Regulatory T cells in pregnancy.

Area of Science:

• Immunology
• Reproductive Biology
• Maternal-Fetal Medicine

Background:

• Maternal-fetal tolerance is essential for successful pregnancy, preventing immune attack on the semi-allogeneic fetus.
• Regulatory T cells (Treg) are implicated in maintaining this tolerance, particularly towards fetal alloantigens.
• Reduced Treg numbers have been linked to pregnancy complications like fetal rejection and miscarriage.

Purpose of the Study:

• To investigate the role of Regulatory T cells (Treg) in maintaining maternal-fetal tolerance.
• To explore the therapeutic potential of Treg cell transfer in preventing pregnancy loss.
• To elucidate the mechanisms underlying Treg-mediated tolerance during pregnancy.

Main Methods:

• Adoptive transfer of CD4(+)/CD25(+) Treg cells from pregnant mice into abortion-prone animal models.
• Analysis of Treg cell numbers and function during normal and complicated pregnancies.
• Measurement of key immunosuppressive factors (TGF-beta, LIF, HO-1) in the uterine microenvironment.

Main Results:

• Adoptive transfer of Treg cells prevented abortion in susceptible animals.
• Treg cell transfer established a transient tolerant microenvironment with elevated TGF-beta, LIF, and HO-1.
• Diminished Treg cell levels were observed in cases of fetal immunological rejection and human miscarriage.
• Evidence suggests Treg activation by male antigens is necessary for protective function.

Conclusions:

• Regulatory T cells (Treg) play a critical role in preventing maternal immune rejection of the fetus.
• Treg cell therapy holds promise for preventing pregnancy loss associated with immune dysregulation.
• The protective function of Treg cells during pregnancy may depend on activation by paternal antigens.