS1-5 and oligomannosidic structures at GS7, similar to human IgE.
• Glycoengineered plants produced IgE with homogeneous GnGn structures, while wild-type plants produced GnGnXF structures, contrasting with the high diversity of HEK cell-derived IgE.
• Computational modeling suggested that glycan orientation can influence processing and occupancy at adjacent sites.

Conclusions:

• Plant-based expression systems can be engineered to control recombinant IgE glycosylation, achieving high homogeneity.
• This controlled glycosylation is a significant advancement for studying carbohydrate-dependent IgE functions.
• The ability to tailor IgE glycosylation opens avenues for producing therapeutic IgE with optimized properties.