Tolerance Signaling Molecules and Pregnancy: IDO, Galectins, and the Renaissance of Regulatory T Cells

Authors


Prof. David A. Clark, Department of Medicine, McMaster University Rm. 3V39, 1200 Main St. West, Hamilton, ON, Canada L8N 3Z5.
E-mail: clarkd@mcmaster.ca

Abstract

Problem  Is the concept of maternal tolerance preventing rejection of the semi-allogeneic ‘fetal allograft’ still valid?

Method of study  Compilation of expert reviews of literature and recent advances in research on indoleamine-2,3 dioxygenase (IDO), regulatory T cells and galectin-1.

Results and Conclusion  A role for IDO in pregnancy success remains speculative, but solid data exist to support a role for Treg cells, and for galectin-1 in induction and action of Treg cells. Just as several signals may need to be simultaneously present to induce Th1 cytokine-triggered abortions, more than 1 signal may need to be simultaneously present to prevent rejection and ensure success. Both complement and coagulation pathways appear necessary for embryo execution.

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