Characterization of spermatozoa surface antigens by antisperm antibodies and its influence on acrosomal exocytosis.
OBJECTIVE
Antisperm antibodies (ASA) are the main cause of immunological infertility, they impair sperm functions by binding to the sperm membrane. The aim of this study was to characterize highly enriched sperm membrane proteins by 2-D-electrophoresis and to identify membrane antigens binding ASA and to evaluate the influence of ASA on the acrosome reaction (AR).


METHODS
Sperm membrane proteins were separated by 2-D-electrophoresis and antigens were identified by immunoblotting with ASA from seminal plasma samples of infertile men. The influence of ASA on the AR were observed and determined by means of flowcytometry.


RESULTS
A total of 18 antigens were identified by using ASA from seminal plasma. Six of the recognized proteins were analyzed by means of mass spectrometry and peptide matching: HSP70 and HSP70-2, disulfide-isomerase-ER60, caspase-3 and two subunits of the proteasome (component-C2 and zeta-chain). ASA from seminal plasma are able to enhance the AR in donor-spermatozoa.


CONCLUSIONS
The biochemical identification of these proteins will be helpful to understand the mechanism by which ASA impair sperm function and the fertilization process. Spermatozoa, in which the AR was prematurely induced by ASA, will not be able to fertilize anymore.
Bohring
Claudia
C
Department of Andrology, Clinical Training Center of the European Academy of Andrology, University Hospital Marburg, Germany. bohring@mailer.uni-marburg.de
Krause
Walter
W
D020101:Acrosome Reaction / Q000276:immunology*; D000941:Antigens / Q000276:immunology / Q000302:isolation & purification*; D000954:Antigens, Surface / Q000276:immunology; D001323:Autoantibodies / Q000276:immunology / Q000302:isolation & purification*; D015153:Blotting, Western; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D005089:Exocytosis / Q000276:immunology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D007248:Infertility, Male / Q000276:immunology; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism; D046988:Proteasome Endopeptidase Complex; D019704:Protein Disulfide-Isomerases / Q000378:metabolism; D012661:Semen / Q000276:immunology; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013094:Spermatozoa / Q000737:chemistry / Q000276:immunology*
D000941:Antigens; D000954:Antigens, Surface; D001323:Autoantibodies; D018840:HSP70 Heat-Shock Proteins; D009097:Multienzyme Complexes; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D019704:Protein Disulfide-Isomerases