Abstract: Objective To study the expression of Toll-like receptors (TLRs) mRNA in human trophoblast HTR-8/SVneo cells and
the changes in indoleamine 2,3-dioxygenase (IDO) mRNA expression in response to TLR ligand stimulation. Methods The
expressions of TLRs and IDO mRNA in human HTR-8/SVneo cells were tested by RT-PCR, and the changes in IDO mRNA
levels after exposure to TLR3, TLR4, TLR7/8, and TLR9 ligands were quantitatively analyzed with real-time PCR. Results
IDO and TLR1-10 mRNAs were expressed in HTR-8/SVneo cells. As the cell culture time extended, IDO mRNA expression
level tended to increase within 48 h. After stimulation with the TLR ligands, the expression of TLR-3 mRNA was
down-regulated while the expression of TLR-4, 7, 8, and 9 mRNA up-regulated. Stimulation of the cells with poly(I:C) lowered
the expression of IDO mRNA while IFN-γ increased its expression. Conclusions The expression of IDO mRNA is associated
with the nutrition of the maternal-fetal interface. Stimulation with the TLR ligands affects the expression of IDO and TLR
mRNA expressions in the cells, which verifies the functional activity of TLRs and suggests a role of IDO in TLR
pathway-dependent antiviral immunity.