Detection of antispermatozoal antibodies of IgG, IgA, and IgM immunoglobulin classes in cervical mucus

Antisperm antibodies and conception

Sperm have been known to be antigenic for more than a century. There is a strong body of evidence that in humans and in other species at least some antibodies that bind to sperm antigens can cause infertility. Therefore, these antibodies are of interest today for two practical reasons. Firstly, the association of the antibodies with infertility means that they must be detected and then the couples treated appropriately. Secondly, because these antibodies can induce infertility they have the potential to be developed for contraceptive purposes in humans and also for the control of feral animal populations.

Are antisperm antibodies indeed sperm-specific?

Antisperm antibodies (ASA) are present in a high percentage of infertile patients. The development of ASA in the male depends on the sequestration of antigens on germ cells, the testis being an immune privileged region. In this study, we investigated the specificity of ASA binding to sperm antigens by exposing a number of organ preparations to ASA. In none of the organ homogenates was a significant difference between the results of the Western blot with ASA-containing fluids, neither serum nor seminal plasma, and those without ASA observed. We conclude from our results that the ASA tested in our study obviously are sperm-specific. ASA as an autoimmune are thus restricted to spermatozoa. The antigens are suitable for trials in immune therapy, they may also serve for the development of antigen-specific diagnosis and treatment in infertility. They also indicate cognate antigens of possible immune contraceptive agents.

The characterization of human spermatozoa membrane proteins--surface antigens and immunological infertility

The aim of this study was to isolate and characterize highly enriched membrane proteins by two-dimensional (2-D) electrophoresis and to identify surface antigens binding sperm autoantibodies (SpAb). The presence of SpAb may reduce fertility by affecting sperm motility and acrosome reaction. The presence of the SpAb was shown to prevent sperm penetration of cervical mucus, to inhibit sperm-zona pellucida interaction, and to interfere with the sperm-egg fusion. The swim-up method was used to separate mature and motile sperm. Sperm membranes were obtained by hypoosmotic swelling, homogenization and sonication. Membranes were further isolated by differential centrifugation steps. The highly purified human sperm membrane proteins were separated by two-dimensional gel electrophoresis and electrotransferred to polyvinylidene difluoride (PVDF) membrane. The antigens were identified by bound SpAb, the sources of which were seminal plasma samples of infertile patients or of patients following vasectomy. Fourteen surface antigens were detected. Their identification may be (i) important for understanding the mechanism by which SpAb impair sperm fertilization capacity, (ii) suitable as a basis of new methods of fertility regulation, and (iii) helpful in developing reproducible and reliable methods for determinations of SpAb.

Anti-sperm antibodies in female mice: responses following intrauterine immunization

PROBLEM

The goal of this study was to measure anti-sperm antibodies in serum following intraluminal uterine immunization and to compare this with the formation of antibodies following intraperitoneal (i.p.) or anal immunization.

METHOD

Mice were immunized with human sperm, and antibody was measured using an indirect immunobead assay.

RESULTS

High levels of anti-sperm antibodies could be measured following intrauterine immunization and i.p. immunization. Anal immunization resulted in lower levels of antibody formation. Antibody formation after intrauterine immunization was less consistent following transcervical insertion than following needle insertion of sperm.

CONCLUSION

The data suggest that intrauterine immunization can result in anti-sperm antibody formation under some conditions.

The role of antisperm antibodies in infertility

OBJECTIVE

To discuss the role of antisperm antibodies (Ab) in infertility, including proposed mechanisms of antisperm Ab formation, assays for their detection, and treatments for immune-mediated infertility.

DESIGN

Major studies in the published literature and data from The University of Texas Southwestern Medical Center, Division of Reproductive Endocrinology. Reports were reviewed that investigated the development and impact of alloimmunity and autoimmunity to spermatozoa in men and alloimmunity in women and the current methods of treatment for resultant subfertility.

RESULTS

The exposure of spermatozoal antigens to the mucosal and systemic immune systems results in development of immunity to a multiplicity of spermatozoal epitopes. The evaluation of studies that examine the role of antisperm Ab in infertility is complicated by the lack of standardization of antisperm Ab assays and the difficulty in identifying those epitopes for antisperm Ab binding that are responsible for subfertility. Sperm-associated antisperm Ab and antisperm Ab in cervical mucus (CM) reduce sperm mobility and may also impair sperm-ovum interaction. The clinical significance of serum antisperm Ab in both men and women, however, is controversial. Current therapy for antisperm Ab associated infertility is empiric and largely unproven.

CONCLUSIONS

Antisperm Ab on the sperm surface and in CM are implicated in the pathogenesis of a subset of patients with infertility. Further studies that determine the clinically relevant sites of antisperm Ab interaction will aid in directing the treatment of subfertility mediated by antisperm Ab.

