The incidence of sperm-associated immunoglobulin and C3, the third component of complement, in infertile men**Supported in part by a grant from the Andrew W. Mellon Foundation and by NIH grant CA-15236.††Presented in part at the Annual Meeting of the American Society of Andrology, February 23 to 25, 1982, Hilton Head Island, South Carolina

Anti-sperm Antibodies as an Increasing Threat to Male Fertility: Immunological Insights, Diagnostic and Therapeutic Strategies

It is a fact that sperm possess antigenic properties. Substantial scientific research suggests that specific antibodies that attach to sperm antigens can induce infertility in both humans and other species. Antisperm antibodies (ASA) represent a significant etiology of infertility in humans, leading to immunoinfertility. The association between ASA and infertility is multifaceted. The observation of sperm agglutination, although not conclusive for the diagnosis of immunological infertility, may suggest the presence of ASA. Nevertheless, ASA may also manifest in the lack of any sperm agglutination. Managing ASA from an andrological perspective depends on the underlying cause and the specific approaches healthcare professionals adopt. The precise etiology of male infertility resulting from ASA remains unclear. Current research has examined the impact of ASA and its prevalence among infertile males to understand the relationship between ASA and changes in semen parameters. However, the findings have been inconclusive. Numerous techniques have been documented for the management of immunoinfertility. This review examines the importance of ASA in the context of infertility, encompassing the postulated mechanisms underlying the development of ASA, the various assays employed for detecting them, and the available treatments.

Staphylococcal infections and infertility: mechanisms and management

Infertility is a subject of worldwide concern as it affects approximately 15% of couples. Among the prime contributors of infertility, urogenital bacterial infections have lately gained much clinical importance. Staphylococcal species are commensal bacteria and major human pathogens mediating an array of reproductive tract infections. Emerging evidences are 'bit by bit' revealing the mechanisms by which Staphylococci strategically disrupt normal reproductive functions. Staphylococcal species can directly or through hematogenous routes can invade the reproductive tissues. In the testicular cells, epididymis as well as in various compartments of female reproductive tracts, the pathogen recognition receptors, toll-like receptors (TLRs), can recognize the pathogen-associated molecular patterns on the Staphylococci and thereby activate inflammatory signalling pathways. These elicit pro-inflammatory mediators trigger other immune cells to infiltrate and release further inflammatory agents and reactive oxygen species (ROS). Adaptive immune responses may intensify the inflammation-induced reproductive tissue damage, particularly via activation of T-helper (Th) cells, Th1 and Th17 by the innate components or by staphylococcal exotoxins. Staphylococcal surface factors binding with sperm membrane proteins can directly impair sperm functions. Although Staphylococci, being one of the most virulent bacterial species, are major contributors in infection-induced infertility in both males and females, the mechanisms of their operations remain under-discussed. The present review aims to provide a comprehensive perception of the possible mechanisms of staphylococcal infection-induced male and female infertility and aid potential interventions to address the lack of competent therapeutic measures for staphylococcal infection-induced infertility.

Latheef S, Sharun K, Khurana SK, K. A, Tiwari R, Bhatt P, K. V, Chaicumpa W. Role of Antisperm Antibodies in Infertility, Pregnancy, and Potential forContraceptive and Antifertility Vaccine Designs: Research Progress and Pioneering Vision

