Reactivities of a monoclonal antibody directed against an immunosuppressive molecule in boar seminal plasma

Using a monoclonal antibody (LIS-4) to an immunosuppressive factor isolated from boar vesicular gland secretion it was determined that this gland secretes a tissue-specific immunosuppressive molecule that is absorbed onto the acrosome of spermatozoa during ejaculation. Absorption of the immunosuppressive molecule onto murine embryos at the 2-, 4-, 8-cell, morula and blastocyst stages in vitro was evaluated by indirect immunofluorescence. In vivo absorption was detected on the zona pellucida of murine embryos obtained from oviducts injected with the immunosuppressive molecule. Immunofluorescence revealed that the immunosuppressive molecule was not absorbed onto murine embryos after solubilization of the zona pellucida. There was no effect of the antibody to the immunosuppressive molecule on the ability of boar spermatozoa to penetrate the porcine zona pellucida.