[Identification and initial characterization of a protease of immunoglobulin A associated with human spermatozoa]

The factors that the human semen use to block the humoral immune response at the uterine cervix level are not known. This response is mainly represented by immunoglobulin A, secretory type (IgAs). A possible mechanism would be hydrolisis od IgAs in an analogue ways as it has been described for some pathogenous bacteria that colonized human epitheliums and hydrolize IgAs. The objective of this study was to search for the presence of a protease for IgAs in human semen, seminal plasma and espermatozoons, using immunoelectrophoresis in agarose and electrophoresis in polyachrilamide, doing after immunotransference in nitrocellulose membrane. It was possible to identify a protease in sepermatic fraction, that hydrolizes IgAs, producing two fragments, the first one with molecular weight 66 to 70 kD, the degrees C. It is a metaloprotease (inhibited by EDTA). Its acti-enzymatic activity was optimal at 24 hours, pH 7.5 at 37 C. It is a metaloprotease (inhibited by EDTA). Its activity was specific for IgAs, and do not affected other immunoglobulins (IgG and IgM). The enzymatic activity of spermatozoon demonstrated in this study, may be on of the necessary factors used for blocking humoral immune response in femenine genital tract, and to permit that spermatozoon achieve the fecundation of human ovocyte.