Sperm of humans, non-human primates, and other mammalian subjects is considered to be antigenic. The effect of changes in autoimmunity on reproductive cells such as spermatozoa and oocytes play a critical but indistinct role in fertility. Antisperm antibodies (ASAs) are invariably present in both females and males. However, the degree of ASA occurrence may vary according to individual and gender. Although the extent of infertility due to ASAs alone is yet to be determined, it has been found in almost 9-12% of patients who are infertile due to different causes. Postcoital presence of spermatozoa in the reproductive tract of women is not a contributory factor in ASA generation. However, ASA generation may be induced by trauma to the vaginal mucosa, or by anal or oral sex resulting in the deposition of sperm inside the digestive tract. It is strongly believed that, in humans and other species, at least some antibodies may bind to sperm antigens, causing infertility. This form of infertility is termed as immunological infertility, which may be accompanied by impairment of fertility, even in individuals with normozoospermia. Researchers target ASAs for two major reasons: (i) to elucidate the association between ASAs and infertility, the reason ASAs causes infertility, and the mechanism underlying ASA-mediated infertility; and (ii) to assess the potential of ASAs as a contraceptive in humans in case ASAs influences infertility. Therefore, this review explores the potential application of ASAs in the development of anti-spermatozoa vaccines for contraceptive purposes. The usefulness of ASAs for diagnosing obstructive azoospermia, salpingitis, and oligoasthenoteratozoospermia has been reviewed extensively. Important patents pertaining to potential candidates for spermatozoa-derived vaccines that may be utilized as contraceptives are discussed in depth. Antifertility vaccines, as well as treatments for ASA-related infertility, are also highlighted. This review will address many unresolved issues regarding mechanisms involving ASAs in the diagnosis, as well as prognoses, of male infertility. More documented scientific reports are cited to support the mechanisms underlying the potential role of ASA in infertility. The usefulness of sperm antigens or ASAs (recombinant) in human and wild or captive animal contraceptive vaccines has been revealed through research but is yet to be validated via clinical testing.

Clinical associations and mechanisms of action of antisperm antibodies

OBJECTIVE

To review and critique the current English literature describing the effects of antisperm antibodies (ASA) on mammalian fertility.

DESIGN

A comprehensive English language literature was searched using Medline and by hand-searching. Emphasis was placed on clinically relevant articles.

RESULT(S)

Results from the studies were extrapolated and the effects of ASA on fertility described.

CONCLUSION(S)

Antisperm antibodies may interfere with fertility. Not all ASA cause infertility. Current tests cannot differentiate the infertility-related ASA from those that do not interfere with infertility, because the antigenic specificities of these ASA are not known. The antigens which the infertility-related ASA must be characterized to allow an accurate detection and proper treatment for couples with ASA.

Quantification of C3 and C4 in infertile men with antisperm antibody in their seminal plasma

PROBLEM

Previous studies showed that some infertilities are caused by antisperm antibodies (ASAs). It was shown that some major complement (C) components are present in seminal fluid. Due to the role of C in the pathogenesis of ASAs, the existence and amount of two key C components (C3 and C4) were investigated in seminal plasma (SP).

METHOD OF STUDY

Single radial immunodiffusion assay and a sandwich-type enzyme-linked immunosorbent assay (ELISA) were used for C3 and/or C4 quantification, respectively, in serum and SP, and the tray agglutination test was used for ASA detection in 12 fertile and 53 infertile men (18 ASA-positive [ASA+] and 35 ASA-negative [ASA-] men).

RESULTS

Of the 18 ASA + infertile men, 61.11% had positive C3, whereas 27.77% showed positive C4 levels. ASA + infertile men showed significant differences in seminal plasma C3 mean values compared with ASA- infertile (P < 0.01) and fertile (P < 0.05) men, but the seminal plasma C4 values only showed differences compared with ASA- infertile men (P < 0.05). No significant differences were observed in serum C3 and/or C4 levels of ASA+ infertile men compared with other groups. No significant correlation was found between ASA titer and C3 and C4 levels in SP. A significant correlation existed between SP and serum C3 levels of ASA+ (r = 0.522, P < 0.01) and ASA- (r = 0.451, P < 0.01) infertile men, but no correlation was observed between C4 levels.

CONCLUSIONS

In the presence of ASAs, the C system has no definitive activity in blood serum or outside the male genital tract. In SP, and in association with ASAs, C has no lytic activity by the classical pathway. The excess of C3 in SP of ASA+ infertile men may participate in other C-mediated activities in the male reproductive tract.

