Ability of antibody-bound human sperm to penetrate zona-free hamster ova in vitro

Human sperm acrosomal status, acrosomal responsiveness, and acrosin are predictive of the outcomes of in vitro fertilization: A prospective cohort study

The sperm acrosome reaction (AR) is a physiological secretory course of membrane fusion and hydrolytic enzymes, as well as matrix protein release, enabling spermatozoa to penetrate the egg surroundings. An instable acrosomal status before a specific stimulus, insufficient acrosomal responsiveness, or inadequate enzymatic activity of acrosomal content can be detrimental to male fertility. This prospective cohort study was designed to determine whether three human sperm acrosome evaluation parameters-including spontaneous AR rate, AR after calcium ionophore A23187 challenge (ARIC) rate, and modified Kennedy acrosin activity-can predict fertilization outcomes in vitro and are correlated with male characteristics. A total of 485 eligible couples undergoing in vitro fertilization (IVF) therapy were included in two phases of this study. In a 'construction phase', three acrosome evaluation parameters were determined simultaneously in 132 cases, whereas in a 'validation phase', the spontaneous AR rate was determined in 353 cases. The results of the 'construction phase' revealed that the spontaneous AR rate was the only significant predictor of fertilization outcome (unadjusted odds ratio [OR] = 0.68, 95% confidence interval [CI]: 0.53-0.88, P =  0.003; adjusted OR = 0.64, 95% CI: 0.43-0.95, P =  0.03), and the cut-off value for total fertilization failure (TFF) prediction, determined by ROC curve analysis, was 9.91%; higher acrosin activity was shown to predict a higher fertilization rate only when patients were divided into groups (≥25 μIU/10⁶ spermatozoa, 14-25 μIU/10⁶ spermatozoa, <14 μIU/10⁶ spermatozoa). The spontaneous AR rate was negatively correlated with sperm motility, forward progression motility, and normal morphology; modified Kennedy acrosin activity was positively correlated with normal morphology; and the ARIC rate was not correlated with any of the male characteristics. A similar result was obtained for the spontaneous AR rate in the 'validation phase', and the cut-off value in predicting TFF was calibrated for 9.52%. Clinically, patients can voluntarily choose spontaneous AR rate alone or in combination with modified Kennedy acrosin activity to predict TFF, and early rescue intracytoplasmic sperm injection (ICSI), half ICSI, or full ICSI should be considered in advance for men with spontaneous AR rates ≥9.52% or spontaneous AR rates ≥9.52% and AE activities <25 μIU/10⁶ spermatozoa.

Application of computer-aided sperm analysis (CASA) for detecting sperm-immobilizing antibody

PROBLEM

Since the 1970s, anti-sperm antibodies have been studied as a pathogenic factor contributing to infertility. The complement-dependent sperm-immobilization test (SIT) and quantitative SIT have been used as effective tools for detecting anti-sperm antibodies in clinical settings. These tests have been carried out traditionally by manually counting the number of motile sperm through eye estimation.

METHOD OF STUDY

In this study, we developed a novel method using computer-aided sperm analysis. The results were compared with those obtained by the traditional method.

RESULTS

The results were identical and 25 of 78 samples tested were positive and 53 samples were negative for sperm-immobilizing (SI) antibodies based on both methods. For SI-positive samples, the values of SI₅₀ obtained using the two methods correlated closely with high co-efficiency.

CONCLUSION

Using the novel method, manually counting the number of motile spermatozoa becomes unnecessary. The novel method presented here will increase the objectivity and convenience of using the SIT as a clinical indicator.

The Change of Semen Superoxide Dismutase and Acrosin Activity in the Sterility of Male Patients with Positive Antisperm Antibody

In this study, we report the change of semen superoxide dismutase (SOD) and acrosin activities in the male sterility patients with positive antisperm antibody (AsAb). The activity of SOD was measured by xanthine oxidase assay and sperm acrosin activity was calculated by BAEE/ADH. Our data show that compared with the normal fertility group, the semen SOD activity in AsAb-positive patients was significantly lower. Similarly, the sperm acrosin activity in AsAb-positive patients was also significantly lower. Our results suggest that the sterility resulting from positive AsAb may be related with the changes of semen SOD and sperm acrosin activities.

Toward standardization of the cut-off value for the direct immunobead test using the postcoital test in immunologically infertile males

PURPOSE

There is a need to improve our understanding of the cut-off value of the direct immunobead test (D-IBT).

METHODS

The subjects were 26 D-IBT-positive and 140 D-IBT-negative males. The results of post coital tests (PCTs) for each subject were examined.

RESULTS

A significant difference was observed in abnormal PCTs between values <20 % and those ≥20 % (P = 0.02). However, there was no significant difference in abnormal PCTs between values <50 % and those ≥50 % (P = 0.084).

CONCLUSIONS

A cut-off value of 20 % was correlated with the possibility of conception on treatment with IUI. The D-IBT is a screening test, and the value of 20 % initially suggested by Bronson et al. seems to be more appropriate than that of 50 % in the criteria defined by the World Health Organization.

What the sperm says and the egg hears - a tale of two proteins and more

While considerable information exists regarding the early interactions of spermatozoon and egg that lead to successful fertilization, the molecular biology of events that result in the incorporation of the spermatozoon within the cortical ooplasm is largely undefined. There is circumstantial evidence suggesting that this process involves the interactions of specific oolemmal receptors and their ligands on sperm that bear similarities to mechanisms used in phagocytosis by macrophages. We have postulated that the egg may act as a 'non-professional phagocyte' during its association with the spermatozoon. This review surveys those events, provides an historical context, and creates a paradigm for further investigation.

Incidence of antisperm antibodies in males with systemic autoimmune diseases

PROBLEM

To investigate if systemic autoimmune diseases could be one of the risk factors for developing antisperm antibodies (ASA) in males.

METHOD OF STUDY

Antisperm antibodies in the sera of 70 males with systemic autoimmune diseases and 80 healthy controls were examined, by using the indirect-immunobead test (I-IBT). The sperm immobilization test (SIT) was also performed to detect sperm immobilizing antibodies to the patients who were positive in I-IBT.

