These results support the concept that soluble DPP4 might constitute a natural barrier against human infection that is more efficiently overcome by viruses currently circulating in Arabian camels than those in African camels.IMPORTANCEMiddle East respiratory syndrome coronavirus (MERS-CoV) is an emerging virus that can cause severe lung disease, MERS, and is transmitted from camels to humans. Here, DPP4 is linked to lung disorder.