Immune effector functions of human IgG2 antibodies against EGFR

Thies Rösner, Steffen Kahle, Francesca Montenegro, Hanke L Matlung, J H Marco Jansen, Mitchell Evers, Frank Beurskens, Jeanette H W Leusen, Timo K van den Berg, Thomas Valerius

Research output: Contribution to journalArticleAcademicpeer-review


Three FDA approved epidermal growth factor receptor (EGFR) antibodies (Cetuximab, Panitumumab, Necitumumab) are clinically available to treat patients with different types of cancer. Interestingly, Panitumumab is of human IgG2 isotype, which is often considered to have limited immune effector functions. Unexpectedly, our studies unraveled that human IgG2 antibodies against EGFR mediated effective CDC when combined with another non cross-blocking EGFR antibody. This second antibody could be of human IgG1 or IgG2 isotype. Furthermore, EGFR antibodies of human IgG2 isotype were highly potent in recruiting myeloid effector cells such as M1 macrophages and PMN for tumor cell killing by ADCC. Tumor cell killing by PMN was more effective with IgG2 than with IgG1 antibodies if tumor cells expressed lower levels of EGFR. Additionally, lower expression levels of the "don't eat me" molecule CD47 on tumor cells enabeled ADCC also by M2 macrophages, and improved PMN and macrophage mediated ADCC. A TCGA enquiry revealed broadly varying CD47 expression levels across different solid tumor types. Together, these results demonstrate that human IgG2 antibodies against EGFR can promote significant Fc mediated effector functions, which may contribute to their clinical efficacy. The future challenge will be to identify clinical situations in which myeloid effector cells can optimally contribute to antibody efficacy.

Original languageEnglish
Pages (from-to)75-88
Number of pages14
JournalMolecular Cancer Therapeutics
Issue number1
Early online date3 Oct 2018
Publication statusPublished - Jan 2019

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