A novel class of embryo derived peptides are described (Preimplantationfactor) that were generated synthetically and were tested on peripheral bloodimmune cells and shown to block activated but not basal immunity, inhibitingcell proliferation and creating a TH2 type cytokine bias, in addition PIFenhance endometrial receptivity by increasing adhesion molecules expression.PIF biological activity appears to be exerted by specific binding to induciblereceptors present on the several white cell lineages. PIF peptides, which areimmune modulators therefore may have diagnostic and non toxic therapeuticapplications in improving fertility, reducing pregnancy loss as well may beuseful when administered for the treatment of autoimmune diseases and forprevention xenotransplants rejection. Further, polyclonal antibodies againstPIF peptides were generated that serve for precise measurements of PIF inbiological fluids. They document pregnancy presence and viability as well ithelps for monitoring pregnancies at risk in humans as well as in farm and nonfarm animals, improving animal husbandry, where currently no specificpregnancy test exists. Also the PIF antibodies may have additional therapeuticproperties for treatment of HIV, and malaria.
