Evaluation of sperm specific lactate dehydrogenase isoenzyme C4 (LDH C4)--application to semen detection in stains.

The usefulness of LDH C (or LDH X) as a semen-specific marker has been tested. Many different methods have been applied for identification using various electrophoretic methods such as agarose gel electrophoresis, IEF, rocket-immunoelectrophoresis with subsequent enzymatical, immunological and immunochemical detection methods. Further methods applied were dot blot analysis for LDH C and PCR analysis for X/Y-chromosome differentiation. In blood/semen mixtures the LDH C-bands were detectable in dilutions up to 50-fold after staining for total LDH activity. An appropriate extraction procedure was developed. Immunological tests using a polyclonal antibody against LDH C were found to be highly specific and highly sensitive. The immunological test gave positive results with azoospermic stains up to a few weeks and in normal sperm stains positive reactions were obtained even after 8 months storage. A comparison of different detection methods for semen showed that immunological detection methods for LDH C are, at least after longer time periods of storage, superior to microscopical detection. Swabs showed positive LDH C-reactions up to 48 h after intercourse. This reaction was closely correlated to PCR for male cells and to microscopical searching.