Effects of sperm-immobilizing antibodies on sperm-zona pellucida tight binding.
OBJECTIVE
To evaluate the in vitro effects of sperm-immobilizing antibodies on sperm-zona pellucida (ZP) tight binding.


METHODS
The hemizona assay (HZA) was used to study the inhibitory effects of infertile women's sera with and without sperm-immobilizing antibodies on sperm ZP tight binding. These results were compared with those of monoclonal sperm-immobilizing antibodies.


METHODS
The patients were collected from a university hospital infertility clinic.


METHODS
Sera from 40 infertile women (24 with and 16 without sperm-immobilizing antibodies) and 2 postpartum women as control were used.


RESULTS
Of 24 patients' sera with sperm-immobilizing antibodies, 23 (96%) showed significant inhibitory effect, whereas none of 16 patient's sera without sperm-immobilizing antibodies exhibited any inhibitory effect. However, there was no correlation between the antibody titers of sperm-immobilizing antibody and the hemizona index. Among four monoclonal sperm-immobilizing antibodies tested, only one showed a significant inhibitory effect on the sperm-zona tight binding. A human monoclonal antibody derived from an infertile woman with sperm-immobilizing antibodies, whose serum showed an inhibitory effect on HZA, did not inhibit the HZA.


CONCLUSIONS
There are at least two kinds of sperm-immobilizing antibodies, one with both activities of sperm immobilization and blocking of sperm-zona tight binding and another with the former activity alone. The vast majority of sperm-immobilizing antibodies reduce zona binding even without the presence of complement.
Department of Obstetrics and Gynecology, Hyogo Medical College, Japan.
H
H
Shibahara
L J
LJ
Burkman
S
S
Isojima
N J
NJ
Alexander
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000276:immunology / Q000302:isolation & purification; D007247:Infertility, Female / Q000097:blood / Q000276:immunology; D008297:Male; D051379:Mice; D013081:Sperm Motility; D013084:Sperm-Ovum Interactions; D013094:Spermatozoa / Q000276:immunology*
D000906:Antibodies; D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments