BALB/c mice; hDPP4-Tg mice; Rabbits  Elicits MERS-CoV S1 and RBD-specific Abs in mice (IgG (> 1:105), IgG1, and IgG2a) and rabbits (IgG), neutralizing 17 pseudotyped (≥ 1:104) and 2 live (≥ 1:103) MERS-CoV (EMC2012 and London1-2012 strains)  Induces MERS-CoV S1-specific cellular immune responses (IFN-γ and IL-2) in mice  Protects vaccinated Ad5/hDPP4-transduced BALB/c mice and majority (4/6) of vaccinated hDPP4-Tg mice from MERS-CoV (EMC2012 strain, 105 PFU for BALB/c; 103–4 TCID50 for Tg) challenge, without immunological toxicity or eosinophilic immune enhancement  Du et al., 2013a; Ma et al., 2014b; Tang et al., 2015; Zhang et al., 2016; Nyon et al., 2018