The effects of hepatitis B e antigen on Toll-like receptor 9 and CD8 activated costimulatory molecules expressions on human peripheral blood mononuclear cells

Objective To investigate the effects of hepatitis B e antigen (HBeAg) on expressions of Toll-like receptor 9 (TLR9), CD83 and programmed cell death ligand-1 (PD-L1) on CD14+ monocytes and surface expressions of CD107a and CD107b on CD8+ T lymphocytes in human peripheral blood mononuclear cells (PBMC). Methods Twenty healthy subjects were strictly selected from the physical examination. PBMC of these subjects were collected. Restructuring HBeAg incubation was set as stimulated group, and complete medium incubation as control group. The expressions of CD83 and PD-L1 on CD14+ cells, and those of CD107a and CD107b on CD8+ T lymphocyte in both groups were detected by flow cytometry. TLR9 mRNA expression was detected by reverse transcriptase-polymerase chain reaction. Student t test was used for statistical analysis. Results After stimulated with 10 μg/mL of restructuring HBeAg for 12 h, TLR9 mRNA expression level was 0.362±0.021, which was significantly lower than control group (0.519±0.032, t=-7.62, P 0.05). CD107b expression ([1.59±1.06]% vs [2.03±1.18]%, t=1.21, P>0.05) in stimulated group was lower than those in control group, while the difference between the two groups did not reach statistical significance. The expressions of CD107 ([1.28±0.73]% vs [1.87±0.59]%, t=2.82, P<0.05) and CD107a ([5.73±2.15]% vs [7.77±2.31]%, t=2.90, P<0.05) on CD8+ T lymphocyte surface in stimulated group were significantly lower than those in control group. Conclusion HBeAg may suppress innate immune system and adaptive immune response by increasing PD-L1 expression on CD14+ cells, while decreasing the expressions of TLR9, CD83 on CD14+ cells and 107a, CD107b on CD8+ T lymphocyte. Key words: Hepatitis B e antigens; Peripheral blood mononuclear cells; Toll-like receptor 9; Costimulatory molecules; Lysosomal-associated membrane protein