The effect of oxidative environment on immunosuppressive properties of human seminal plasma

Problem: Human seminal plasma (SP) has an important immunosuppressive function that enables sperm survival in the female reproductive tract. The aim of this study was to evaluate how oxidized proteins, by oxidative stress, may influence seminal plasma immunosuppressive properties in male infertility. Method of study: Human SP immunosuppressive ability was evaluated by a lymphocyte proliferation assay. We used phytohemagglutinin mitogen to induce lymphocyte proliferation in the presence of human SP from infertile and fertile men, and under in vitro oxidizing conditions. Human SP-oxidized proteins (MDA-protein) were determined by the thiobarbituric acid test. Results: Significant high levels of oxidized proteins were found in SP from asthenozoospermic patients. There was a significant difference (P < 0.05) between lymphocyte proliferation in the presence of SP from normozoospermic and asthenozoospermic group compared to the fertile donor group. Oxidized human SP in vitro allows for higher lymphocyte proliferation than non-oxidized SP. Conclusion: Human SP proteins have an inhibitory ability on lymphocyte proliferation, but under oxidative stress conditions, these proteins lose their immunosuppressive function. © 2008 The Authors Journal compilation © 2008 Blackwell Munksgaard.