A sialoglycoprotein, gp20, of the human capacitated sperm surface is a homologue of the leukocyte CD52 antigen: analysis of the effect of anti-CD52 monoclonal antibody (CAMPATH-1) on capacitated spermatozoa.
In this study we performed N-terminal sequence analysis of gp20, a 20 kDa sialoglycoprotein on the human sperm surface previously identified by radiolabelling of the sialic acid residues of sperm surface. We found 100% identity with the N-terminus of CD52, an antigen expressed on almost all human leukocytes. We also show that, like CD52, gp20 behaves as a glycosylphosphatidylinositol (GPI)-anchored protein and that anti-gp20 antiserum reacts with an antigen on leukocytes of the same molecular weight as CD52. Using CAMPATH-1, the monoclonal antibody against CD52, in fluorescent staining of capacitated spermatozoa, Western blot analysis and the zona-free hamster egg penetration test, we found that the effect of this antibody was different from that of our anti-gp20. Western blot analysis revealed a well-defined 20 kDa band with anti-gp20, whereas a 14-20 kDa band was detected with CAMPATH-1. Anti-gp20 stained the equatorial region of the sperm head, whereas CAMPATH-1 stained the tail in immunofluorescence analysis of capacitated spermatozoa. A dose-dependent inhibitory effect was seen with CAMPATH-1, similar to that previously detected with anti-gp20, in a zona-free hamster egg penetration test. However, with CAMPATH-1 agglutination of motile spermatozoa was detected, and this was not present with anti-gp20. This suggests that the epitopes recognized by the two antibodies are different.
Department of Evolutionary Biology, University of Siena, Italy.
R
R
Focarelli
S
S
Francavilla
F
F
Francavilla
C
C
Della Giovampaola
A
A
Santucci
F
F
Rosati
D000328:Adult; D000074323:Alemtuzumab; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm / Q000494:pharmacology*; D015703:Antigens, CD / Q000276:immunology*; D000951:Antigens, Neoplasm; D015153:Blotting, Western; D000074301:CD52 Antigen; D006224:Cricetinae; D005260:Female; D005453:Fluorescence; D006023:Glycoproteins / Q000276:immunology*; D017261:Glycosylphosphatidylinositols / Q000378:metabolism; D006801:Humans; D007962:Leukocytes / Q000276:immunology; D008297:Male; D009865:Oocytes / Q000502:physiology; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid; D012795:Sialoglycoproteins / Q000737:chemistry / Q000378:metabolism*; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000187:drug effects / Q000502:physiology*; D015044:Zona Pellucida
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000912:Antibodies, Neoplasm; D015703:Antigens, CD; D000951:Antigens, Neoplasm; D000074301:CD52 Antigen; C000613862:CD52 protein, human; D006023:Glycoproteins; D017261:Glycosylphosphatidylinositols; D012795:Sialoglycoproteins; C118578:gp20 sialoglycoprotein, human; D000074323:Alemtuzumab