Recombinant Receptor Binding Domain Protein Induces Partial Protective Immunity in Rhesus Macaques Against Middle East Respiratory Syndrome Coronavirus Challenge()

Lan, Jiaming; Yao, Yanfeng; Deng, Yao; Chen, Hong; Lu, Guangwen; Wang, Wen; Bao, Linlin; Deng, Wei; Wei, Qiang; Gao, George F.; Qin, Chuan; Tan, Wenjie

The Middle East respiratory syndrome coronavirus (MERS-CoV) is the only lineage C betacoronavirus known to infect humans (Annan et al., 2013; Anthony et al., 2013; van Boheemen et al., 2012) . Similarly to severe acute respiratory syndrome coronavirus (SARS-CoV), MERS-CoV infection can result in acute respiratory distress syndrome and organ dysfunction, including progressive renal function impairment . According to the World Health Organization, by the end of 12 August 2015, a total of 1401 cases had been laboratory confirmed, with at least 500 deaths following MERS-CoV infection. Among them, 186 MERS-CoV infection cases, including 36 deaths, had been reported by the Republic of Korea (http://www.who.int/csr/don/12-august-2015mers-saudi-arabia/en/). These recent clustered cases firstly sprang up outside the Arabian Peninsula, indicating the potential human-tohuman transmission of MERS-CoV. To date, no specific antiviral drug exists for MERS-CoV infection and supportive treatment is the mainstay of management (Zumla et al., 2015) . Ribavirin and interferon alfa-2b exhibited potential in a rhesus macaque model (Falzarano et al., 2013a, b) , but in a retrospective cohort study, ribavirin and interferon alfa-2a therapy was associated with significantly improved survival at 14 days, but not at 28 days in patients with severe MERS-CoV infection (Omrani et al., 2014) . Besides, specific peptide fusion inhibitors of MERS-CoV , convalescent sera from recovered patient and human monoclonal neutralising antibodies Tang et al., 2014; Ying et al., 2014) provided a novel approach to MERS-CoV treatment. However, more data are needed from animal studies and carefully done clinical studies (Zumla et al., 2015) . Therefore, developing a prophylactic vaccine against MERS-CoV infection remains a priority (Papaneri et al., 2015) .