Towards a solution to MERS: protective human monoclonal antibodies targeting different domains and functions of the MERS-coronavirus spike glycoprotein

Widjaja, Ivy; Wang, Chunyan; van Haperen, Rien; Gutiérrez-Álvarez, Javier; van Dieren, Brenda; Okba, Nisreen M.A.; Raj, V. Stalin; Li, Wentao; Fernandez-Delgado, Raul; Grosveld, Frank; van Kuppeveld, Frank J. M.; Haagmans, Bart L.; Enjuanes, Luis; Drabek, Dubravka; Bosch, Berend-Jan

The Middle-East respiratory syndrome coronavirus (MERS-CoV) is a zoonotic virus that causes severe and often fatal respiratory disease in humans. Efforts to develop antibody-based therapies have focused on neutralizing antibodies that target the receptor binding domain of the viral spike protein thereby blocking receptor binding. Here, we developed a set of human monoclonal antibodies that target functionally distinct domains of the MERS-CoV spike protein. These antibodies belong to six distinct epitope groups and interfere with the three critical entry functions of the MERS-CoV spike protein: sialic acid binding, receptor binding and membrane fusion. Passive immunization with potently as well as with poorly neutralizing antibodies protected mice from lethal MERS-CoV challenge. Collectively, these antibodies offer new ways to gain humoral protection in humans against the emerging MERS-CoV by targeting different spike protein epitopes and functions.