Transient pentameric IgM fulfill biological function-Effect of expression host and transfection on IgM properties

• Published in: PloS one Vol. 15; no. 3; p. e0229992
• Main Authors: Hennicke, Julia, Schwaigerlehner, Linda, Grünwald-Gruber, Clemens, Bally, Isabelle, Ling, Wai Li, Thielens, Nicole, Reiser, Jean-Baptiste, Kunert, Renate
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 12.03.2020; Public Library of Science (PLoS)
• Subjects: Antibodies; Antigens; Biochemistry, Molecular Biology; Biological effects; Biology and Life Sciences; Biotechnology; Comparative analysis; Complement; Complement activation; Cytomegalovirus; Dihydrofolate reductase; Electron microscopy; Genes; Glycan; Glycosylation; Immunoglobulin M; Life Sciences; Mediation; Medicine and Health Sciences; Microscopy; Natural resources; Physical Sciences; Polymers; Post-translation; Production management; Proteins; Quality management; Research and analysis methods; Structural Biology; Structural integrity; Structure-function relationships; Transfection; Transmission electron microscopy; Workflow; Workflow software; France; Austria
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0229992

Recombinant production of IgM antibodies poses a special challenge due to the complex structure of the proteins and their not yet fully elucidated interactions with the immune effector proteins, especially the complement system. In this study, we present transient expression of IgM antibodies (IgM617, IgM012 and IgM012_GL) in HEK cells and compared it to the well-established stable expression system in CHO cells. The presented workflow investigates quality attributes including productivity, polymer distribution, glycosylation, antibody structure and activation of the classical complement pathway. The HEK293E transient expression system is able to generate comparable amounts and polymer distribution as IgM stably produced in CHO. Although the glycan profile generated by HEK293E cells contained a lower degree of sialylation and a higher portion of oligomannose structures, the potency to activate the complement cascade was maintained. Electron microscopy also confirmed the structural integrity of IgM pentamers produced in HEK293E cells, since the conventional star-shaped structure is observed. From our studies, we conclude that the transient expression system provides an attractive alternative for rapid, efficient and high-throughput production of complex IgM antibodies with slightly altered post-translational modifications, but comparable structure and function.