Prevalence of sperm bound antibodies in infertile men with varicocele: the effect of varicocele ligation on antibody levels and semen response

An increased level of antisperm antibodies has been demonstrated in infertile men with varicocele compared with normal fertile men, suggesting a possible cause and effect relationship. To evaluate the possible etiological role of antisperm antibodies in varicocele patients, we performed a prospective study of 32 infertile men undergoing varicocele ligation. Semen analyses and antisperm antibodies as measured by the immunobead test were performed preoperatively and postoperatively at 3 and 6 months. Of the infertile men with varicocele 28% had a positive immunobead test compared with 0% of normal fertile men. The average total motile sperm count was significantly different (p < 0.05, 2-tailed t test) for 9 varicocele patients with sperm-bound antibody (3.2 x 10(6)) compared with 23 without antibody (8.4 x 10(6)). Postoperatively, 68% of all patients exhibited improved semen parameters, with no change in antibody status in either group. Among the antibody positive group 71% showed an increase in motile sperm per ml. of 2.8 x 10(6) to 17.2 x 10(6) (525% increase, p < 0.05), while in the antibody negative group 67% showed an increase of 3.8 x 10(6) to 24.9 x 10(6) (553% increase, p < 0.05). Our study suggests that there is an increased incidence of sperm-bound immunoglobulin in infertile varicocele patients and an apparent adverse effect on semen parameters in these patients. However, the presence of sperm-bound immunoglobulin did not affect the percentage response to surgical correction, nor can we postulate an immunological mechanism as a major etiological factor in varicocele induced infertility.

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.

Risk factors for antisperm antibodies in infertile men

PROBLEM

The prevalence of anti-sperm antibodies (ASAs) in the general population is 0 to 2%; the prevalence in infertile men is much higher at 7 to 26%. However, the role of ASAs in male infertility remains controversial to date. Although several risk factors for ASA development have been defined (such as testicular torsion, varicocele, cryptorchidism, vasectomy, and genital tract infection), there are no specific indications for ASA testing.

METHOD

In order to examine if a single parameter exists identifying patients with elevated ASA titers, serum ASA testing was performed with an enzyme-linked immunosorbent assay (ELISA) in 226 consecutive male patients. The new assay, synchron ELISA (Synelisa) used in our study represents a new type of ELISA without fixation of the sperm surface antigens by formaldehyde or glutaraldehyde. Therefore, the quantitative assay is highly sensitive and reproducible since the structure of sperm surface antigens is not altered by the fixation process.

CONCLUSIONS

The prevalence of ASAs in this population was 14%, while the prevalence of the control group was 2.5%. Of all factors analyzed only a history of vasectomy, an acute epididymitis, and an abnormal result in the bovine mucus penetration test was associated with elevated ASA titers (P < .001). In addition, we could demonstrate a time related formation of ASAs in men after vasectomy.

Antispermatozoal antibody values after varicocelectomy

Although there are many causes of the production of antispermatozoal antibodies, there are still unknown aetiological factors. Antispermatozoal antibodies were investigated in the postoperative period in 25 infertile men with varicocele whose antispermatozoal antibody tests were negative in the preoperative period. Antispermatozoal antibodies were found in the serum in 4 of the 25 (16%) infertile men after varicocele operation. Postoperative genital infections were detected in 6 patients and antispermatozoal antibodies were present in only 2 of them. The correlation between these antibodies and varicocele has been demonstrated but there is no report on the association of antibodies with varicocelectomy in the literature to date.

Prevalence of antisperm antibodies by SpermMARtest in subjects undergoing a routine sperm analysis for infertility

To evaluate the prevalence of antisperm antibodies (ASA) attached to the sperm plasma membrane in male partners of infertile couples, the binding of latex particles to spermatozoa was investigated using SpermMARtest, included routinely in semen analysis. A total of 860 men were examined, who were referred consecutively for semen analysis. Of these, 750 men were referred because of infertility (0.6-10 years in duration) whereas 110 were volunteers with a history of previous fertility. Samples were assessed by the SpermMARtest kit using latex particles sensitized with human IgG. Sperm-latex binding was read after 3 min and samples scored as negative, positive or highly positive when < 10, > 10-40, or > 40% binding occurred, respectively. Of the samples 132 (17.3%) were excluded because of azoo- or severe oligo-asthenozoospermia. IgG attached to spermatozoa were detected in nearly 13% of semen samples from the infertile population and in one of 110 fertile men (0.9%). From the infertile group, 6.2% of samples showed > 40% binding, and 6.7% intermediate binding, with an overall ASA prevalence of 12.9% in subjects undergoing semen analysis for infertility.

Varicocele-related infertility is not associated with increased sperm-bound antibody

Immunological factors have been implicated as a cause of unexplained infertility. Previous studies have demonstrated increased levels of sperm-bound antibody in infertile men with varicoceles and have postulated their role in varicocele-related infertility. However, these studies were performed using an enzyme-linked immunosorbent assay. We evaluated retrospectively 111 male patients referred for infertility using a direct immunobead assay. Of the patients 29 had grade II or III varicoceles (that is palpable or easily visualized) and 82 were without varicocele. Four patients who had undergone vasovasostomy were included as controls for the assay. A direct immunobead assay was performed for isotype IgG and IgA sperm-bound antibody using a standard protocol. A computerized semen analysis was also performed. Greater than 20% binding, excluding tail tip activity, was considered significant. Of 29 patients with and 82 without a varicocele significant binding was identified in 5 (17%) and 9 (11%), respectively. Chi-square statistical analysis did not reveal this difference to be significant (p < 0.05). All 4 vasovasostomy patients demonstrated significant binding. We conclude from this study that infertile men with varicoceles do not demonstrate significantly increased levels of sperm-bound antibody compared to infertile controls and, therefore, sperm-bound antibody does not appear to have a significant role in varicocele-related infertility.

Membrane cofactor protein (MCP, CD46) in seminal plasma and on spermatozoa in normal and "sterile" subjects

A sperm protein of molecular mass 43 kDa (the spermatozoa membrane cofactor protein, smMCP) and a seminal plasma protein of 60 kDa (ssMCP) were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) followed by immunoblotting with four monoclonal antibodies (mAb) against membrane cofactor protein (MCP, CD46). These proteins served as factor I cofactors for the cleavage of methylamine-treated C3 (C3ma), the activity of which was blocked by M75, an MCP cofactor-activity-blocking mAb. Thus, these semen proteins are antigenic and functional homologous of MCP. On SDS-PAGE analysis these MCP migrated as single-band proteins which differed from the two-band forms of MCP expressed on other cells. smMCP was N-glycosylated but not O-glycosylated, while ssMCP was O-glycosylated: after deglycosylation of these proteins bands were detected at 38-40 kDa and 43 kDa on SDS-PAGE, respectively. These semen MCP are therefore, structurally different from the conventional MCP. ssMCP in both normal and "sterile" subject groups was determined by sandwich enzyme-linked immunosorbent assay. Seminal plasma in the two groups contained 250-700 ng/ml ssMCP. The difference between the two groups was marginal, although samples from normal subjects tended to show higher concentrations of ssMCP than samples from "sterile" subjects. No molecular difference was observed with ssMCP and smMCP in the two groups by SDS-PAGE/immunoblotting analysis. Immunohistochemical analysis suggested that MCP was positive in glandular epithelial cells and the lumen of the prostate, and in most intra-lumen cells of the testis. Using antibody M177, solubilized prostate and testis were analyzed by immunoblotting and compared with other cell MCP. The major band of MCP in the testis, but not in the prostate, was of 60 kDa, which aligned with ssMCP. No band of testis or prostate MCP, however, aligned with smMCP. ssMCP may be produced in the testis, while the origin of smMCP remains unknown. We hypothesize that ssMCP is important in the survival of spermatozoa, protecting them against local secretion of immunoglobulin and complement in the female genital tract, and that smMCP, which is expressed on acrosome-reacted spermatozoa, plays an essential role in the interaction of spermatozoa with oocytes.

