Characterization and Regional Binding of Human Sperm Monoclonal Antibodies

Passive immunization with antisperm monoclonal antibody ZAP-7 increases preimplantation embryo mortality in the mouse

OBJECTIVE

To evaluate the effect of VIC-1 and ZAP-7 antihuman sperm monoclonal antibodies on in vivo fertility in the mouse.

DESIGN

A randomized blinded study using a mouse model.

SETTING

University-based laboratory.

ANIMALS

B6CBAF1 mice (n = 6 per experimental group).

INTERVENTION(S)

Antisperm antibodies were administered intravaginally to female mice before mating. Control mice received no treatment, saline, or nonspecific antibodies. Number and viability of preimplantation embryos were determined by microscopic observation. Mouse sperm, oocytes, and normal preimplantation embryos were used in indirect immunofluorescence assays with antisperm antibodies. The effect of antibody treatment on sperm motility and vitality was evaluated.

MAIN OUTCOME MEASURE(S)

Antigen expression, sperm motility and vitality, number and viability of embryos.

RESULT(S)

ZAP-7 antibody recognizes a sperm antigen expressed in zygotes and early preimplantation embryos. Passive immunization with ZAP-7 increases embryo mortality significantly (more than 40% above controls). Passive immunization with VIC-1 has no deleterious effect.

CONCLUSION(S)

ZAP-7 monoclonal antibody disrupts fertilization and embryogenesis in the mouse.

Flow cytometric determination of binding of monoclonal antibodies to human spermatozoa

Although several monoclonal antibodies to sperm antigens are available, only few systematical reports on the appearance of distinct antibody binding structures in spermatozoa of infertile patients are available. We studied the binding frequency of six monoclonal antibodies (TUS-1, -2, -10, -17, -19, -20) by means of a flow cytometer in different semen samples and their possible relationship to other sperm parameters, in particular to the motility parameters as determined by computer-assisted semen analysis. The percentage of vital spermatozoa binding the different antibodies was 21.5% (TUS-2) to 52.1% (TUS-20). The percentage binding was higher in samples with normozoospermia than in those with oligo-asthenoteratozoospermia. A significant correlation occurred between sperm concentration and the percentage of spermatozoa stained by TUS-2 and TUS-17; between motile spermatozoa and those binding TUS-17 and TUS-20; the velocity average path and those binding TUS-17; an inverse correlation occurred between the morphologically-abnormal spermatozoa and those binding TUS-20; an inverse correlation between TUS-17 and acrosin. We conclude from our results that although the antigens of the antibodies concerned are not yet characterized, the determination of antibody binding will give additional information on the functional status during capacitation and acrosome reaction of spermatozoa.

Human sperm coating antigen from seminal plasma origin

Sperm surface glycoproteins may be involved in sperm-zona pellucida recognition. Some of these coating proteins are of seminal plasma origin and their expression may change in the process of capacitation and acrosome reaction. Sperm specific monoclonal antibodies (mAb) define the presence and role of sperm membrane associated proteins. We have isolated a monoclonal antibody (SEM-12) specific for human sperm that shows, by indirect immunofluorescence, a discontinuous distribution of the antigen on the head and tail surfaces of non capacitated sperm. This antigen is also present in human seminal plasma as detected by ELISA. The antigen is detectable in sperm of goat, ram, and mouse. Two proteins in the range of 80-84 kDa have been isolated by affinity chromatography with SEM-12 mAb. The same result is obtained by immunoprecipitation. This antibody inhibits sperm motility and acrosome reaction (spontaneous and A23187 ionophore induced.