ABSTRACT
Tick-borne encephalitis virus (TBEV) causes tick-borne encephalitis (TBE), a severe and sometimes life-threatening disease characterized by viral invasion of the central nervous system with symptoms of neuroinflammation. As with other orthoflaviviruses-enveloped, arthropod-borne RNA viruses-host factors required for TBEV entry remain poorly defined. Here we used a genome-scale CRISPR-Cas9-based screen to identify LRP8, an apolipoprotein E and reelin receptor with high expression in the brain, as a TBEV receptor. LRP8 downregulation reduced TBEV infection in human cells, and its overexpression enhanced infection. LRP8 bound directly to the TBEV E glycoprotein and mediated viral attachment and internalization into cells. An LRP8-based soluble decoy blocked infection of human cell lines and neuronal cells and protected mice from lethal TBEV challenge. LRP8's role as a TBEV receptor has implications for TBEV neuropathogenesis and the development of antiviral countermeasures.
