Membrane attack complex (MAC)-mediated damage to spermatozoa: protection of the cells by the presence on their membranes of MAC inhibitory proteins.
Although antibody and complement are known to cause immobilization and killing of spermatozoa in vitro the components of the complement system mediating these effects remain undefined. Here we have examined the effects of the membrane attack complex (MAC) on spermatozoa and demonstrate that spermatotoxic effects are dependent on assembly of the complete MAC. We subsequently examined the presence and functional significance of the complement regulatory proteins decay accelerating factor (DAF), MAC-inhibiting protein (MIP) and CD59 antigen on spermatozoa. Both DAF and CD59 antigen were present on the membranes of these cells. Neutralization of CD59 antigen with specific antibodies increased the susceptibility of the cells to MAC-mediated damage, suggesting a role for this molecule in the protection of spermatozoa from complement-mediated damage in the female reproductive tract.
Rooney
I A
IA
Department of Medical Biochemistry, University of Wales College of Medicine, Cardiff, U.K.
Davies
A
A
Morgan
B P
BP
D015703:Antigens, CD / Q000032:analysis; D018958:CD55 Antigens; D018957:CD59 Antigens; D002470:Cell Survival / Q000276:immunology; D015938:Complement Membrane Attack Complex / Q000037:antagonists & inhibitors / Q000276:immunology*; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D006801:Humans; D007248:Infertility, Male / Q000276:immunology; D008297:Male; D008562:Membrane Glycoproteins / Q000032:analysis; D008565:Membrane Proteins / Q000032:analysis; D011506:Proteins / Q000032:analysis*; D013081:Sperm Motility / Q000502:physiology*; D013094:Spermatozoa / Q000276:immunology*
D015703:Antigens, CD; D018958:CD55 Antigens; D018957:CD59 Antigens; D015938:Complement Membrane Attack Complex; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D011506:Proteins