Identification of cell membrane proteins that bind visna virus

Area of Science:

• Virology
• Immunology
• Cell Biology

Background:

• Visna virus, a lentivirus, infects ovine cells via its envelope glycoprotein binding to a cell surface receptor.
• The specific identity of the visna virus receptor has remained unknown, hindering understanding of viral tropism and pathogenesis.

Purpose of the Study:

• To identify the specific cell surface molecule(s) responsible for visna virus attachment and entry into host cells.
• To characterize the molecular weight and binding properties of potential visna virus receptors on ovine cells.

Main Methods:

• Virus overlay protein blot assays were employed to detect cell surface molecules binding to purified visna virus.
• Affinity purification using radiolabeled cell membrane preparations was performed to isolate virus-binding proteins.
• Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) was used to determine the molecular masses of purified proteins.
• Immunofluorescence assays and virus-binding inhibition assays were conducted using antibodies against identified proteins.

Main Results:

• Visna virus bound to cell surface molecules of approximately 15, 30, and 50 kDa on goat synovial membrane (GSM) and sheep choroid plexus (SCP) cells.
• Antibodies against the 50 kDa protein demonstrated binding to the surface of live GSM and SCP cells.
• Antibodies against the 50 kDa protein successfully blocked visna virus binding to SCP cells, while antibodies to 15 and 30 kDa proteins did not.

Conclusions:

• The 50 kDa protein is identified as the primary cell surface receptor for visna virus on ovine target cells.
• This finding elucidates the molecular mechanism of visna virus cell entry and provides a target for potential therapeutic interventions.