Group-specific component subtyping in semen and seminal stains by conventional isoelectric focusing

Group-specific component (GC) subtyping in semen and seminal stains was carried out using isoelectric focusing in carrier ampholyte-generated pH gradients and immunoblotting. In serum samples the anodal bands of GC 1F and of GC 1S disappeared by neuraminidase treatment, but in semen samples these bands remained unchanged after such treatment. The GC 2 type in semen exhibited two bands: the main GC 2 band and another fast band which focused at the position of the cathodic band of GC 1F. These seminal GC bands were unaffected by enzyme digestion. Reliable subtyping was possible in seminal stains stored at 4 degrees C for up to 10 weeks, at room temperature for up to 8 weeks, and at 37 degrees C for up to 5 weeks. The GC subtyping by conventional isoelectric focusing after neuraminidase treatment is simple, economical and useful in medicolegal examination of seminal stains.