Soluble Scavenger Receptor B2 (SCAB2) Trap is an Antiviral Agent for Hand, Foot, and Mouth Disease Viruses

Hand, foot, and mouth disease (HFMD) can show severe clinical symptoms in children and infants, such as fever, mouth ulcers, and vesicular rashes on the palms and feet.Enterovirus 71 (EV71) is the leading cause of this disease.In this study, we investigated the antiviral effect of soluble scavenger receptor type B2 (SCAB2, CD36) to develop a new therapeutic approach for HFMD.Soluble SCAB2: Fc was generated by using the human IgG1 Fc region.The SCAB2 gene was cloned into the expression plasmid with human IgG1 Fc sequences (SCAB2:Fc/PCK).SCAB2:Fc/PCK plasmid was transfected into HEK293T cells for 72 hours.Then the cell protein was extracted, and the culture supernatant was collected.The supernatant SCAB2:Fc protein was concentrated, and its concentration was measured using a human IgG1 ELISA kit.SCAB2:Fc strongly blocked the EV71 target cell entry in a dose-dependent manner.The antiviral activity of SCAB2:Fc was observed by western blot analysis and reverse transcription PCR (RT-PCR).VP1 capsid protein and virus-positive-strand RNA were significantly decreased in 100 ng/ml of SCAB2:Fc treatment.Transcription factor, eIF4G1, and cleaved caspases3 levels were reduced considerably with SCAB2:Fc treatment.Moreover, inhibiting virus infection strongly suppressed virus replication and cell proliferation regulating MAPK signaling.The phosphorylation of p38 and ERK1/2 was significantly decreased by SCAB2:Fc treatment.These data suggested that SCAB2:Fc inhibited EV71 infection and virus replication-induced MAPK signaling activity.In this study, the antiviral effect of soluble SCAB2 was investigated to develop an EV71 treatment.Soluble SCAB2:Fc showed potent antiviral activity in vitro, and it could be a potential candidate material to use as a therapeutic drug for EV71induced HFMD.