Characterization of a cDNA clone coding for human testis membrane cofactor protein (MCP, CD46)

Membrane cofactor protein (MCP) is a complement regulatory protein that acts as a cofactor for the cleavage of C3b and C4b by the serine protease factor I. We have previously reported the characterization of a functional MCP molecule on the acrosomal membrane. This protein migrated as a single band with a molecular weight of 40,000 Da, which is 10,000-20,000 Da smaller than the known MCP molecules, and is devoid of N- and O-linked sugars. We have proposed that the difference in molecular weight resulted from the lack of sugars. To investigate if this is due to the absence of glycosylation sites, we have characterized a cDNA clone from a human testis cDNA library. This cDNA corresponds to a peculiar MCP form previously described, which is characterized by the presence of the serine/threonine/proline-rich exon C (STPC) and the cytoplasmic tail known as CYT2, and we conclude that the absence of mature oligosaccharide of the sperm MCP cannot be totally attributed to a defect of N- and O-glycosylation sequences but rather reflects an alteration of the mechanisms of glycosylation in spermatozoa. The presence of functional MCP on the acrosomal membrane, as well as the other complement regulatory protein, decay-accelerating factor, strongly suggests that these proteins may act concomitantly to protect the acrosome-reacted spermatozoa from the attack of the complement present in the female genital tract.

Lack of complement activation in the seminal plasma of men with antisperm antibodies associated in vivo on their sperm

A specific and sensitive "sandwich"-type radiolabeled antiglobulin assay (RAA) using monoclonal anti-human C5b-9 neoantigen and polyclonal anti-human C5b-9 was used to evaluate the presence of the in vivo product of human complement (C) activation (SC5b-9) in the seminal plasma (SP) of 19 fertile and 61 infertile men. SP SC5b-9 was detectable in 7 (8.7%; 1 fertile and 6 infertile men) of the 80 men with a range of 10 to 175 ng/ml. Levels of SP SC5b-9 in other men were below the limit of detection (less than 10 ng/ml). Of the 33 infertile men with sperm-associated immunoglobulin (Ig) G and/or IgA, 27 (82%) had undetectable levels of SP SC5b-9 immunoreactivity. There was no correlation between the SP SC5b-9 levels and the degree of sperm-associated IgG (r = 0.086) or IgA (r = 0.23) activity. However, significant deposition of sperm-bound C5b-9 due to autologous C activation was demonstrated by flow cytometry of donor sperm treated with sera from autoimmune men with ASA in their sera and on their sperm. These findings suggest that sperm-bound Ig cannot activate C in SP.

A comparison of the usefulness of SpermMar and immunobead tests for the detection of antisperm antibodies

We compared two testing protocols designed to detect immunoglobulin (Ig) G antibodies on sperm surfaces: (1) SpermMar (Ortho, Raritan, NJ) and (2) Immunobead Testing (Biorad, Richmond, CA). The standard SpermMar (SPMAR) protocol (direct test of unwashed semen) was performed with 47 ejaculates and found to be more sensitive than Immunobead Testing (IBT) on washed sperm, detecting five samples with greater than or equal to 30% bead binding, all of which by IBT had less than 20% bead binding. In contrast, when SPMAR was performed on washed sperm or with an indirect antibody transfer from serum or seminal plasma, SPMAR results gave mostly low values for bead binding in comparison with IBT. Our data suggest that SPMAR be used only in direct assays employing unwashed ejaculates, that it can be easily incorporated into routine semen analysis as a screening test, and that positive results should be confirmed by IBT (IgG and IgA).

SpermCheck: a simplified screening assay for immunological infertility

SpermCheck (Bio-Rad Laboratories, Hercules, CA), a new screening test for regional surface antibodies on motile sperm, uses monodispersed latex microspheres of uniform size as a vehicle to link rabbit antihuman immunoglobulins (IgA, IgG, IgM) and provides both negative and positive control sera, as well as sufficient buffer for sperm preparation in ambient CO2 atmosphere. When compared with reference data available for the immunobead test (IBT), the direct protocol (semen) for SpermCheck yielded 94.4% sensitivity with 100% specificity; the indirect protocol (serum) provided a sensitivity of 100% with 94.7% specificity. The microspheres of SpermCheck maintain a nearly uniform concentration per volume, with none to negligible clumping. The greater difference between the optical densities of latex and cytoplasm allows use of a light microscope for the rapid assessment of the percent of regional binding rather than the phase-contrast microscope required for the IBT. SpermCheck eliminates many difficulties encountered with the IBT, making SpermCheck a convenient screening assay for use in the physician's office.

Correlation of sperm-bound immunoglobulins with impaired semen analysis in infertile men with varicoceles

Sperm-bound immunoglobulins were found in 27 (32%) of 84 infertile men with palpable varicoceles. These men were divided into two groups based on the presence (group I; 32%) or absence (group II; 68%) of sperm-bound immunoglobulins, as measured by an enzyme-linked immunosorbent assay. Circulating antisperm antibodies were identified in 52% of patients with sperm-bound immunoglobulins and 14% of group II patients. The presence of sperm-bound immunoglobulins was associated with a small but significant decrease in both sperm concentration and motility. Sperm-bound immunoglobulins are present in a greater percentage of infertile men with varicoceles than infertile men without varicoceles. Their presence may be a marker for damage to the seminiferous epithelia in men with varicoceles and may also contribute to varicocele-associated infertility.

The relationship of circulating antisperm antibodies to sperm surface antibodies in infertile men

The correlation between the amount and location of antisperm antibody binding to the sperm surface and the level measured in the serum has not been previously reported. Hence, the value and limitations of screening blood sera from men with suspected immunologic infertility are not currently known. In this study 70 paired sera and semen samples were assayed by the immunobead test (IBT). A screening protocol for blood sera was constructed to be 100% sensitive for detecting semen specimens with 20% or more of sperm binding IgG or IgA immunobeads. The specificity of this screening protocol was determined to be 79%. Serum IgA was not a good predictor of IgA on the sperm surface. The true positive predictive rate for antisperm antibodies on the sperm surface using circulating antisperm antibodies as a screening assay was estimated to be as low as 35%. There was little correlation between the site of immunobead binding following passive antibody transfer from patients' sera to donor sperm and the site of naturally occurring antibodies on the patients' sperm surface. Although direct assessment of antibodies on the sperm surface is preferred, these data suggest that serum IgG alone can be used as a sensitive screening assay for antisperm antibodies in men. A positive screen dictates that a direct assay on semen should be performed.

Simple radioimmunobinding assay for quantitation of sperm antibodies of IgG immunoglobulin class

The immunobead test (IBT) is an excellent test for initial sperm antibody screening and evaluation but is impractical when used to quantitate antibody levels using a twofold dilution series. The aim of this study, therefore, was to develop a relatively simple radioimmunobinding assay that would allow quantitation of sperm antibodies of IgG immunoglobulin class, which predominate in male sera. [125I]-Protein G was chosen as the radioligand because it binds to all IgG subclasses, but not to IgA or IgM. The results of the investigation indicate that the [125I]-protein G assay (PGA) allows efficient quantitation of sperm antibodies, as evidenced by a highly significant (P less than .0001) correlation (Spearman's, Rs = 0.94) between the PGA results and IgG-IBT titres.

How should sperm antibody tests be used clinically?

