Detection using antisperm monoclonal antibodies of shared epitopes expressed by human spermatozoa and oocytes.
OBJECTIVE
To determine whether human spermatozoa and oocytes share common antigenic epitopes, supporting the hypothesis that their cross-linking by antisperm antibodies present in the clinical sera of infertile couples could promote sperm adhesion to the oolemma.


METHODS
Human and hamster eggs were studied for the presence of antigens recognized by a panel of World Health Organization Task Force monoclonal antibodies (mAbs) originally raised against human spermatozoa. A new technique was devised, using frozen sections of paraformaldehyde-fixed individual human and hamster eggs, to screen rapidly antisperm mAbs for egg reactivity. Living zona-free human and hamster eggs then were exposed to Covaspheres (Duke Scientific, Palo Alto, CA) coupled with these mAbs to document the presence of reactive epitopes on the oolemma.


METHODS
Academic research environment.


METHODS
Indirect immunofluorescence and Covasphere rosetting.


RESULTS
Eleven of 37 antisperm mAbs tested reacted with fixed hamster eggs and 10 reacted with human eggs. Five of 6 mAbs reactive with both fixed eggs also reacted with the oolemma of living, zona-free eggs.


CONCLUSIONS
Common antigenic epitopes, some of which are shared with somatic tissues, exist on the oolemma of human eggs and on the plasma membrane of human spermatozoa.
Fusi
F M
FM
Department of Obstetrics and Gynecology, Hospital San Rafaele, Milan, Italy.
Calzi
F
F
Ferrari
A
A
Bronson
R A
RA
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D006224:Cricetinae; D000939:Epitopes / Q000032:analysis / Q000276:immunology*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D008297:Male; D051379:Mice; D009865:Oocytes / Q000166:cytology / Q000276:immunology*; D013094:Spermatozoa / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes