Objective: To study the influence and mechanism of HBV core region mutation on HLA-I expression.
Methods: Eukaryotic expression vectors of HBV core region mutations L97, G87 and V60 were constructed and transfected into HepG2 cells. Then the expressions of HLA-I were detected by RT-PCR and Western blot. The mRNA of antigen-presentation-associated genes, including LMP2, TAP1 and tapasin, were measured using RT-PCR.
Results: Different levels of HBsAg in the supernatants of transfected cells were detected by ELISA. The HBsAg of the mutated groups was markedly higher than that of the wild ones. All the transfected cells expressed HLA-I molecules, especially the L97 group. It was also found that the mRNA of TAP1 gene was up-regulated, while the mRNA of LMP and tapasin genes had no changes.
Conclusion: The core region mutation of HBV can lower the expression of HBsAg; mutated groups and wild ones both can increase the expression of HLA-I molecules. The up-regulation of TAP1 gene expression might be the cause of these changes.