乙型肝炎e抗原对外周血单核细胞Toll样受体2表达的影响

The influence of hepatitis B e antigen on the expression of toll-like receptor 2 on peripheral monocytes

目的探讨HBeAg对外周血单核细胞表面Toll样受体2（TLR2）表达的影响。方法对68例慢性乙型肝炎（CHB）患者（其中HBeAg与HBVDNA阳性37例，HBeAg阴性、HBVDNA阳性14例，HBeAg与HBVDNA阴性17例）和16名健康人的外周血肝素抗凝，加入Pam3CSK4在37℃、5％CO2条件下刺激3h，用特异性TLR2单克隆抗体标记，经流式细胞仪检测CD14＋’细胞表面TLR2表达的百分率；比较刺激前后各组之间的差异。定量检测HBVDNA和血清HBV标志物，分析TLR2表达水平与HBeAg、HBV DNA的关系。用HBeAg与健康人及HBeAg阴性CHB患者的抗凝血在37℃、5％CO2条件下共培养6h，用流式细胞仪定量分析HBeAg刺激后CD14＋细胞表面TLR2的表达水平。结果HBeAg阳性CHB患者外周血CD14＋细胞TLR2的表达率为47．57％±21．40％，明显低于健康对照组（76．51％±7．46％）和HBeAg阴性组（HBVDNA阳性组为73．2％±14．2％、HBVDNA阴性组为75．2％±11．3％，P〈0．05）；TLR2的表达水平在HBeAg阴性的HBVDNA阳性或阴性CHB患者组与健康对照组的差异无统计学意义。HBeAg阳性CHB患者外周血单核细胞经Pam3CSK4刺激后，TLR2的表达率明显升高，大部分患者TLR2的表达水平能够达到健康人或HBeAg阴性患者未经配体刺激的水平。健康人或HBeAg阴性CHB患者的外周血与HBeAg共孵育6h后，CD14＋细胞表面TLR2表达水平较HBeAg刺激前明显下降（P〈0．05）。结论HBeAg阳性的CHB患者外周血CD14＋细胞TLR2的表达水平明显低于HBeAg阴性患者和健康人，HBeAg能够抑制CD14＋细胞TLR2的表达，提示HBeAg能够引起CHB患者外周血单核细胞表面TLR2表达的下调，这可能是HBV持续感染的重要因素之一；CHB患者HBVDNA水平可能不影响单核细胞表面TLR2的表达；Pam3CSK4可以明显提高HBeAg阳性CHB患者单核细胞表面TLR2的表达水平，TLR2配体有可能成为CHB免疫治疗的一个潜在靶位。

Objective In order to investigate the relationship among the toll-like receptor 2 （TLR2）, hepatitis B e antigen and HBV DNA, the expression levels of TLR2 on peripheral blood monocytes of chronic hepatitis B （CHB） patients as well as on their monocytes stimulated by ligand of TLR2 （Pam3CSK4） and HBeAg were analyzed. Methnds Sixty-eight adults with CHB were enrolled, including 37 HBeAg-positive patients, 17 HBeAg-negative and HBV DNA negative patients, and 14 HBeAg-negative and HBV DNA positive patients. Sixteen healthy volunteers were also studied as controls. TLR2 expression levels on their peripheral blood monocytes stimulated with Pam3CSK4 or not stimulated were analyzed by FACS Calibur. The relationship of the expression levels of TLR2, HBeAg and HBV DNA were also analyzed. The level of TLR2 on peripheral blood monocytes of healthy volunteers and HBeAg-negative CHB patients stimulated by HBeAg was examined for six hours. Results The TLR2 expression levels on CD14＋ cells were significantly reduced in I-IBeAg-positive patients （47.57% ± 21.40 %） compared to both healthy volunteers （76.51% ± 7.46%） and HBeAg-negative patients （HBV DNA positive group 73.2%± 14.2%, HBV DNA negative group 75.2% ± 11.3%）; but there was no difference between those of the HBeAg-negative patients and the healthy volunteers. Expression levels of TLR2 on monocytes stimulated by TLR2 ligand in HBeAg-positive patients were obviously increased, and reached the basic levels of the healthy volunteers and the HBeAg-negative patients. The expression levels of TLR2 on monocytes stimulated by HBeAg of the healthy volunteers and the HBeAg-negative patients were markedly reduced. Conclusions In the presence of HBeAg, HBV down- regulates the expressions of TLR2 on CD14＋ cells from peripheral blood, and there is no correlation between HBV-DNA and TLR2. Pam3CSK4 can boost the TLR2 expression in HBeAg-positive patients. The pro- posed interaction between HBV and TLR2 may provide an important clue to explain the reasons of the establishment of persistent HBV infection.