Human IgG1 antibodies suppress angiogenesis in a target-independent manner.

Sasha Bogdanovich (1) , Younghee Kim (1) , Takeshi Mizutani (1, 2) , Reo Yasuma (1) , Laura Tudisco (3) , Valeria Cicatiello (3, 4) , Ana Bastos-Carvalho (1) , Nagaraj Kerur (1) , Yoshio Hirano (1) , Judit Z Baffi (1) , Valeria Tarallo (1, 3) , Shengjian Li (1) , Tetsuhiro Yasuma (1, 2) , Parthasarathy Arpitha (1) , Benjamin J Fowler (1) , Charles B Wright (1) , Ivana Apicella (3) , Adelaide Greco (5, 6) , Arturo Brunetti (5, 6) , Menotti Ruvo (7) , Annamaria Sandomenico (7) , Miho Nozaki (2) , Ryo Ijima (2) , Hiroki Kaneko (2) , Yuichiro Ogura (2) , Hiroko Terasaki (2) , Balamurali K Ambati (8, 9) , Jeanette Hw Leusen (10) , Wallace y Langdon (11) , Michael R Clark (12) , Kathryn L Armour , Pierre Bruhns (13) , J Sjef Verbeek (14) , Bradley D Gelfand (1) , Sandro de Falco (3, 15) , Jayakrishna Ambati (1)

1 UK - University of Kentucky
2 Nagoya City University [Nagoya, Japan]
3 IGB-CNR - Institute of Genetics and Biophysics - “Adriano Buzzati-Traverso” [Naples, Italy]
4 BIO-KER (Multimedica Group) [Naples]
5 University of Naples Federico II = Università degli studi di Napoli Federico II
6 CEINGE - Biotecnologie Avanzate
7 CNR – Istituto di Biostrutture e Bioimmagini
8 University of Utah School of Medicine [Salt Lake City]
9 Salt Lake City Veterans Affairs Health Care System
10 University Medical Center [Utrecht]
11 UWA - The University of Western Australia
12 CAM - University of Cambridge [UK]
13 Anticorps en thérapie et pathologie - Antibodies in Therapy and Pathology
14 Leiden University Medical Center (LUMC)
15 IRCCS Multimedica

Aberrant angiogenesis is implicated in diseases affecting nearly 10% of the world's population. The most widely used anti-angiogenic drug is bevacizumab, a humanized IgG1 monoclonal antibody that targets human VEGFA. Although bevacizumab does not recognize mouse Vegfa, it inhibits angiogenesis in mice. Here we show bevacizumab suppressed angiogenesis in three mouse models not via Vegfa blockade but rather Fc-mediated signaling through FcγRI (CD64) and c-Cbl, impairing macrophage migration. Other approved humanized or human IgG1 antibodies without mouse targets (adalimumab, alemtuzumab, ofatumumab, omalizumab, palivizumab and tocilizumab), mouse IgG2a, and overexpression of human IgG1-Fc or mouse IgG2a-Fc, also inhibited angiogenesis in wild-type and FcγR humanized mice. This anti-angiogenic effect was abolished by Fcgr1 ablation or knockdown, Fc cleavage, IgG-Fc inhibition, disruption of Fc-FcγR interaction, or elimination of FcRγ-initated signaling. Furthermore, bevacizumab's Fc region potentiated its anti-angiogenic activity in humanized VEGFA mice. Finally, mice deficient in FcγRI exhibited increased developmental and pathological angiogenesis. These findings reveal an unexpected anti-angiogenic function for FcγRI and a potentially concerning off-target effect of hIgG1 therapies.

Domains: Immunology

Sasha Bogdanovich, Younghee Kim, Takeshi Mizutani, Reo Yasuma, Laura Tudisco, et al.. Human IgG1 antibodies suppress angiogenesis in a target-independent manner.. Signal Transduction and Targeted Therapy, 2016, 1, pp.15001. ⟨10.1038/sigtrans.2015.1⟩. ⟨pasteur-02511158⟩