title: Testicular isoform of angiotensin I-converting enzyme (ACE, CD143) on the surface of human spermatozoa: revelation and quantification using monoclonal antibodies.
abstract: OBJECTIVE
  The elucidation of the role of angiotensin-converting enzyme (ACE, CD143) in the male fertility has been hampered by the absence of highly specific antibodies to the native testicular isoform (tACE). The quantification of tACE expression on human-ejaculated spermatozoa was performed using a novel panel of monoclonal antibodies (mAbs).
  
  
  METHODS
  The expression of tACE on the surface of live and fixed human spermatozoa was analyzed by flow cytometry and immunocytochemistry using new mAbs to human tACE.
  
  
  RESULTS
  Monoclonal antibodies 1E10 and 4E3 similarly revealed tACE on the surface of live and fixed spermatozoa. The high percentage of tACE-positive spermatozoa (median 81%) was revealed in the swim-up fraction of sperm. Antibody-induced tACE shedding occurs preferentially from live sperm with defective function and/or morphology. Testicular ACE is located on the plasma membrane of the post-acrosomal region, the neck and midpiece of normal spermatozoa, but showed a variable distribution on the defective cells.
  
  
  CONCLUSIONS
  The new mAbs recognizing the C-terminal domain of human ACE are useful tools for quantification of tACE expression on human live and fixed spermatozoa and further adequate analysis of the tACE role in reproduction.
authors.affiliation: Research Center for Obstetrics, Gynecology and Perinatology, Moscow, Russia.
authors.forename: Marina A
authors.initials: MA
authors.lastname: Nikolaeva
authors.forename: Irina V
authors.initials: IV
authors.lastname: Balyasnikova
authors.forename: Marina A
authors.initials: MA
authors.lastname: Alexinskaya
authors.forename: Roman
authors.initials: R
authors.lastname: Metzger
authors.forename: Folker E
authors.initials: FE
authors.lastname: Franke
authors.forename: Ronald F
authors.initials: RF
authors.lastname: Albrecht
authors.forename: Vladimir I
authors.initials: VI
authors.lastname: Kulakov
authors.forename: Gennady T
authors.initials: GT
authors.lastname: Sukhikh
authors.forename: Sergei M
authors.initials: SM
authors.lastname: Danilov
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D016466:CHO Cells; D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D006224:Cricetinae; D004542:Ejaculation; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D007703:Peptidyl-Dipeptidase A / Q000276:immunology / Q000378:metabolism*; D013081:Sperm Motility; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D000911:Antibodies, Monoclonal; C488034:ACE protein, human; D007703:Peptidyl-Dipeptidase A