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.

Secretory monoclonal IgA antibody to human sperm produced by gastrointestinal immunization inhibits human sperm activity and mouse in vitro fertilization

BALB/c mice were immunized intragastrically with human sperm. Cells from the Peyer's patches and spleens of the immunized mice were for the preparation of hybridomas secreting antisperm monoclonal IgA (mcIgA). The specific ratio of IgA-secreting cells in Peyer's patches was much higher than that in spleen. The binding site on human sperm of 9 of 19 mcIgA was in the post-acrosomal region using an immunofluorescent assay. Two of eight selected mcIgA caused strong human sperm agglutination and three of them produced significant inhibition of mouse in vitro fertilization. No mcIgA tested caused obvious human sperm immobilization or inhibited mouse in vivo fertilization. In vitro assembly of selected mcIgA in ascites with mouse secretory component (SC) caused no significant changes in effects on sperm function and in vitro fertilization. By use of Western blotting, dimer or higher polymers were demonstrated in all selected mcIgAs and corresponding protein antigens in 6 of 8 selected mcIgAs. These results suggest that human sperm function may be inhibited and fertilization rate reduced by specific secretory IgA to human sperm and that secretory immunity to protein antigens of human sperm could be induced by intragastrointestinal immunization.

A study of the detection of sperm antibody in cervical mucus with a modified immunobead method

OBJECTIVE

To develop a new immunobead binding test (IBT) procedure that will detect sperm antibody in cervical mucus (CM), especially in very small samples of mucus.

DESIGN

After the interaction of donor sperm with bromelin-dissolved CM, the motile sperm cells were separated from other cells and debris and then tested with a standard immunobead method.

SETTING

The CM and serum samples were obtained from a sequence of referred patients who were sent to this testing laboratory.

PATIENTS

There were 60 women who provided 64 samples of CM and 41 samples of blood serum. They were partners in infertile couples.

INTERVENTIONS

None.

MAIN OUTCOME MEASURE

A useful distinction was made between positive and negative results for the mucus samples by this CM-IBT procedure. The usable samples of mucus could be as little as 0.05 g (wet weight).

RESULTS

From the 60 women, seven mucus samples were positive; in the repeated testing, the same results were obtained with five of the six positive samples and seven of seven negative samples.

CONCLUSION

This method (CM-IBT) can be clinically useful for detecting sperm antibody in CM, especially because it is effective for tiny samples. In this method, the motile sperm cells are better separated from the debris after the incubation step. When the IBT was applied to the serum samples from the same women, there was no correlation between serum-IBT and CM-IBT, showing that both materials must be tested.

Antisperm antibodies in women undergoing intrauterine insemination

Intrauterine insemination is widely used for the treatment of infertility as a result of cervical or male factors or empirically before in vitro fertilization or gamete intrafallopian transfer. This study was designed to confirm or refute the theoretical concern that intrauterine insemination may induce antisperm antibodies in such women. Serum and cervical mucus were obtained at the first, fourth, and sixth intrauterine inseminations. The serum was screened by the Immunobead test for IgG and IgA. If screening results were positive (greater than 10% binding), antisperm antibodies were titered by the microimmobilization and microagglutination tests. The Immunobead test was performed on the cervical mucus after liquefication with bromelin. Ninety-three patients were followed up prospectively. Of these, 40 completed six intrauterine insemination cycles and the remaining 53 completed four cycles. Low transient antisperm antibody levels were detected in 10.8% of the patients and would not be expected to affect the prognosis for fertility. It is concluded that intrauterine insemination does not induce significant antisperm antibody production in women.

A radiolabeled antiglobulin assay to identify human cervical mucus immunoglobulin (Ig) A and IgG antisperm antibodies

Antisperm immunoglobulin (Ig) A and IgG antibodies in human cervical mucus (CM) were identified by a radiolabeled antiglobulin assay. Cervical mucus samples from fertile and infertile women were exposed to a 1:3,200 dilution of 2-mercaptoethanol (2-ME), and 5 micrograms of the solubilized CM protein were assayed for the presence of IgA and IgG antisperm and anti-Candida activity by the radiolabeled antiglobulin assay. Purified human secretory IgA and IgG exposed to 2-ME retained the molecular integrity and functional activity of the untreated antibody molecules. CM aliquots collected after high-performance liquid chromatography (HPLC) fractionation were assessed for antisperm antibody activity; antisperm antibody activity was retained in the appropriate IgA or IgG CM fractions. The incidence of CM antisperm antibodies was minimally affected when the radiolabeled antiglobulin assay was performed with a motile sperm population. Approximately 70% of the CM IgA antisperm antibodies were of the IgA1 subclass; CM IgG was primarily of the IgG4 subclass. When Candida antigen was substituted for sperm in the radiolabeled antiglobulin assay, the CM antisperm antibodies were found to be exclusively sperm-specific. These data indicate that the radiolabeled antiglobulin assay using 2-ME to extract CM antibodies is a specific method for the assay of antisperm antibodies in CM.

