Role of Spermine in the Cytotoxic Effects of Seminal Plasma

Abstract
This report further characterizes the cytotoxic properties of seminal plasma and provides evidence for a role of spermine oxidation in the generation of seminal plasma cytotoxicity. Addition of spermine to lymphocyte cultures was found to result in a cytotoxic effect similar to that observed upon addition of seminal plasma. Furthermore, although seminal plasma is not cytotoxic in serum‐free medium, addition of monoamine oxidase was sufficient to result in the generation of seminal plasma‐associated cytotoxicity. Analysis of 73 individual seminal plasma samples indicated that all were cytotoxic, suggesting that this is an intrinsic property of seminal plasma. These results support a mechanism for seminal plasma cytotoxicity in which oxidation of spermine in seminal plasma by the amine oxidase of fetal calf serum results in generation of a cytotoxic product. It is hypothesized that this product plays a significant role in the phenomenon of seminal plasma immunosuppression. The general application of this principle to other fluids and tissues is discussed.