Conformation of the Human Immunoglobulin G2 Hinge Imparts Superagonistic Properties to Immunostimulatory Anticancer Antibodies

• Published in: Cancer cell 2015-01, Vol.27 (1), p.138-148
• Main Authors: White, Ann L., Chan, H.T. Claude, French, Ruth R., Willoughby, Jane, Mockridge, C. Ian, Roghanian, Ali, Penfold, Christine A., Booth, Steven G., Dodhy, Ali, Polak, Marta E., Potter, Elizabeth A., Ardern-Jones, Michael R., Verbeek, J. Sjef, Johnson, Peter W.M., Al-Shamkhani, Aymen, Cragg, Mark S., Beers, Stephen A., Glennie, Martin J.
• Format: Article
• Language: English
• Subjects: Animals; Antibodies, Monoclonal - chemistry; Antibodies, Monoclonal - immunology; Antibodies, Monoclonal - therapeutic use; CD28 Antigens - immunology; CD40 Antigens - immunology; Cells, Cultured; Humans; Immunoglobulin G - chemistry; Immunoglobulin G - immunology; Immunoglobulin G - therapeutic use; Mice; Mice, Inbred C57BL; Receptors, IgG - immunology; Thymoma - drug therapy; Thymoma - immunology; Thymoma - prevention & control; Thymus Neoplasms - drug therapy; Thymus Neoplasms - immunology; Thymus Neoplasms - prevention & control; Tumor Necrosis Factor Receptor Superfamily, Member 9 - immunology; Vaccination - methods
• ISSN: 1535-6108; 1878-3686
• DOI: 10.1016/j.ccell.2014.11.001

Monoclonal antibody (mAb) drugs that stimulate antitumor immunity are transforming cancer treatment but require optimization for maximum clinical impact. Here, we show that, unlike other immunoglobulin isotypes, human IgG2 (h2) imparts FcγR-independent agonistic activity to immune-stimulatory mAbs such as anti-CD40, -4-1BB, and -CD28. Activity is provided by a subfraction of h2, h2B, that is structurally constrained due its unique arrangement of hinge region disulfide bonds. Agonistic activity can be transferred from h2 to h1 by swapping their hinge and CH1 domains, and substitution of key hinge and CH1 cysteines generates homogenous h2 variants with distinct agonistic properties. This provides the exciting opportunity to engineer clinical reagents with defined therapeutic activity regardless of FcγR expression levels in the local microenvironment. •Immunomodulatory mAbs are revolutionizing cancer treatment but need optimization•Agonistic mAbs are generally dependent on FcγR crosslinking for activity•An unusual disulfide hinge configuration in human IgG2 is superagonistic•IgG2 engineering provides therapeutics that are active in tissues devoid of FcγR White et al. find that human IgG2 antibodies are superagonistic due to a unique disulfide hinge configuration and do not require FcγR crosslinking for activity. These findings will facilitate optimization of immunomodulatory antibodies for cancer treatment.