Interaction between hTIM-1 and Envelope Protein Is Important for JEV Infection

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Japanese encephalitis virus (JEV) is a major cause of viral encephalitis transmitted by mosquitoes.
• Host cell entry co-factors, like human TIM-1 (hTIM-1), are crucial for JEV infection.
• Previous studies identified hTIM-1 as a phosphatidylserine (PS) binding factor promoting JEV entry, but the direct interaction mechanism remained unclear.

Purpose of the Study:

• To elucidate the direct interaction between hTIM-1 and JEV.
• To identify specific binding sites involved in the hTIM-1 and JEV interaction.
• To explore therapeutic strategies targeting the hTIM-1-JEV interaction.

Main Methods:

• Co-immunoprecipitation assays to confirm direct interaction.
• Site-directed mutagenesis to identify binding interfaces.
• Confocal microscopy to track co-internalization and intracellular transport.
• In vitro infection assays using soluble hTIM-1 protein and hTIM-1 antibodies.

Main Results:

• Demonstrated direct binding between hTIM-1 and the JEV E protein.
• Identified specific binding sites: ND114115 on hTIM-1 and K38 on JEV E protein.
• Showed co-internalization of hTIM-1 and JEV into endosomes during early infection.
• Confirmed that soluble hTIM-1 protein inhibits JEV infection in vitro.
• Demonstrated that hTIM-1 antibodies reduce JEV infectivity.

Conclusions:

• hTIM-1 directly interacts with the JEV E protein via specific binding sites, mediating viral entry.
• This direct interaction is a key mechanism for JEV infection, independent of the previously known PS-TIM-1 interaction.
• Targeting the hTIM-1-JEV E protein interaction, using soluble proteins or antibodies, presents a promising therapeutic avenue against Japanese encephalitis.