Download MendeleyXenopus IgX informs engineering strategies of IgM and IgG hexamers.
Zhang, R., Ji, C., Li, S., Li, N., Gao, N., Xiao, J.(2025) Sci Adv 11: eaea3737-eaea3737
- PubMed: 41191733
- DOI: https://doi.org/10.1126/sciadv.aea3737
- Primary Citation of Related Structures:
9UO3, 9UO4, 9UO5, 9UO6 - PubMed Abstract:
Polymeric immunoglobulins are essential components of the immune system in jawed vertebrates. While mammalian immunoglobulin M (IgM) typically forms a pentamer linked by the joining chain (J-chain), Xenopus laevis IgX can assemble into a J-chain-independent polymer. Here, we present the cryo-electron microscopy (cryo-EM) structure of IgX, revealing its hexameric configuration. By incorporating the IgX tailpiece into human IgM, we achieved efficient IgM hexamer formation. Truncating IgM's natural tailpiece to a range of 11 to 16 residues also substantially enhanced hexamerization efficiency. Furthermore, introducing a shortened IgM tailpiece to IgG resulted in effective IgG hexamer formation. We further show that the engineered IgM and IgG hexamers targeting CD20 demonstrated robust complement-dependent cytotoxicity (CDC) against several B lymphoma cells. In addition, the IgG-Fc hexamer functioned as a decoy, attenuating CDC in cell cultures. These findings deepen our understanding of polymeric immunoglobulin evolution and introduce innovative strategies for the development of IgM- and IgG-based biologics.
- Biomedical Pioneering Innovation Center (BIOPIC), State Key Laboratory of Gene Function and Modulation Research, School of Life Sciences, Peking University, Beijing, P.R. China.
Organizational Affiliation:
