Detection and Isolation of MCP (CD46) Protein in Human Seminal Plasma

MCP (membrane cofactor protein or CD46) is a complement regulatory proteins (CRPs), which is present in most of body cell membranes (except erythrocytes), and also in most biologycal body fliuds. Due to the important role of this protein in the complement system, specially in fertility, the aim of this study was to determine and isolate this protein in human seminal plasma. 6 semen samples which were considered normal according to W.H.O ceriteria were selected, and then seminal plasma of each sample was separated from sperms and debris by centrifugation. Prostasomes were obtained by ultracentrifugation from seminal plasma then the protein present in prostasome was isolated by FPLC cheromatoghraphy without using any detergent. The presence of MCP was determined by mAb (J4-48) againest CD46 using Dot blot technique. The molecular weight of CD46 was 55KD in first fraction at 6.5ml position by using SDS-PAGE. The presence of MCP in CSDS bound was proved using Western blot technique. Due to usage of such proteins (CD46) in clinical trials, such as infertility, this study shows that it is possible to isolate such proteins without introduction of detergents wich may change physiologycal functions of the protein.