[Effect on HLA-I expression in the presence of antisense oligonucleotides complementary to hepatitis B virus x gene]

In order to investigate inhibition of HLA-I expression by antisense oligonucleotides in vitro, three pieces of antisense phosphorothioate oligonucleotides (ASODN) complementary to hepatitis B virus (HBV) x gene key regions namely, 1510-1530, 1555-1581, 1768-1791 were synthesized. We also synthesized a SOND (sense strand) with same sequence of 1510-1530 as control. The specificity of inhibitory effect of the ASOND was determined using 2215 cell line by detection of HBxAg. In addition, we observed the inhibitory effect of ASODN on human HLA-I utilizing 2215 cells, the cells were stained with monoclonal antibody against human HLA-I heavy chain molecules, with fluorescenated sheep antimouse antibody as the second antibody and then analyzed on a EPICS profile II flow cytometer. HLA-I mRNA were assayed by in situ hybridization with a HLA-I heavy chain cDNA probe. The results indicated these ASODN could inhibit the expression of HBxAg, as well as HLA-I in cell surface. The result of 1 in situ hybridization showed that the decreased cell surface expression was correlated with steadily decreasing state of mRNA levels. The mechanism of action may be due to the inhibition of HBxAg by sequence specific ASODN, then resulting in decreasing of its transactivating effect on the HLA-I promoter.