Anti-sperm antibodies, detected by agglutination, immobilization, microcytotoxicity and immunobead-binding assays

Decreased levels of genuine large free hCG alpha in men presenting with abnormal semen analysis

BACKGROUND

The pregnancy hormone human chorionic gonadotropin (hCG) and its free subunits (hCG alpha, hCG beta) are produced in the male reproductive tract and found in high concentrations in seminal fluid, in particular hCG alpha. This study aimed to elucidate changes in peptide hormone profiles in patients showing abnormal semen analyses and to determine the genuineness of the highly abundant hCG alpha.

METHODS

Seminal plasma was obtained from 45 male patients undergoing semen analysis during infertility workups. Comprehensive peptide hormone profiles were established by a panel of immunofluorometric assays for hCG, hCG alpha, hCG beta and its metabolite hCG beta core fragment, placental lactogen, growth hormone and prolactin in seminal plasma of patients with abnormal semen analysis results (n = 29) versus normozoospermic men (n = 16). The molecular identity of large hyperglycosylated hCG alpha was analyzed by mass-spectrometry and selective deglycosylation.

RESULTS

hCG alpha levels were found to be significantly lower in men with impaired semen quality (1346 +/- 191 vs. 2753 +/- 533 ng/ml, P = 0.022). Moreover, patients with reduced sperm count had reduced intact hCG levels compared with normozoospermic men (0.097 +/- 0.022 vs. 0.203 +/- 0.040 ng/ml, P = 0.028). Using mass-spectrometry, the biochemical identity of hCG alpha purified from seminal plasma was verified. Under non-reducing conditions in SDS-PAGE, hCG alpha isolated from seminal plasma migrated in a manner comparable with large free hCG alpha with an apparent molecular mass (Mr, app) of 24 kDa, while hCG alpha dissociated from pregnancy-derived holo-hCG migrated at approximately 22 kDa. After deglycosylation with PNGase F under denaturing conditions, all hCG alpha variants showed an Mr, app of 15 kDa, indicating identical amino acid backbones.

CONCLUSIONS

The findings indicate a pathophysiological relevance of hCG, particularly its free alpha subunit, in spermatogenesis. The alternative glycosylation pattern on the free large hCG alpha in seminal plasma might reflect a modified function of this subunit in the male reproductive tract.

Sperm surface antigens and the prospects for contraceptive vaccine development

It has been estimated that 500 million couples world-wide have no access to contraception and that approximately 20% of births between 1995 and 2000 will be unwanted. Such statistics have important implications for the rate of world population growth and the possibility of maintaining a sustainable population. Although political change and the empowerment of women across the world will help address these issues, it will also be important to increase the availability of contraceptives; not only the modalities that are in current use, but also novel methods that will satisfy needs that are presently unfulfilled. One such alternative could be a vaccine targeting the human spermatozoon.

Human chorionic gonadotropin (hCG) in the male reproductive tract

Normal hypothalamic-pituitary testicular and prostatic functions are essential for maintenance of male fertility, whereby glycoprotein hormones (GPH) as well as androgens are major endocrine and local regulators. We have investigated whether the GPH human chorionic gonadotropin (hCG) and the free alpha and beta subunits thereof are produced in the target organs themselves and potentially act as auto/paracrine modulators of fertility. Immunofluorometric assays (IFMAs) based on our panel of highly selective monoclonal antibodies, immunohistochemistry (IHC), confocal laser scanning microscopy (CLSM) and 1- and 2D gel electrophoreses with subsequent western blotting have been utilized for the detection of hCGalpha, hCGbeta and its metabolite hCGbeta core fragment (cf) in human testis, prostate and seminal plasma. Both organs synthesize hCGalpha and hCGbeta, which are subsequently detectable at high concentrations in seminal plasma of healthy probands (n=17): hCGalpha 2630+/-520 ng/mL (mean+/-S.E.M.), hCGbeta 2+/-0.28 ng/mL, hCGbetacf and hCG 0.19+/-0.039 ng/mL. These parameters significantly exceed physiological values, e.g. ten thousand-fold in the case of hCGalpha, in serum of young men (n=20): hCGalpha 0.142+/-0.054 ng/mL (mean+/-S.E.M.), hCGbeta 0.05 ng/mL and hCG 0.004+/-0.003 ng/mL. Levels of these markers were not correlated with sperm counts. Of all body fluids including those of pregnant women seminal plasma is the richest physiological source for genuine free i.e. non-dissociated GPHalpha (M(r,app) 23k) which may even appear as di- or tetramers. Its concentration is similar to that observed in maternal serum (weeks 10-12 of gestation) and in extra-embryonic coelomic fluid. In contrast to those fluids where ratios of free subunits to hCG are in the range of 1:100 highly inverse ratios in the range of 10.000:1.000:1 were observed for hCGalpha:hCGbeta:hCG in seminal plasma. hCGalpha is not derived from heterodimeric GPH suggesting hCG-independent functions of hCGalpha and hCGbeta in male and female fertility.

