Title : Structural analysis of
the oligosaccharides derived from
glycodelin , a human
glycoprotein with potent immunosuppressive and contraceptive activities
Abstract :
- Glycodelin , also known as placental protein 14 ( PP14 ) or progesterone-associated endometrial protein ( PAEP ), is a human glycoprotein with potent immunosuppressive and contraceptive activities
- In this paper we report the first characterization of glycodelin-derived oligosaccharides
- Using strategies based upon fast atom bombardment and electrospray mass spectrometry we have established that glycodelin is glycosylated at Asn-28 and Asn-63
- The Asn-28 site carries high mannose, hybrid and complex-type structures , whereas the second site is exclusively occupied by complex-type glycans
- The major non-reducing epitopes in the complex-type glycans are: Gal beta 1-4GlcNAc (lacNAc), GalNAc beta 1-4GlcNAc (lacdiNAc), NeuAc alpha 2-6Gal beta 1-4GlcNAc (sialylated lacNAc), NeuAc alpha 2-6Gal beta 1-4GlcNAc (sialylated lacdiNAc), Gal beta 1-4(Fuc alpha 1-3)GlcNAc (Lewisx), and GalNAc beta 1-4(Fuc alpha 1-3)GlcNAc (lacdiNAc analogue of Lewisx).
- It is possible that the oligosaccharides the oligosaccharides bearing sialylated lacNAc sialylated lacNAc or lacdiNAc antennae may manifest immunosuppressive effects by specifically blocking adhesive and activation-related events mediated by CD22 , the human B cell associated receptor
- Oligosaccharides with fucosylated lacdiNAc antennae have previously been shown to potently block selectin-mediated adhesions and may perform the same function in glycodelin
- The potent inhibitory effect of glycodelin on initial human sperm-zona pellucida binding is consistent with our previous suggestion that this cell adhesion event requires a selectin-like adhesion process
- This result also raises the possibility that a convergence between immune and gamete recognition processes may have occurred in the types of carbohydrate ligands recognized in the human