Intrauterine Infusion of High Doses of Pig Trophoblast Interferons Has No Antiluteolytic Effect in Cyclic Gilts(2)
The situation appears clearer in domestic ruminants (sheep and cattle), in which the antiluteolytic factor, long known to be proteic , has been shown to be an interferon (IFN). IFNs are cytokines having antiviral, immunomodulatory, and antiproliferative activities. They comprise the multiple type I IFNs (containing several structurally related subfamilies) and a single type II IFN (or IFN–y), which is unrelated to the others. The ruminant antiluteolysins were identified as members of a specialized subfamily of type I IFNs, later named IFN-т, expressed in large amounts by the trophectoderm on Days 13-20 of pregnancy (reviewed in ).
Interestingly, we showed that during the corresponding period in the pig, the trophectoderm of the conceptus secretes two IFNs, which are, however, quite different from the ruminant IFN-т and have no known biological function. The major species is IFN–у (or type II IFN), which is expressed in amounts similar to those of IFN-т in ruminants. A type I IFN expressed in smaller amounts has recently been characterized. This IFN was provisionally named spl IFN (for short porcine type I IFN) and is the first member of a new family distantly related to all known type I IFNs including IFN-т. Recently it was officially designated as IFN-S. asthma inhalers
The lack of definitive identification of the primary signal involved in the maternal recognition of pregnancy in pigs raises the question of the possible involvement of pig trophoblastic IFNs in this phenomenon. In this paper, we determined whether intrauterine infusion of a mixture of both recombinant forms of pig trophoblastic IFNs into cyclic gilts could trigger antiluteolytic effects.
Tags: Interferons, Intrauterine Infusion, Pig, Trophoblast