Abstract: Abstract Objective：To study on the distribution of toll-like receptor 3 (TLR3) in human placenta and their role in the HBV intrauterine infection. Methods：Twenty two full-term placental tissues of HBsAg carriers and 6 ones of HBsAg sero-negative pregnant women were collected. The HBsAg and TLR3 in the placental tissues were investigated by StreptAnidin-Biotin peroxidase Complex (SABC) immunohistochemical staining. Neonatal HBsAg and HBeAg was tested by Chemiluminescence. HBsAg in maternal sera were detected by ELISA. Results：The HBsAg positive rate in the full-time placental tissues from HBsAg carrier pregnant women was 77.27% (17/22). The positive signals of HBsAg could locate in the cytoplasms of decidual cells, trophoblastic cells, villous meseachymal cells and villous capillary endothelial cells. The positive signals of TLR3 major locate in the cytoplasm of trophoblastic cells and villous meseachymal cells in the HBsAg-positive placental tissues. TLR3 could not be found in the placenta of HBsAg sero-negative pregnant women. Conclusion: Preliminary considering, there may be only weak response of TLR3 to HBV stimulation.

Key words: toll-like receptor 3, hepatitis B virus, intrauterine infection, placenta