The expression of the complement regulators CD46, CD55, and CD59 by human sperm does not protect them from antisperm antibody- and complement-mediated immune injury * †

摘要: Objectives To investigate whether membrane-bound regulators of the initial (C3) and terminal (C5b-9) complement (C) pathway components are expressed on human sperm to evaluate protective effects these in restricting antisperm antibody C-mediated injury. Design Sperm surface C inhibitors were quantitated by indirect immunofluorescence flow cytometry using murine monoclonal antibodies detect C3 regulatory proteins, C3b/C4b receptor type (CRI, CD35), membrane cofactor protein (CD46), decay-accelerating factor (CD55), C5b-9 inhibitor, P18 (CD59) acrosome-intact induced undergo acrosomal loss. The susceptibility antibody- immobilization was evaluated motility loss presence antidecay-accelerating and/or anti-P18. Setting University Oklahoma Health Sciences Center, a tertiary care referral center. Results Both detected loss; neither CR1. Membrane only acrosome-reacted sperm. time course antibody-negative sera factor, anti-P18, or both had cumulative effect brought about time-dependent enhancement serum C. However, C-fixing antibody-positive unaffected bound regulators. Conclusions C-induced may reflect low potency protein, inhibiting Therefore, use traditional assay for diagnosis cytotoxic infertile couples have limitations. inefficiency proteins activity also suggested secondary function localized proteolytic damage at site fertilization.