2.1. Materials

Three healthy rhesus macaques (one‐year‐old, two males and 1 female) with no any infection were obtained from the Institute of Medical Biology, Chinese Academy of Medical Sciences and Peking Union Medical College (animal permit number: SCXK (DIAN) K2015‐0004). The euthanasia procedure was performed according to the rules for euthanasia of experimental animals (http://www.lascn.net/), the Guide for the Care and Use of Laboratory Animals, 10 and the ARRIVE Guidelines for Reporting Animal Research. 11 This experiment was reviewed and approved by the Animal Ethical and Welfare Committee of Kunming Medical University.