Effect of antispermatozoal antibodies in seminal plasma upon spermatozoal function

The indirect immunobead test for antispermatozoal antibodies of the class IgA, IgG and IgM was applied to the seminal plasma of male partners of infertile couples. The presence of both IgA and IgG was associated with a decreased incidence of good post-coital test results and a reduced rate of fertilization of human oocytes. No significant differences were found for men with IgA or IgG alone when compared to men with no detectable antispermatozoal antibodies.

N-acetylneuraminic acid and hostile mucus infertility

A total of 39 samples of hostile mucus, as defined by postcoital examination, were examined for N-acetylneuraminic acid (NANA) deficiency, as measured by the enzymatic addition of NANA, spermatozoal penetration and immobilization. Only 56.7% of the mucus samples were deficient in NANA and this did not correlate with spermatozoal penetration or immobilization, which were negatively correlated. Thus, as the spermatozoal hostility in the mucus decreases, spermatozoal penetration increases. This finding also applies to hostile mucus not deficient in NANA. In contrast, resialylation of NANA hostile mucus, deficient and not deficient in NANA, although not enhancing spermatozoal penetration, did reduce spermatozoal immobilization. Thus, components of the mucus deficient in NANA and/or the lack of unbound NANA may contribute to mucus hostility, but it is not the only hostile factor. In addition, SEM studies of NANA-deficient mucin before and after resialylation were shown to have similar structures. Hence ultrastructural changes are not apparent in NANA-deficient mucin, and this supports the previous finding that NANA deficiency does not impede spermatozoal penetration. The spermatozoa from the husbands of the infertile couples formed three distinct groups in terms of spermatozoal penetration and immobilization in normal donor mucus. One group demonstrated normal levels of spermatozoal penetration and immobilization in donor mucus. A second group was demonstrable in which spermatozoal penetration was similar to that in the wife's hostile mucus, but had a normal level of spermatozoal immobilization. In the third group, both spermatozoal penetration and immobilization in donor mucus were similar to that in the wife's hostile mucus. The results demonstrate that not all hostile mucus is deficient in NANA, and that other unknown factors are involved. In addition, there are also male factors which may impede spermatozoal penetration and/or result in the inability of the spermatozoa to survive in normal donor mucus.

The SCMC test: a accurate indicator for spermatozoal antibodies

Eighteen couples (12.9%) were selected from a group of 138 infertile couples for a special study about the reliability of the SCMC test, when compared with spermantibody titres in the cervical mucus and or seminal plasma and corticosteroides as treatment for immunologic infertility. It can be demonstrated that there exists a reliability of the SCMC test as an immunologic assay for sperm antibody activity in the semen and the cervical mucus.

Expression of immunity to intravaginal herpes simplex virus type 2 infection in the genital tract and associated lymph nodes

Herpes simplex virus type 2 is a human venereal pathogen which causes lethal neurological illness after intravaginal inoculation into BALB/cJ mice. In the present studies, we demonstrate that intravaginal vaccination with an attenuated strain of this virus, which possesses a partial deletion of the thymidine kinase gene, rapidly induced durable immunity to lethal intravaginal challenge with wild-type virus. Such immunity was characterized by a dramatic hyperplasia of genital lymph nodes and a significant reduction in wild-type virus replication and spread from the genital tract following lethal challenge. Of greater importance, immunity to lethal wild-type virus challenge in the genital tract was transferrable to non-immune mice with genital lymph node cells prepared 1 week after intravaginal vaccination but was not transferrable with serum or cells from other lymphoid organs tested at this time. The adoptive transfer of anti-viral immunity to wild-type challenge was also characterized by a diminution in wild-type virus replication and spread from the genital tract. These results suggest that an important component of cellular immunity to genital pathogens may be antigenic stimulation of genital lymph nodes.

Sperm cervical mucus contact test and immunobead test for sperm antibodies

Twenty-five patients were studied for the presence of sperm antibodies in their cervical mucus and seminal plasma. The sperm cervical mucus contact test (SCMC) and the immunobead test (IBT) were used to evaluate sperm antibody activity. A close correlation was found between the results of the SCMC and IBT tests, and it was concluded that both techniques can be regarded as good indicators of sperm antibodies.