CD81 sequence and susceptibility to hepatitis C infection

Area of Science:

• Virology
• Genetics
• Immunology

Background:

• Cell surface molecules like CD81 may act as receptors for hepatitis C virus (HCV) entry.
• The large extracellular loop (LEL) of CD81 binds the HCV envelope protein E2 at critical residues.
• Genetic variations in the CD81 LEL could potentially influence HCV infection susceptibility.

Purpose of the Study:

• To investigate if variations in the CD81 LEL gene sequence affect susceptibility to HCV infection or disease outcome.
• To compare CD81 LEL sequences in patients with spontaneous viral clearance, chronic infection, and those exposed but uninfected.

Main Methods:

• Genomic DNA and cDNA from peripheral blood mononuclear cells were extracted from HCV RNA negative, RNA positive, and exposed uninfected patients.
• Four exons of the CD81 LEL gene were amplified and sequenced.
• Specific DNA sections (A, B, C, D) and the entire CD81 cDNA sequence were analyzed for variations.

Main Results:

• No sequence differences were observed in the CD81 LEL gene, including the critical E2 binding region, across all patient groups.
• Analysis of both genomic DNA and cDNA revealed a highly conserved nucleotide sequence for the CD81 LEL.
• No evidence of gene methylation that could influence HCV infection was found.

Conclusions:

• The large extracellular loop of CD81 is highly conserved and does not appear to harbor sequence variations that influence susceptibility or outcome of HCV infection.
• Genetic variations within the CD81 LEL are unlikely to be a significant factor in determining HCV infection status or clearance.