Immunoglobulin-specific assays are currently available for detection of patients with antibody-mediated infertility. Care must be taken in insuring that the correct immunoglobulin class is assayed, the assay is directed to the possible interaction of antibodies and sperm in the male or female genital tract, and the antigen employed will not detect antibodies against antigens not found on the plasma membrane of living sperm.

An improved immunobead test procedure for detecting sperm antibodies in serum

In order to improve the efficiency of IBT screening of sera for sperm antibodies, the use of immunobeads with attached rabbit antibodies directed against whole human immunoglobulin (IBT-GAM) was investigated and compared with the use of separate immunobeads specific for each of the main immunoglobulin classes (IBT-IgG, IBT-IgA, IBT-IgM). Sera found positive by the IBT-GAM procedure were then tested by IBT-IgG, -IgA, and -IgM procedures to determine the immunoglobulin class or classes of the sperm antibody. The new procedure is much more efficient for screening larger batches of sera and gives results identical with those from the old procedure when greater than or equal to 50% sperm coating is used as criterion of positivity. We now use the IBT-GAM procedure for initial screening of all sera, followed by further testing of positive sera on the same preparation to determine the immunoglobulin class or classes of the antibody.

Incidence of sperm-associated immunoglobulins in infertile men with suspected autoimmunity to sperm

Semen samples from 120 infertile men with suspected autoimmunity to sperm were investigated by a direct immunobead test (IBT). Fifty-three (44%) of them had 10% or more motile sperm coated with anti-IgG and/or anti-IgA immunobeads. Both classes of immunoglobulins were found to be present in 88.7% of the antibody positive ejaculates. These sperm-bound Igs were associated with sperm autoagglutination in 80% of the ejaculates and with decreased sperm penetration into cervical mucus in 97.6% of the cases. The close correlation found between the IBT results and the occurrence of antisperm antibodies in serum and in seminal plasma suggests that sperm-bound Ig's are sperm-specific antibodies. It is concluded that the direct IBT is not only a reliable screening test for sperm antibodies but is also a relevant test to determine whether these antibodies exert an influence on male fertility.

Quantitation of sperm bindable IgA and IgG in seminal fluid

Seminal fluid and serum from 95 infertile males were assayed for sperm bindable immunoglobulins using an indirect ELISA with whole target sperm. The ELISA method was compared to seminal fluid and serum immobilization and agglutination assays (functional assays). In this infertile group, the ELISA assay was positive in 22% of seminal fluids (greater than 1.2 fg IgA/sperm and greater than 0.3 fg IgG/sperm). The seminal fluid antibodies were IgA and had an accompanying elevated IgG component in 78% of patients. There was a 96% correlation between negative seminal fluid functional assays and negative ELISA, and a 95% correlation between positive seminal fluid functional assays and positive ELISA. Positive serum sperm antibody tests were found in 71% of the infertile males with positive seminal fluid sperm antibodies, but 29% of the infertile males with strongly positive IgA seminal fluid sperm antibodies showed normal levels of serum sperm antibodies by either ELISA or functional assays. The ELISA method gives reproducible quantitation of sperm antibodies in seminal fluid and correlates well with accepted functional assays. Comparisons with serum sperm antibody assays suggests that seminal fluid sperm antibody analysis complements the serum analysis of sperm antibodies.

Failure to identify HLA ABC and Dr antigens on human sperm

An indirect radiolabeled antiglobulin assay (IRAA), adsorption procedures, and an indirect immunofluorescent assay using cytofluorometry (IFAA) failed to identify HLA ABC or D/Dr antigens associated with untreated human sperm or human sperm exposed to capacitating conditions. Two monoclonal clones against HLA ABC and two clones against Dr antigens were utilized. Test results in the IRAA were not different regardless of whether sperm from fertile men or human red blood cells were employed in the IRAA. However, there were highly significant differences in the IRAA between the HLA antigen expression of human sperm and leukocytes. If the antihuman HLA monoclonal antibody was preadsorbed with 25 X 10(6) sperm, there was no diminution in the ability of the adsorbed antibody to identify HLA antigens on leukocytes; however, preadsorption with 2.5 X 10(6) leukocytes reduced the activity of the monoclonal antihuman HLA antibody to levels equivalent to background activity.

