Pathogenesis Study of Enterovirus 71 Using a Novel Human SCARB2 Knock-In Mouse Model

Enterovirus 71 (EV71) can cause a severe hand-foot-mouth disease in children. However, the precise mechanism of EV71-associated disease, particularly the neuropathogenesis and pulmonary disorder, is still not fully understood because no suitable animal models are available. The human scavenger receptor class B, member 2 (hSCARB2), is a cellular receptor for EV71. Here, we generated a novel knock-in (KI) mouse model using the CRISPR/Cas9 system to insert the hSCARB2 gene into the mouse Rosa26 locus to study the pathogenesis of EV71. The hSCARB2 KI mice infected with clinical isolates of EV71 showed neurological symptoms, such as ataxia, paralysis, and death. Viral replication was detected in mainly astrocytes and a limited number of neurons and microglia, accompanied by gliosis. Vascular leakage and alveoli filled with erythrocytes were detected, suggesting that edema and hemorrhage, which are observed in human patients, also occurred in EV71-infected KI mice. In addition, proinflammatory cytokines and chemokines were significantly increased in the serum of infected KI mice. These pathological features of the KI mice after infection resembled those of EV71 encephalomyelitis in humans. Therefore, our KI mouse model is suitable to study the pathogenesis of EV71 and is of great significance for development of antiviral drugs and vaccines to treat or prevent EV71 infection. IMPORTANCE Enterovirus 71 (EV71) is associated with severe hand-foot-mouth disease. Recently, outbreaks of EV71 infection with high mortality have been reported in the Asia-Pacific region, posing a great challenge for global public health. To date, the precise mechanism of EV71-induced disease, particularly the neuropathogenesis and respiratory disorders, is still not fully understood because no suitable animal models are available. Human scavenger receptor class B, member 2 (hSCARB2), has been identified as a cellular receptor for EV71. Here, we introduce a novel CRISPR/Cas9-mediated hSCARB2 knock-in (KI) mouse model for the study of EV71 pathogenesis, which is of great significance for the development of antiviral drugs and vaccines.