Structural analysis of the oligosaccharides derived from glycodelin, a human glycoprotein with potent immunosuppressive and contraceptive activities

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 bearing 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.

Abnormal sperm morphology and other semen parameters related to the outcome of the hamster oocyte human sperm penetration assay

A new method for evaluation of sperm morphology using strict criteria is currently used in the andrology laboratory at the Eastern Virginia Medical School. A prospective study was designed to evaluate the following semen parameters in samples of all patients over a set period of time: sperm concentration and motility, and normal sperm morphology. These factors were correlated with results of the hamster zona-free oocyte/human sperm penetration assay (SPA). One hundred patients with a sperm concentration ranging from 2 to 219 X 10(6)/ml, a motile sperm fraction ranging from 6.9 to 87%, and normal sperm morphology ranging from 1 to 39%, were evaluated. The statistical analysis system general linear model was used to judge the influence of the different variables. There was a statistically significant relationship between the per cent of sperm with normal morphology and penetration rate in the SPA (P = 0.001). Outcome of the SPA was also correlated with in vitro fertilization, retrospectively, in 84 patients. Thirty-eight patients had an SPA less than 10%, with no fertilization in vitro in 13 patients (33.3%) and fertilization in 25 (66.7%). Forty-five had an SPA greater than 10% with fertilization in 37 (82.2%) and no fertilization in eight (17.8%) patients.