Detection of sperm antibodies in semen using the immunobead test: a survey of 813 consecutive patients

The aims of this investigation were to determine the incidence of sperm-bound antibodies in an unselected infertile population and also to further evaluate the immunobead test (IBT) with respect to specificity and reproducibility. The results of the survey showed that 7.8% of 813 men had antibodies of IgG and/or IgA class bound to the surface of at least 20% of their motile spermatozoa. The results of crossed-inhibition tests with purified human immunoglobulins and comparison of the IBT results with the sperm-immobilization test (SIT) in serum and sperm agglutination in semen suggested that the IBT is an immunologically specific test for sperm antibodies. Comparison of repeat tests on 123 patients showed that the IBT is reproducible in 97.5% of cases. There was no difference in mean count, percentage motile, or morphology between the groups of patients with positive or negative IBT results. The incidence of sperm agglutination was significantly (Chi-squared, p less than 0.001) higher in the positive IBT group. The results of this investigation therefore suggest that the IBT is an excellent test for routine screening of men for sperm antibodies.

Effect of male antisperm antibodies on sperm fertilizability in vitro

Male partners of 129 infertile couples were evaluated for antisperm factors by using the hamster zona-free ovum (HZFO) test. Sperm-agglutinating activity and antifertilization factors were assessed by adding the male partner's serum to donor sperm in the HZFO-serum antibody (HA) test. When patient's HZFO scores were less than 20% of the hamster ova fertilized, fertilization by patient's serum in the HA test. Of 13 samples that failed to fertilize any of the hamster ova, nine were antibody-negative, of which seven had at least one extremely deficient sperm parameter. Of the four men with positive serum, two had normal and one had abnormal semen (one did not have a complete semen analysis). These data emphasize the need to test male partners for a decline in fertilizing capacity, which is frequently related to the presence of serum antisperm factors. These tests could be used to identify paternal and maternal components (sperm and serum) that may hinder fertilization in fertilization programs.

Identification of antibody-laden sperm by cytofluorometry

A direct assay for measuring sperm-associated immunoglobulin G (IgG) and an indirect assay for measuring IgG plasma antisperm antibodies were devised utilizing fluorescein-labeled antihuman IgG and a fluorescein-activated flow cytometer. The method singularly analyzed Ig attached to the surface of sperm because sperm and nonsperm cells were separately assessed. The direct assay technique results correlated with results from a previously reported direct radiolabeled antiglobulin assay. As few as 100,000 sperm are required in the indirect method; the sensitivity of the indirect technique corresponded with that of a previously reported indirect radiolabeled antiglobulin assay.

Relationship between genital tract infections, sperm antibodies in seminal fluid, and infertility

To explore possible relationships between genital tract infections, sperm antibodies, and infertility, seminal fluid from 100 men was analyzed. Sperm antibodies, measured by an enzyme-linked immunosorbent assay, were detected in 14 of 29 men (48%) with culture-positive asymptomatic infections, 8 of 17 men (47%) with a history of prostatitis or urethritis, 11 of 33 men (33%) with either a varicocele or an abnormal semen analysis, and only 1 of 21 men (5%) with no infection and a normal semen analysis. The incidence of sperm antibodies in the men with infections or urethritis or prostatitis was significantly higher than in the control subjects (P less than 0.005). The sperm antibody isotype in men with infections was mainly IgA, although IgG or IgM were also sometimes present. Of the men with asymptomatic infections, urethritis or prostatitis, significantly (P less than 0.025) more men without sperm antibodies (12 of 24, 50%) were fertile than were those with sperm antibodies (3 of 22, 13%). Men with genital tract infections have a high incidence of antibodies, reactive with spermatozoa, which is associated with reduced fertility.