MERS coronaviruses from camels in Africa exhibit region-dependent genetic diversity

Chu, Daniel K. W.; Hui, Kenrie P. Y.; Perera, Ranawaka A. P. M.; Miguel, Eve; Niemeyer, Daniela; Zhao, Jincun; Channappanavar, Rudragouda; Dudas, Gytis; Oladipo, Jamiu O.; Traoré, Amadou; Fassi-Fihri, Ouafaa; Ali, Abraham; Demissié, Getnet F.; Muth, Doreen; Chan, Michael C. W.; Nicholls, John M.; Meyerholz, David K.; Kuranga, Sulyman A.; Mamo, Gezahegne; Zhou, Ziqi; So, Ray T. Y.; Hemida, Maged G.; Webby, Richard J.; Roger, Francois; Rambaut, Andrew; Poon, Leo L. M.; Perlman, Stanley; Drosten, Christian; Chevalier, Veronique; Peiris, Malik

We successfully isolated representative clade C1 viruses from West Africa (BF785 from Burkina Faso and Nig1657 from Nigeria) for phenotypic characterization in comparison with human clade A (strain EMC) virus and a camel clade B (AH13) virus from Saudi Arabia. BF785 has the most extensive deletion of the ORF4b gene product, with loss of the whole PDE domain as well as the nuclear-localizing signal, while Nig1657 retains the nuclear-localizing domain and part of its PDE domain, although the PDE catalytic site is lost. Compared with EMC and AH13, both BF785 and Nig1657 viruses had significantly reduced replication competence in Calu-3 cells as assessed by titration of infectious virus at 24 and 48 h post infection at MOIs of 0.01 and 0.1, respectively. In contrast, we had previously demonstrated that the East African dromedary/Egypt-NRCE-HKU-270/2013 had comparable or better replication competence than EMC and AH13 viruses in Calu-3 cells (15) . Compared with EMC and AH13, the BF785 virus also had reduced replication competence in vivo in the The cell-culture supernatants were tested for IP-10 protein using the BD Cytometric bead-assay (detection limit 7.54 pg/mL). The experiment was carried out with three biological replicates. Statistical significance was determined by two-way ANOVA with Bonferroni's correction and is indicated as *P < 0.05; **P < 0.01; ***P < 0.001.