Two-dimensional electrophoretic analysis of sperm antigens recognized by sperm immobilizing antibodies detected in infertile women

Abstract

In this study, high resolution two-dimensional (2-D) gel electrophoresis was used to identify human sperm antigens recognized by the sera from infertile women having sperm immobilizing (SI) antibodies. Two-D gel electrophoresis was employed to separate Percoll purified human sperm proteins using isoelectric focusing (IEF), followed by polyacrylamide gel electrophoresis (PAGE). Sperm proteins were transferred to the nitrocellulose membranes and immunoblotted with seven sera from infertile women with high titers of SI antibodies and 6 sera from those without SI antibodies. The blots were compared to the 2-D composite image of human sperm proteins [Sperm Protein Encyclopedia] and sperm surface index and the sperm surface proteins recognized by infertile sera were identified. Fifty-two human sperm surface proteins reacted with sera containing SI antibodies, while 35 of these were reactive with the SI-negative control sera. The average numbers of protein spots reacted with test and control sera were 24.6 and 15.0 respectively. A subset of sperm surface proteins which were unique to the SI antibodies were identified by the following criteria; the sperm protein spots which were highly reactive with the infertile sera containing SI antibodies but not reactive with any of the SI-negative infertile sera. The coordinates of 4 prominent immunoreactive sperm proteins were considered as possibly relevant to antibody mediated female infertility.