[Function of the spermatozoal plasma membrane in oocyte fertilization. Cell electrophoresis and immunofluorescence microscopy studies].

The influence of the capacitation on the electric charge of the spermatozoal surface and the unspecific spermatozoon-oocyte-binding are not fully understood up to now. Therefore, human semen samples were divided into two subgroups of spermatozoa by the "swim up" method. Both of the subgroups were examined by means of the micro-electrophoresis and the immunofluorescence technique using antihuman fibronectin antibodies. Cellular electrophoresis: The 2 subgroups of spermatozoa prepared of one semen sample showed a significantly different electrophoretic mobility (EPM) after washing and resuspension in an isotonic glycin-HCl-buffer (pH 2.0). In contrast, after resuspension in Baker's-buffer (pH 7.4) no difference between the 2 subgroups of one semen sample was detectable. The incubation in a medium with Ca++ caused secondly alterations of the EPM with the result of a smaller difference between the two subgroups of spermatozoa. Albumin also modified the EPM of spermatozoa. Immunofluorescence technique: 69 per cent of spermatozoa with a normal shape and only 17 per cent of them exhibiting a pathological shape showed a positive fibronectin-fluorescent-band on the equatorial segment called equatorial fibronectin band (EFB). Spermatozoa separated by "swim up" from semen samples with various semen parameters showed different percentages of spermatozoa with EFB. There was a significant difference between the spermatozoa of the two subgroups after "swim up" concerning EFB.