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

One week after the final immunisation, animals were transferred to an ABSL-3 laboratory. Following an adaptive phase of 1 week, nine immunised monkeys were anaesthetised and inoculated intratracheally with MERS-CoV of the hCoV-EMC strain at a dosage of 6.5 × 10 7 TCID 50 , diluted in 1-mL DMEM. After the challenge with MERS-CoV, monkeys were observed twice daily, with detailed recording of clinical signs and symptoms, morbidity and mortality, including the nature, onset, severity and duration of all gross or visible changes. Chest X-rays were performed 1 day pre-and 1 and 3 days post-inoculation (dpi) with MERS-CoV. Nasal, oropharyngeal and rectal swabs were collected at the same time points. Three days after challenge with MERS-CoV, monkeys were euthanized and tissue specimens, including lungs, trachea, spleen and kidney, were collected for various pathological, virological, and immunological tests. The schematic of the vaccination schedule and biological specimen collection timeline are displayed in Fig. 1 .