[Early immunosuppression and implantation]

In this brief review, we recall the antigenic status of the embryo and the possible threats that the maternal immune system poses to fetal survival even at implantation stage. We then quickly recall the existence of Early Pregnancy Factor (EPF), the available data for early embryo derived suppressor and suppressor inducer molecules, point to the existence of cloned progesterone dependent T cell derived suppressor molecule, disquisite on immunoregulatory properties of tau interferons, and finish by dealing with Interleukin 10 and the TH1/TH2 balance concept.