RESULTS

Among 70 males with systemic autoimmune diseases, five were I-IBT positives, with incidence of 7.1%. However, no positives existed in 80 healthy males. Compared with the healthy controls, the incidence of ASA in males with systemic autoimmune diseases was significantly higher (P = 0.020). None of these five ASA-positive patients had sperm immobilizing antibodies.

CONCLUSION

The incidence of ASA in males with systemic autoimmune diseases was significantly higher than in the healthy controls. Systemic autoimmune diseases may be one of the risk factors for developing ASA in men.

Evaluation of a nonhomogeneous endometrial echo pattern in the midluteal phase as a potential factor associated with unexplained infertility

OBJECTIVE

To determine whether the failure to develop a homogeneous hyperechogenic pattern in the midluteal phase is associated with decreased fecundity in infertile women who are not receiving follicle-maturing drugs.

DESIGN

Observational study.

SETTING

Outpatient infertility clinic of a University Medical Center.

PATIENT(S)

Two hundred ninety-six infertile women (> or =6 months) with regular menses, normal fallopian tubes and uterine cavity, and absence of severe male factor on their initial investigation cycle for follicular dynamic studies.

INTERVENTION(S)

Midluteal phase sonographic endometrial evaluation.

MAIN OUTCOME MEASURE(S)

Viable pregnancy rates (live fetus at end of first trimester) according to endometrial echo pattern in the midluteal phase. Other variables considered were age of patient, endometrial thickness and serum E(2) levels at midcycle and midluteal phase, midcycle echo pattern, and P levels in the midluteal phase.

RESULT(S)

The viable pregnancy rate was significantly higher in those women who exhibited a homogeneous hyperechogenic pattern (8.5%) compared to those women whose endometrium was found to be nonhomogenous (2.2%). No other confounding variables were found that could explain this outcome.

CONCLUSION(S)

A nonhomogeneous hyperechogenic sonographic endometrial echo pattern predicts lower fertility potential in women who are not receiving follicle-maturing drugs.

Interactive effect of semen and cervical mucus quality on postcoital test outcome: analysis from an andrological point of view

This study analysed the relationship between semen quality and the postcoital test (PCT) outcome in 616 couples, especially focusing on the interactive effect of semen and cervical mucus quality. When PCTs performed in the presence of unfavourable mucus were excluded, a significant correlation was found between semen parameters and PCT outcome. In oligo/asthenozoospermia, 46.7% of PCT outcomes were negative, while the remaining were positive. Notably, in the presence of an optimal mucus score, 39% of PCT outcomes were good (> or = 7 forward motile spermatozoa/high power field). In normozoospermia, 16% of PCT were negative. A suboptimal cervical mucus quality significantly affected the PCT outcome in the presence of oligo/asthenozoospermia, but not in normozoospermia. In couples with repeated PCT, a better mucus score was associated with a significant improvement of the PCT outcome. When the outcome of two PCTs performed in the same couples with an unmodified mucus score was compared, a good consistency of the results was observed. In conclusion, the PCT can provide information in additional to that obtained from conventional semen analysis, as the interactive effect of semen/cervical mucus cannot be accurately inferred from the separate evaluation of the two members of a couple.

Male antisperm antibodies: association with a modified sperm stress test and lipid peroxidation

We previously reported a modified sperm stress test (MOST), low scores (< 0.39) in which were associated with sperm-related abnormal in vitro fertilization. Preliminary observations suggested that the presence of male sperm antibodies (ASA) could give low MOST scores. It was therefore decided to undertake a study to verify this possible association and also to ascertain if such a relationship was causal in nature. Six hundred and fifty semen samples from patients consulting for infertility were assessed for basic seminal characteristics, motion parameters (CASA), ASA and MOST. Thirty-nine samples (6%) were ASA-positive. Samples with and without ASA showed similar characteristics, except for percentage of normal forms and MOST scores (0.35 +/- 0.03 vs. 0.67 +/- 0.01, P < 0.001, for ASA-positive and -negative, respectively). There was a strong statistical association between presence of ASA and low MOST scores (P < 0.0001). One-hundred per cent of ASA-positive samples displayed low MOST scores. To verify the nature of this relationship, we incubated ASA-free spermatozoa with ASA-positive and -negative (control) sera. Despite an increase in the percentage of ASA-bearing spermatozoa in those aliquots incubated with ASA-positive serum, their original (pre-incubation) MOST scores remained unchanged. Furthermore, the rate of lipid peroxidation, indirectly reflected in MOST scores, was not different in the aliquots incubated with ASA. In conclusion, there seems to be a strong association between presence of ASA and low MOST values in semen samples of infertile patients; however, the relationship does not appear to be causal.

Sperm artificially exposed to antisperm antibodies show altered deoxyribonucleic acid

PURPOSE

Our purpose was to assess sperm deoxyribonucleic acid (DNA) integrity after exposure to antisperm antibodies.

METHODS

Donor semen were divided and exposed to sera containing IgG, IgA, and IgM antisperm antibodies. Untreated portions served as the control. After incubation (1 hr, 23 degrees C), the sperm were centrifuge-washed, resuspended, and incubated (23 degrees C) for 2, 5, 7, or 9 days. Acridine orange staining and kinematic parameters were measured. The sentinel (17q21 from D17S855) and beta-globin genes were amplified and analyzed using denaturing gradient gel electrophoresis.

RESULTS

Sperm preexposed to antisperm antibodies had deleted sentinel gene on days 7 and 9. The beta-globin gene was intact. There were no differences in acridine orange staining.

CONCLUSIONS

Sperm artificially exposed to antisperm antibodies resulted in a subtle deletion of genetic material. The DNA alteration process was slow and was undetectable at the gross level. More studies are needed to confirm the findings and determine whether DNA repair mechanisms can reverse the damage.

An investigation of the latency period between sperm oolemmal adhesion and oocyte penetration

In clinical studies of the ability of capacitated human sperm to penetrate zona-free hamster eggs, we have previously observed that the ratio of oolemmal adherent to penetrating sperm varied between men. Sperm incorporation did not occur immediately following gamete adhesion and not all adherent sperm penetrated the egg. To further investigate this phenomenon, comparisons were made of the kinetics of gamete adhesion, membrane fusion, and sperm incorporation of capacitated mouse and human spermatozoa by zona-free hamster eggs and of mouse sperm by zona-free mouse and hamster eggs. Eggs were inseminated with either capacitated human or mouse sperm or combinations of both, washed out of sperm suspension after initial gamete adherence, and further incubated in sperm-free medium. Gamete membrane fusion was judged by dye transfer of Hoechst 33342 and sperm entry of the cortical ooplasm by observation of expanded sperm heads within acridine orange stained eggs. Oolemmal adherent mouse and human sperm fused with and penetrated zona-free hamster eggs at different times whether eggs were inseminated in parallel or with combinations of sperm of both species. Oolemmal adherent mouse sperm penetrated zona-free hamster eggs prior to their penetration of zona-free mouse eggs. Ultrastructural studies of zona-free human eggs inseminated with human sperm confirmed prior observations with hamster eggs that only acrosome-reacted human sperm adhere to the oolemma. These results have lead us to postulate that sperm entry into the egg may occur through a "zipper" mechanism involving the ligation of local gamete receptors similar to the incorporation of target particles by phagocytes and suggest that not all oolemmal adherent human sperm are capable of being incorporated although they have undergone an acrosome reaction.

Antisperm antibodies: etiology, pathogenesis, diagnosis, and treatment

OBJECTIVE

To critically review the English-language literature and describe the current diagnosis, prevalence, etiology, and treatment of antisperm antibodies (ASA).

DESIGN

A comprehensive literature search of the English-language literature published between 1966 and December 1997 was performed on MEDLINE. Articles were also located via bibliographies of published works.

RESULT(S)

Data were excerpted from articles identified by MEDLINE search. The diagnosis, prevalence, etiology, and treatment of ASA are described.

CONCLUSION(S)

There is sufficient evidence that ASA impair fertility in couples with unexplained infertility. A number of different methodologies are available, which may be used in their detection. However, in many cases, test interpretation is subjective. Although there is not enough evidence to support systemic treatment for ASA, application of a variety of assisted reproductive technologies improves outcome.

A convenient mixed immunobeads screen for antisperm antibodies during routine semen analysis

OBJECTIVE

To determine if leftover unused IgG, IgA, and IgM immunobeads could be combined as a convenient screen for antisperm antibodies in unwashed sperm. For comparisons, the mixed antiglobulin reaction (SpermMar) and immunobead test were performed.

DESIGN

Prospective comparative study.

SETTING

Clinical and academic research environment.

SUBJECT(S)

Donor human sperm negative for antisperm antibodies.

INTERVENTION(S)

Sperm specimens (n = 9) were equally divided and sera with antisperm antibodies added to one portion (positive control).

MAIN OUTCOME MEASURE(S)

Assessment of antisperm antibodies in sperm.

RESULT(S)

The mixed immunobeads screen qualitative results were the same for both the SpermMar and immunobead tests. The mixed immunobeads screen (positive when > or =10% motile sperm was bound) had a sensitivity and specificity of 100%. The percentages of bound sperm for the mixed immunobeads screen correlated with the SpermMar but not the immunobead test. The mixed immunobeads screen intraassay and interassay coefficients of variation were 28.9% and 45.6%, respectively.

CONCLUSION(S)

Matching results between the mixed immunobeads screen and the SpermMar or immunobead test suggested that the screen could be used to detect antisperm antibodies in unwashed sperm. There was no advantage to washing the sperm, although the screen was flexible and applicable for both unwashed and washed sperm.

Antisperm antibody treatment mode: levels of antisperm antibodies after incubation with TEST-yolk buffer and filtration using the SpermPrep II method

OBJECTIVE

To assess whether incubation in TEST-yolk buffer (TYB) or human tubal fluid (HTF) could alter the sperm membrane characteristics and its relationship to antisperm antibodies (ASA) and/or antigen detachment from the sperm membrane and to evaluate the filtration of those specimens and possible recovery of ASA-free spermatozoa.

DESIGN

A prospective clinical study.

SETTING

Andrology Institute of Lexington, Lexington, Kentucky.

PATIENT(S)

Twenty patients undergoing infertility treatment.

MAIN OUTCOME MEASURE(S)

Recovery of spermatozoa with reduced levels or antisperm antibody-free sperm after treatment with TYB or HTF, followed by filtration using the SpermPrepII method (Sephadex based).

RESULT(S)

Assessment of ASA using the direct immunobead test showed no significant differences between specimens incubated for 2 hours in seminal plasma (fresh) or HTF with regard to levels of IgA and IgG. The percentage binding of anti-IgA and anti-IgG immunobeads was significantly reduced in specimens incubated for 2 hours in TYB compared with specimens incubated in seminal plasma or HTF. Furthermore, selection of spermatozoa using the SpermPrepII filtration method significantly reduced the percentage binding of anti-IgA and anti-IgG immunobeads compared with specimens incubated in HTF.

CONCLUSION(S)

The results suggest that TYB either altered the sperm membrane properties so that there was a decreased affinity at the antibody and/or antigen sites or that the egg yolk proteins were absorbing the antibodies and/or antigens complexes from the sperm membrane surface. Incubation of spermatozoa in TYB followed by filtration with the SpermPrepII method improved the recovery of ASA-free spermatozoa by selectively entrapping spermatozoa with ASA bound to its surface.

Seminal plasma immunoglobulin concentrations in autoimmune male subfertility

The presence of anti-sperm antibodies (ASAs) in seminal plasma is associated with infertility. They have been shown to reduce sperm motility, interfere with cervical mucus penetration and gamete interaction, and have been shown to reduce spontaneous fertilization and pregnancy rates. Although some causes can be determined, in the majority of cases the initial event causing the immune sensitisation and the reasons for the continuing antibody secretion remains unknown. Quantitative determination of total IgG, IgA and IgM within seminal plasma had not been previously reported in patients with and without specific ASAs. Semen samples from 512 men presenting with infertility were analyzed. One hundred and forty-six men (28.5%) had seminal fluid ASAs as determined by the MAR or TAT tests. The total seminal plasma IgG and IgA concentrations were significantly elevated in the ASA-positive groups compared with ASA-negative groups (IgG: 8.83 mg/100 ml vs. 7.15, P = 0.0008; and IgA: 2.88 mg/100 ml vs. 1.64, P = 0.0001). Only 19 samples showed seminal fluid IgM, and there was no difference between the ASA positive or ASA negative samples. The significance of these findings is discussed.

Male immunologic infertility: sperm performance on in vitro fertilization

OBJECTIVE

To analyze sperm performance in a group of patients with male immunologic infertility treated with IVF-ET.

DESIGN

Retrospective clinical study.

SETTING

Patients attending a private IVF clinic.

PATIENT(S)

The study group comprised seven men with significant levels of surface-bound antisperm antibodies treated in nine IVF cycles. The control group comprised nine couples with female tubal infertility and no indication of male factor infertility treated on the same cycle.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Fertilization rate, early embryonic development, implantation, and clinical pregnancy rate (PR).

RESULT(S)

Forty-six (44.2%) of 104 inseminated oocytes were fertilized in the study group compared with 65 (84.4%) of 77 in the control group, which was a significant difference. Surface-bound antisperm antibodies significantly inhibited early embryonic cleavage in the study group (13 [28.3%] of 46 embryos with at least 3 blastomeres) compared with the control group (41 [63.1%] of 65 embryos, with at least 3 blastomeres). The percentage of good-quality embryos (grades 1 and 2) was similar in the study and control groups (71.7% and 78.5%, respectively). The percentage of poor-quality embryos (grade 4 and two pronuclei) was higher in the study group compared with the control group (13.9% versus 9.2%, respectively); however, the difference was not significant. The implantation rate and clinical PR were lower in the study group (3% and 11%, respectively) compared with the control group (9.5% and 44%, respectively), but the difference was not statistically significant.

CONCLUSION(S)

The fertilization rate and early embryonic cleavage of human embryos was found to be reduced significantly in patients with high levels of surface-bound antisperm antibodies. Moreover, embryonic quality and the PR may be compromised by the presence of significant levels of surface-bound antisperm antibodies.

A comparison of clomiphene citrate and human menopausal gonadotropin for use in conjunction with intrauterine insemination

OBJECTIVE

To compare the outcome of superovulation using clomiphene citrate (CC) versus hMG in conjunction with IUI.

DESIGN

Sequentially assigned, observational study. Couples initially were assigned to receive either CC or hMG for three cycles.

SETTING

The Clinical Outpatient Department of the Dartmouth-Hitchcock Medical Center.

PATIENT(S)

Eighty-three infertile couples.

INTERVENTION(S)

IUI with hMG use.

MAIN OUTCOME MEASURE(S)

Conception rate, term pregnancy rate (PR), and pregnancy complications, such as spontaneous miscarriage and multiple gestation.

RESULT(S)

Of 83 couples who underwent at least one treatment cycle, 29 (35%) conceived during the study period. The relative rate of conception for hMG versus CC was 2.08 (95% confidence interval [CI], 0.93 to 4.68). The relative term PR was 2.10 (95% CI, 0.77 to 5.73) for hMG versus CC. There was no difference in the miscarriage rate for hMG versus CC.

CONCLUSION(S)

Both the conception rate and the term PR were higher using hMG, compared with CC, in combination with IUI, and showed a trend toward statistical significance.

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.

DESIGN

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.

SETTING

Academic research environment.

MAIN OUTCOME MEASURE(S)

Indirect immunofluorescence and Covasphere rosetting.

RESULT(S)

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.

CONCLUSION(S)

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.

Interference of antisperm antibodies with the induction of the acrosome reaction by zona pellucida (ZP) and its relationship with the inhibition of ZP binding

OBJECTIVE

To determine whether antisperm antibodies can interfere with the induction of the acrosome reaction (AR) by the zona pellucida (ZP) and whether this interference also can occur in the absence of an inhibitory effect on ZP binding.

DESIGN

Prospective in vitro study.

SETTING

A tertiary care center, the Andrologic Clinic, University of L'Aquila.

PATIENT(S)

Sera from 12 infertile patients with high titers of circulating antibodies directed against the sperm head were studied.

INTERVENTION

None

MAIN OUTCOME MEASURE(S)

The effect of antisperm antibodies on ZP binding was evaluated by matching antibody-exposed and nonexposed donor sperm suspensions labeled with fluorescein or rhodamine, respectively, and incubated with the same salt-stored human ZPs. The effect of antibodies on ZP-induced AR was determined by challenging antibody-exposed and nonexposed donor sperm suspensions with human ZPs disaggregated with acidic NaH2PO4. Acrosomal status was evaluated using fluorescein-labeled Pisum sativum agglutinin and supravital stain Hoechst 33258. In some selected cases, the effect of antisperm antibodies on the acrosomal status of sperm bound to intact ZP also was evaluated using transmission electron microscopy.

RESULT(S)

Five of 12 sera exhibited an inhibitory effect on ZP binding. An inhibition of AR induction by disaggregated ZPs (ranging from 64% to 98%) was produced by all 5 sera with an inhibitory effect on ZP binding and by 2 of 7 sera without an inhibitory effect on ZP binding. The different effects of antisperm antibodies on AR induction by disaggregated ZP were confirmed by comparing with ultrastructural evaluations on the acrosomal status of sperm bound to intact ZP.

CONCLUSION(S)

Antisperm antibodies can interfere with the induction of AR by ZP. This inhibition can occur even in the absence of an inhibitory effect on ZP binding. Neither effect may occur.

Occurrence of the interference of sperm-associated antibodies on sperm fertilizing ability as evaluated by the sperm-zona pellucida binding test and by the TEST-yolk buffer enhanced sperm penetration assay

PROBLEM

This study was performed to evaluate the occurrence as well as the level of the interference of sperm-associated antibodies on fertilization process.

METHOD

Motile sperm suspensions from 28 infertile patients with high degree of autoimmunization against the sperm head were tested with the zona pellucida (ZP) binding test and with the sperm penetration assay (SPA) enhanced with TEST-yolk buffer. Both tests were also performed using donor sperm exposed and non-exposed to the patients' circulating sperm antibodies.

RESULTS

A low ZP-binding was exhibited by sperm from 50% of patients with normal semen profile. All normozoospermic patients with low ZP-binding showed circulating sperm-antibodies with inhibitory effect on ZP-binding, while no patient with normal ZP-binding showed circulating sperm-antibodies with inhibitory effect. No normozoospermic patient exhibited a negative SPA result, and only in 16% of cases the penetration index was slightly less than 2 (the lowest value exhibited by fertile controls). Circulating antisperm-antibodies did not significantly affect the hamster egg penetration.

CONCLUSION

Even in the presence of high degree of autoimmunization against the sperm head, sperm fusion with oolemma is not impaired after sperm preincubation with TEST-yolk buffer, while an impairment of the ZP-binding is demonstrable in half cases, when non-immunologic factors are excluded. A substantial role in this interference is likely exerted by IgG antibodies transuded from the blood into the genital tract.

Study of antisperm antibodies bound to the sperm cell surface and their relationship to circulating ASA

PROBLEM

Direct and indirect tests for antisperm antibody (ASA) detection are commonly used in laboratories for the diagnosis of male immunological infertility. Even though the two kinds of tests study the same immunological phenomena, frequently no perfect correlation is found even on large series of patients and with precise statistical models. The aim of the present investigation was to try to establish whether biological models can explain the antibody test results and if a predictive threshold can be established for expected positivity/negativity.

METHOD

The data relate to 667 patients, who were screened using the Direct Immunobead test (d-IBT) for ASA bound to the sperm surface and with the gelatin and tray agglutination test (GAT and TAT) in sera for circulating ASA. Correlation were studied and cases of no correlation were further analyzed.

RESULTS

The number of patients with a clinically significant positivity to d-IBT (binding percentage > or = 20%) was 134 (20.1% of total patients). The analysis of the results of direct and indirect tests shows that the discordances are due to differences in the Ig class of immunization or to the site of epitopes involved. In fact, as far the Ig class is concerned, if d-IBT shows a prevalent or exclusive IgG or IgA positivity, this results in a poor correlation between binding percentage to d-IBT and GAT-TAT titers. If both the Ig classes are involved, the level of positivity of the two kinds of test are strictly related. As far as the site of Ag-Ab reaction on the sperm surface is concerned, the wide immunization involving all the surface sperm antigens (mixed), shown by d-IBT, is related to higher indirect test titers.

CONCLUSION

Local and systemic antisperm immunizations are strictly related and a predictive threshold of expectation can be established to explain even apparently discordant direct and indirect results.

Higher pregnancy rates following treatment of cervical factor with intrauterine insemination without superovulation versus intercourse: the importance of a well-timed postcoital test for infertility

A randomized study comparing the efficacy of timed intrauterine insemination (IUI) without hyperstimulation to sexual intercourse was performed in women with cervical factor infertility. Among the strict requirements for inclusion in the study were a normal semen analysis in the male partner, as well as the failure to demonstrate any sperm with progressive forward motion in a postcoital test performed 8-12 h after intercourse at the time of a mature follicle. All other infertility factors were negative. The data demonstrated a statistically significant fecundity rate at 1 month when IUI was compared to intercourse (21.2 vs. 3.9%). These data suggest that carefully timed IUI in nonhyperstimulated cycles is an effective treatment for cervical factor infertility.

Interlaboratory interprotocol comparison of indirect immunobead assay for sperm-associated antibodies in serum

This investigation was designed to study the effect of two different protocols on the indirect sperm-associated antibody test on serum performed using Bio-Rad immunobead (IBT) at two andrology laboratories. Aliquots of 31 serum samples from infertile couples were analyzed by both protocols. The IBT was negative by both protocols (100% concordance) for 18 serum samples. Seven of the 13 remaining samples were positive by both protocols (> or = 10% bead attachment by protocol A and > or = 20% bead attachment by protocol B), for a concordance of 54%. The remaining six samples were positive by one of the two protocols. The overall concordance for positive and negative results was 81% (25 of 31 samples). Protocol A detected a higher percentage of bead attachments for IgG and IgA, while protocol B detected a higher percentage of bead attachments for IgM. The discordance in the results of IgA attachment obtained by the two protocols was statistically significant (p < .05). A standardized, uniform protocol for the indirect IBT is needed.

Variation in antisperm antibody results using different assays

PROBLEM

The detection of various types of antisperm antibodies (ASA) in the serum varies among different assays. This variation may influence the diagnosis and management of infertile couples who are tested for such immunologic factors. This prospective study was conducted to determine the variation in the results of ASA as measured by the sperm immobilization (SI), sperm agglutination (SA), and the indirect immunobead (IB) assays.

METHOD

The sera of 79 patients that tested positive for ASA by at least one of the assays listed above were concurrently tested with all three assays.

RESULTS

Using an individual ASA assay, 66 (84%), 26 (33%) or 36 (46%) of sera tested positive by the SA, SI, or IB assays, respectively. However, using a combination of assays, 67 (85%), 78 (99%) or 40 (51%) of sera tested positive using either the SA+SI, SA+IB or SI+IB assays, respectively.

CONCLUSION

These findings suggest that the utilization of different assays to detect ASA may detect sera that are positive for ASA with more reliability than single assay testing.

Production of mouse monoclonal antibodies directed against the oolemma of human and hamster oocytes by intra-splenic injection of oocytes

PROBLEM

To develop an additional approach for the study of oolemmal surface moieties involved in gamete interactions, we decided to obtain monoclonal antibodies by intrasplenic injection of human and hamster oocytes in Balb/c mice.

METHOD

Two Balb/c males were injected three times intrasplenically at 15-day intervalS with approximately 40 zona-free hamster and 3-5 zona-free human oocytes. After the third injection, spleen cells were fused and hybridomas developed. We used a novel screening system based upon the use of sections of frozen human and hamster eggs, tested by means of indirect immunofluorescence. The antibodies that we produced were evaluated for their ability to interfere with the zona-free hamster eggs penetration by human spermatozoa. The B2B5 antibody was also developed as ascitic fluid and further characterized.

RESULTS

Seven antibodies reactive with hamster oocytes were produced. Six of them also reacted with human oolemmas. The binding was confined to the oolemma, and no staining of the zona nor the cytoplasm was present. One of these antibodies reduced the penetration of zona-free hamster eggs by human spermatozoa. This antibody, B2B5, an IgM kappa, was confirmed to interact with the oolemma by means of indirect immunofluorescence of fresh eggs and Covasphere binding. B2B5 did not react with other human or hamster tissues except capacitated human spermatozoa. The reactivity with the oolemma of hamster oocytes was not lost after egg penetration by human sperm.

CONCLUSIONS

Intrasplenic immunization using zona-free human and hamster oocytes allows the production of anti-oolemma antibodies. A system of screening based upon the use of sections of frozen eggs also allows an easy and quick scoring of many supernatants. B2B5 monoclonal anti-oolemma antibody deserves further studies in that is able to interfere with fertilization and its antigen appears to be confined to the gametes surface.

Vitronectin is an intrinsic protein of human spermatozoa released during the acrosome reaction

Evidence has been presented that oolemmal integrins and their ligands on spermatozoa may play a role in gamete interactions leading to fertilization. We previously demonstrated that vitronectin (Vn) could be extracted from fresh human spermatozoa and detected in Western blots, and Vn was observed on the surface of living, capacitated sperm by indirect immunofluorescence. In the present experiments, messenger RNA encoding Vn was detected in human testis poly (A+) RNA using Northern analysis, and Vn was localized within the acrosomal region of ejaculated sperm by immunoperoxidase and immunofluorescence staining. During the acrosome reaction, induced in capacitated spermatozoa by lonomycin, Vn was released into the medium in a calcium-dependent manner. Vn appears to be a specific product of intratesticular spermatozoa that is secreted during the acrosome reaction. These findings suggest that Vn is positioned to play a strategic role in gamete interactions leading to fertilization.

Antibodies to human seminal plasma inhibin adversely affect sperm function parameters

Polyclonal antibodies to intact inhibin (94 amino acids, R-94, 10.5 kDa) and its sequence specific synthetic fragments (R-9, R-17) were evaluated for their effect on various physical and biochemical parameters of sperm function. Intact inhibit had maximum deleterious effect on quantitative motility and mean forward progression of spermatozoa. Antibodies had no effect on sperm fructolysis and sperm nuclear chromatin decondensation reaction. Sperm plasma membrane was damaged in antibodies treated spermatozoa as evidenced by hypoosmotic swelling test and sperm lipid peroxidation reaction.

Failure of test yolk buffer to decrease antisperm antibodies on sperm

The objective of this study was to evaluate whether the suspension of sperm naturally bound or artificially coated with antisperm antibody (ASA) in test yolk buffer (TYB) will reduce the percentage of sperm positive for ASA. Attempts were made to repeat a study performed by Lam et al., in which they claimed a significant decrease in percentage of sperm positive for both IgA and IgG. Furthermore, the study attempted to determine if this methodology would similarly reduce the percentage of sperm naturally bound with ASA. There was no reduction in postincubation levels in percentage of sperm having attachment of IgA or IgG in either the sperm specimens naturally bound with ASA or donor sperm artificially coated with antibodies. Incubation in TYB does not appear to be an effective method to reduce the percentage of sperm bound with ASA. Possibly, it could reduce the amount of ASA bound to each sperm, but this would have to be proven by other studies.

Sperm-immunobead binding decreases with in vitro incubation

OBJECTIVE

To characterize the stability of the sperm-immunobead association over time.

DESIGN

Prospective evaluation of sperm-immunobead binding, using direct and indirect assays.

SETTING

Male Infertility Clinic, University of California, Davis, Davis, California.

PATIENTS

Eleven men with sperm surface antibodies and 25 men with serum antisperm antibodies volunteered.

MAIN OUTCOME MEASURES

Repeated assessment of sperm-immunobead binding over time.

RESULTS

Serum immunoglobulin (Ig)G decreased a mean of 42.6% over 30 minutes, and serum IgA decreased a mean of 22.7% over 30 minutes. Semen-derived IgG binding fell a mean of 59.9% and semen-derived IgA fell a mean of 27.0% over 25 to 40 minutes.

CONCLUSIONS

Sperm-immunobead coincubation results in a decrease in the number of sperm bound to immunobeads.

Impaired hamster egg penetration by human sperm from ejaculates with low acrosin activity but otherwise normal

OBJECTIVE

To determine if a low acrosin activity in otherwise normal ejaculate from infertile patients is associated with an impairment of sperm functions involved in the hamster egg penetration.

SETTING

A tertiary care center, the Andrology Clinic, Department of Internal Medicine, University of L'Aquila.

PATIENTS

Nine infertile patients with low acrosin activity in otherwise normal ejaculate (including normal immunoreactivity for acrosin) were studied; nine fertile men served as a control group. The two groups were homogeneous for seminal parameters.

INTERVENTIONS

The hamster egg penetration assay and the acrosome reaction rate assessment were performed on capacitated sperm suspensions in basal conditions and after ionophore challenge.

MAIN OUTCOME MEASURES

The penetration rate, the penetration index, and the acrosome reaction rate were measured and compared between the groups.

RESULTS

No penetration was achieved in seven patients and a low penetration was achieved in two cases. The difference with the control group was significant. The ionophore challenge was associated to penetration of hamster eggs in seven of nine patients, but the penetration index was significantly lower than the controls. Acrosin activity was correlated to hamster egg penetration. Both spontaneous and induced acrosome reaction rate were similar in the two groups.

CONCLUSIONS

A low sperm acrosin activity in otherwise normal ejaculate is associated with an impaired hamster egg penetration. This impairment does not seem to be due to altered dynamics of acrosome reaction.

Sperm antibody status does not correlate with egg penetration ability

During a 6-month period 59 semen specimens were subjected to the direct immunobead test and 12 were positive (15% or more of sperm bound by IgA or IgG to the head, mid piece or principal piece of the tail, for an incidence of 20%). Mean motility and forward progression (scale of 0 to 4) were 47% (range 10 to 80) and 1.7 (range 1 to 3), respectively, in the positive test group, whereas these values were 53% (range 1 to 90) and 2.2 (range 1 to 3), respectively, in the negative test group. Sperm penetration assay was performed on 11 of the 12 direct immunobead test positive specimens. A normal sperm penetration assay score was noted in 5 of the 11 specimens (46%), a subfertile score in 4 (36%) and an infertile score (no penetrations) in 2 (18%). The incidence of scores in these 3 subcategories of fertility status in the direct immunobead test positive group did not differ significantly from distribution of scores from all 87 sperm penetration assays performed at our laboratory during the same period: normal--39 of 87 (45%), subfertile--35 (40%) and infertile--13 (15%). Furthermore, there was no pathognomonic binding pattern for those antibody positive patients with subfertile or infertile scores. In conclusion, sperm antibody positivity is typically independent of egg penetration ability, there is no pathognomonic antibody binding pattern for poor egg penetration and there is a tendency for antibody positive sperm to have a lower percentage of motility and forward progression.

The incidence of antisperm antibodies in infertility patients with a history of cryptorchidism

Infertility in patients with a history of cryptorchidism is usually the result of oligo-asthenospermia. In this study we analyzed the incidence of antisperm antibodies in infertility patients with a history of cryptorchidism, general infertility patients and donors of known fertility. Of the cryptorchid patients 66% tested positive for antisperm antibodies compared to 2.6% of the control group of infertile patients and 2.8% of the donors of known fertility. Sperm progressive motility was significantly (p < 0.05) decreased in the cryptorchid patients testing positive for antisperm antibodies compared to those testing negative for antisperm antibodies, and compared to both control groups. Of the patients treated for cryptorchidism by orchiopexy 52% were positive for antisperm antibodies, and the mean patient age at orchiopexy was significantly (p < 0.01) higher in the positive antibody group (14.2 +/- 1.2 years old) than the negative antibody group (8.6 +/- 0.8 years old). While decreased sperm concentration, motility and morphology are usually the primary causes of infertility in patients with a history of cryptorchidism, it appears that the presence of antisperm antibodies is also increased in these patients, which may contribute to reduced fertility.

Effect of human sperm capacitation treatments on the penetration of freshly obtained and zona-free frozen hamster oocytes

A study was conducted to evaluate the effect of sperm capacitation treatments on hamster egg penetration test (HEPT) values when using freshly obtained and zona-free frozen hamster oocytes. Semen was collected from 12 healthy donors with proven fertility and each sample processed by a sperm swim-up method, incubation in human follicular fluid (hFF), Percoll centrifugation, and refrigeration in test-yolk buffer (TYB). Capacitated sperm were then incubated with fresh and frozen-thawed eggs and the percent penetration scores and indices were calculated. Motility values of pre- and postprocessed sperm were also determined. A significant overall reduction in percent penetration scores but not penetration indices was observed when using frozen oocytes. However, within sperm treatments, differences between fresh and frozen oocytes were observed for the sperm swim-up, hFF incubation, and Percoll centrifugation groups, but not for TYB. Differences in sperm movement parameters according to sperm treatment did not appear to reflect specific penetration scores. In conclusion, despite the practical advantage of using frozen oocytes over freshly obtained oocytes for the HEPT, the specific sperm capacitation treatment must be considered a factor when the decision to use fresh or frozen oocytes is made. Furthermore, these findings reinforce the need to carefully reevaluate the predictive value of the HEPT any time modifications to the test are introduced.

Relationship of sperm antibodies in women and men to human in vitro fertilization, cleavage, and pregnancy rate

PROBLEM

The presence of anti-sperm antibodies (ASA) in female serum has been correlated with decreased fertilization in the in vitro fertilization (IVF) program; however, the impact of each type of ASA (IgG, IgA, IgM) is not known.

METHOD

To clarify the role of each ASA subtype, the immunobead binding technique was used to identify IgG, IgA, and IgM ASA in the female sera and on the spermatozoa from 137 couples undergoing the IVF program.

RESULTS

Couples with ASA on spermatozoa had a lower fertilization rate and lower number of transferred embryos: and IgG was the major immunoglobin involved. Couples with ASA in female sera showed significant decreases in the rates of fertilization, cleavage, and number of transferred embryos only when IgM was detected, but not IgG or IgA. However, the presence of IgA ASA in female sera was only associated with a decrease in pregnancy rate, although the number of transferred embryos was not reduced.

CONCLUSION

These findings suggest that ASA can influence the results of IVF and that the specific effect is dependent upon the subtypes of ASA.

Antisperm antibody binding to human sperm inhibits capacitation induced changes in the levels of plasma membrane sterols

PROBLEM

Human spermatozoa express mannose ligand receptors (MLRs) over the entire head when incubated under conditions that promote loss of free cholesterol. Binding of IgA, IgG, and/or IgM head-directed anti-sperm antibodies (ASAs) to freshly isolated sperm blocks MLR expression in a dose dependent manner.

METHODS

Comparison of Western blots of immunoprecipitated glycoproteins from fresh sperm exposed to ASAs from women with those of sperm membrane proteins isolated from capacitated sperm probed with a goat anti-human macrophage MLR antiserum showed that ASAs do not react with human sperm MLRs of 48 and 61 kd apparent molecular weight.

RESULTS

The direct effect of ASA binding was to increase membrane free cholesterol content which remained greater than 0.005 mumol/10(9) sperm after 18 h incubations, whereas the sterol content of controls decreased to less than 0.001 mumol/10(9) sperm. Cholesterol addition to sperm inhibited MLR expression in a manner analogous to ASA binding, while increasing temperatures up to the crystalline/liquid-crystalline phase transition for sperm membranes; less than 45 degrees C failed to promote the appearance of MLRs on the surface of fresh sperm.

CONCLUSIONS

We conclude that ASA effects on membrane cholesterol content prevent the membrane fluidity changes needed for MLR expression.

Effect of sperm-associated antibodies on human sperm ability to bind to zona pellucida and to penetrate zona-free hamster oocytes

Antibodies directed against sperm membrane antigens located mainly over the sperm heads were eluted from the sperm cell fraction of autoimmune ejaculates and transferred to antibody-negative spermatozoa of fertile donors. The ability of these antibody-coated spermatozoa to bind to the human zona pellucida and to penetrate zona-free hamster oocytes was evaluated in vitro. The majority of the sperm-eluted samples contained both IgA and IgG antibodies. In order to evaluate the effect of each class of antibody on the analyzed sperm functions, each isotype was specifically absorbed before transfer. Sperm-binding to salt-stored zona pellucida, as assayed by FITC and TRITC labeling of antibody-free and antibody-coated spermatozoa incubated with the same zona, was consistently reduced by 60-85% by the five eluted samples tested. Removal of either IgA or IgG antibodies from the eluted samples did not change the overall effect. Sperm penetration of zona-free hamster eggs was variously affected by sperm-associated antibodies. Of the 8 samples of sperm-eluted antibodies tested, only 4 had a significant effect on sperm penetration. Three of them decreased the penetration by 67-78%, while the fourth exhibited a modest increasing effect of 39%. These four samples contained antibodies of the two isotypes. In the samples with a decreasing effect, the elimination of one or another of the two isotypes restored the ability of the sperm to penetrate the hamster oocytes. These results suggest that sperm-associated antibodies may have different effects on zona-binding and gametic fusion events that lead to fertilization. Whereas IgA and IgG antibodies taken together or separately decreased sperm binding to the human zona pellucida, the two classes of antibodies must be associated in order to impair sperm penetration into zona-free hamster oocytes.

The detection of antisperm antibodies in serum: a comparison of the tray agglutination test, indirect immunobead test and indirect SpermCheck assay

Testing for antisperm antibodies (ASAs) is an important part of the work-up of the sub-fertile couple, yet there is little consensus regarding the most appropriate methods. The SpermCheck assay (GSC; Bio-Rad Laboratories Inc., Diagnostics Division, Hercules, CA, U.S.A.) is supplied with wash buffer, controls and bead reagent which detects all three major classes of ASAs (IgA, IgG and IgM) in a single test. This study compared results on a bank of samples using the tray agglutination test (TAT), immunobead test (IBT), GSC and a modified SpermCheck assay to detect a single isotype in each test (SISC). The IBT and SISC showed excellent correlation, with 127/141 (90.1%) tests agreeing. There was an apparent lack of sensitivity to IgM with GSC as 8/15 (53.3%) samples testing positive with IBT and 7/15 (46.7%) testing positive with SISC were negative with GSC. Of the 24 IBT-negatives, seven (29.2%) were positive for TAT, indicating a high incidence of non-immunological agglutination, though this decreased as the TAT titre increased. The proportion of samples testing positive for IBT increased with TAT titre: 3/20 (15.0%) for TAT-negative samples, 6/10 (60.0%) for low titres and 21/24 (87.5%) for high titres. This was also observed when comparing the GSC with TAT. The TAT therefore appears useful as a first-line screen, whilst the inability of the GSC to adequately detect IgM limits its use as an indirect test. Both the IBT and SISC can be used to further investigate the type and class of ASA present.

Effect of ionophore challenge on hamster egg penetration and acrosome reaction of antibody-coated human sperm

PROBLEM

Following the demonstration that antisperm antibodies do not affect the spontaneous acrosome reactions (AR) of human sperm used for the hamster egg penetration assay (HEPA), we evaluated the effect of the ionophore challenge on HEPA and AR of antibody-coated sperm.

METHOD

Motile sperm suspensions from donors were exposed to serum and seminal plasma samples with sperm-head-directed antibodies, washed, capacitated, and challenged with ionomycin.

RESULTS

The proportion of acrosome-reacted sperm, assessed by fluoresceinated Pisum sativum agglutinin and supravital stain Hoechst 33258, was significantly higher in the antibody-exposed sperm than in the controls (47.0 +/- 13.2% vs. 39.3 +/- 12.1, respectively; P < 0.05). However, the hamster egg penetration rate and index were not significantly different between antibody-exposed sperm and controls (98.0 +/- 3.7% vs. 85.9 +/- 16.2% and 6.64 +/- 4.1 vs. 6.81 +/- 4.8, respectively). Only one of eight test samples with antisperm antibodies, where the highest increase of AR rate compared with controls was observed (55.0% vs. 35.6%) produced a substantial increase of penetrations per oocyte (7.4 vs. 4.1).

CONCLUSION

The ionophore challenge enabled us to recognize a subtle effect of anti-sperm antibodies on the dynamics of acrosomal loss, the clinical relevance of which needs to be elucidated.

Antisperm antibodies in women: variability in antibody levels in serum, mucus, and peritoneal fluid

OBJECTIVE

To look for patterns of antisperm antibody expression in women by exploring the levels of antisperm antibodies in different body fluids. This was achieved by studying sequential serum samples from individual patients and by comparing the levels of antisperm antibodies in serum from a number of patients with the levels of antisperm antibodies in cervical mucus or peritoneal fluid (PF).

DESIGN

Prospective studies were performed on sequential serum samples within a menstrual cycle. Retrospective studies were done to compare antisperm antibodies in serum and mucus or PF. The immunobead assay was used to measure antisperm antibodies in these fluids.

SETTING

Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire.

PATIENTS

A random sample of patients undergoing evaluation for infertility.

RESULTS

The levels of antisperm antibodies in sera drawn from patients at different points in a menstrual cycle stimulated by the presence of exogenous hormones did not change during the follicular phase of the menstrual cycle. Also, in many samples, the antisperm antibody level in serum did not correlate with the antisperm antibody levels in mucus or PF.

CONCLUSIONS

The data suggest that measurement of antisperm antibodies at a single point in time or from a single fluid is not sufficient when evaluating a woman for immunological infertility. The data also suggest that numerous and complex factors contribute to the expression of antisperm antibodies in women.