comparison of cd46 concentration of seminal plasma in fertile and infertile men

introduction: membrane cofactor protein (mcp or cd46) is one of the regulatory of complement system. it is present in all somatic cells except in rbc. it is also present in all body fluids and semen. the aim of this study was measuring the concentration of this protein in semen of fertile and infertile individuals and to study the relationship between the concentration of this protein and semen parameters. materials and methods: the man concentration of cd46 was measured by sandwich eliza in 8 normospermic, 22 asthenopsermic, 22 oligo-asthenospermic and 11 azoospermic individuals. in this technique one monoclonal antibody used for capture and another monoclonal antibody againts cd46 was used for detection. a polycolonal antibody conjugated to hrp was used for staining. pearson correlation and t-test was used for statistical analysis. results: the man concentrations were 710, 453, 582 and 639 ng/ml for normospermic, asthenospermic, oligo-asthenospermic and azoo sperm individuals-respectively. the pearson correlation showed a signification correlation between cd46 concentration with sperm motility (r=+0.59 & p<0.001), sperm viability (r=+0.53 & p<0.005) and sperm concentration (r=-0.37 & p<0.003). conclusions: previous reports suggest no difference between cd46 concentration between fertile and infertile individuals. however our results showed that the level of cd46 significantly reduces in asthenospermic and hyperspermic (>200 million/ml) individuals. the correlation between sperm motility and sperm concentration with cd46 suggests that cd46 might influence sperm motility and this molecule appears to be taken up by spermatozoa. reduction in cd46 might predispose to become astheno, oligo or oligo-astheno-spermic.