Expression of gp20, a human sperm antigen of epididymal origin, is reduced in spermatozoa from subfertile men

Abstract

ABSTRACTgp20, a sialylglycoprotein of human sperm homologous to CD52, is present everywhere on the surface of the freshly ejaculated sperm but is prevalently localized in the equatorial region of the head of capacitated sperm. In the present study, we confirmed this feature on large scale and correlated equatorial exposure of the antigen to the presence of serum albumin (SA) in the capacitation medium. Furthermore, we analyzed the relationship between the presence of the antigen and its equatorial exposure after capacitation and fertility, by comparing immunostaining for gp20 in the motile fraction of spermatozoa from fertile and subfertile men. A significantly higher percentage of nonimmunostained spermatozoa before capacitation (38.5% AE 23 vs. 12% AE 7, P < 0.0001) and a lower increase in the percentage of sperm with equatorial localization after capacitation (19.3% AE 25 vs. 34.6% AE 22, P ¼ 0.039) were observed in subfertile men (n ¼ 60) compared to fertile men (n ¼ 15). In the whole study group, a positive correlation was also found between the percentage of spermatozoa exhibiting equatorial localization in capacitated samples and normal head forms (R ¼ 0.50; P < 0.0001). Mol. Reprod. Dev. 69: 235-240, 2004. ß 2004

Beta-Defensin 126 on the Cell Surface Protects Sperm from Immunorecognition and Binding of Anti-Sperm Antibodies1

“…DEFB126 is a b-defensin which appears to be unique among sperm surface coating proteins, in that it uniformly spans the entire sperm surface and is not exclusive to a specific domain [23]. CD52 has also been reported to coat the whole sperm, but there is an elevated presence over the equatorial segment and variable labeling depending on where the sperm resided in the male reproductive tract and the state of capacitation [14,24,25]. The question of whether the uniform distribution of 1 DEFB126 on the macaque sperm surface can serve as an immunoprotective shield was initially proposed by Tollner et al [20] and is the focus of this study.…”

Sperm preparation: state-of-the-art—physiological aspects and application of advanced sperm preparation methods

“…116 The level of expression of this protein on spermatozoa appears to be positively correlated with the percentage of normal morphological forms in the same sperm cell as well as with the state of sperm capacitation and status of male fertility. 117,118 Based on this negative electrical charge, it is possible to separate spermatozoa by means of the so-called (i) zeta potential and (ii) electrophoretic technique.…”

Methods for Sperm Selection for In Vitro Fertilization

“…These observations and the fact that CD52 is correlated with normal sperm morphology and capacitation (Giuliani et al, 2004), may account for the ability of the electrophoresis separation method to select sperm with significantly improved morphology with low levels of DNA damage (Ainsworth et al, 2005). Key futures of the electrophoresis system that make it attractive for ART laboratories are: the whole process of selection can take only a few minutes and the generation of ROS is minimized because of lack of centrifugation steps.…”