Differential extraction and enrichment of human sperm surface proteins in a proteome: identification of immunocontraceptive candidates

The objective of this study was to discover previously unknown human sperm surface proteins that may be candidate contraceptive vaccinogens. To this end, methods of concentrating human sperm proteins for microsequencing by mass spectrometry were used, which increased the likelihood of identifying surface proteins. Vectorial labeling, differential extraction and two-dimensional (2-D) gel electrophoresis were employed to identify and isolate proteins accessible at the cell surface. Percoll harvested or swim-up sperm were either solubilized directly or solubilized after surface labeling with sulfo-succinimidyl-6-(biotinamido)hexanoate (sulfo-NHS-LC-biotin). Comparisons were made of proteins extracted with four lysis buffers: (i) Celis buffer containing 9.8 M urea and 2% Igepal CA-630; (ii) 1% Triton X (TX)-100; (iii) 1.7% TX-114 followed by phase partitioning; or (iv) 1 M NaCl. Blots of proteins separated by high-resolution 2-D electrophoresis were probed with avidin and antibodies to known proteins specific for three domains: the sperm surface (SAGA-1), the acrosome (SP-10), and the cytoskeleton (alpha-tubulin). Celis buffer (45 min) extracted proteins from all three major compartments. However, a 20-s extraction in Celis buffer enriched for several proteins and enabled the identification of several novel peptides by mass spectrometry. Mild extraction with TX-100 or 1 M NaCl solubilized mainly membrane and acrosomal proteins, but not cytoskeletal proteins. Comparison of biotinylated proteins extracted by each method showed that the major vectorially labeled proteins solubilized by Celis buffer were also solubilized by TX-100, TX-114, and 1 M NaCl. Extraction with TX-114 followed by phase-partitioning significantly enriched hydrophobic surface proteins and aided resolution and isolation. Eight protein spots microsequenced following all these extraction methods proved to be novel sperm molecules.

HLA-DR and HLA-DQ gene typing of infertile women possessing sperm-immobilizing antibody

Thirty-eight infertile women, possessing sperm-immobilizing antibody (SIA), were examined for their HLA-DR and -DQ types using DNA obtained from peripheral blood cells. The typing of HLA-DR and DQ was performed by polymerase chain reaction sequence specific oligonucleotide probes (PCR-SSOP) and PCR-restriction fragment length polymorphism (RFLP), respectively. In comparison to the normal Japanese population, the SIA positive patient population had higher genes frequencies in HLA-DRB1*0901 (26.3 vs. 13.6%, P<0.005), DQB1*0602 (13.2 vs. 6.2%, P<0.05) and -DQB1*0303 (26.3 vs. 14.8%, P<0.01), but not in any HLA-DQA1 gene types by chi2 test. After Bonferroni correction, the high frequency of HLA-DRB1*0901 remained significant (P<0.05) and HLA-DQB1*303 was slightly significant (P<0.07) but no other genes had a gene frequency significantly higher than that of the normal Japanese population. HLA-DRB1*0901 and HLA-DQB1*0303 are very rare among Caucasians but characteristically high among Japanese. The high frequency of HLA-DRB1*0901 and DQB1*0303 genes in the Japanese population may account for higher frequency of sperm-immobilizing antibody in Japanese compared to other ethnic groups.

Determination of interleukin-11 in seminal plasma and elevated IL-11 in seminal plasma of infertile patients with urogenital infection

This study was conducted to confirm the presence of IL-11 in human seminal plasma, to show eventual differences between IL-11 concentration in fertile and infertile subjects, and to show if urogenital infection is a factor determining its elevation. Seminal plasma from 93 men obtained by masturbation was examined for the presence of IL-11 using an IL-11-specific sandwich ELISA. Semen samples were obtained from 93 men divided (1) into seven groups according to the etiological diagnosis of fertility and, (2) into two groups on the basis of normal or abnormal spermiogram. The correlation of amount of IL-11 in seminal plasma with some spermiogram parameters was statistically evaluated. There was a statistically significant difference between the groups (p = 0.0007) due to group infection of accessory genital glands, which presents the highest mean rank value as compared to all other groups. The group normal spermiogram had a mean value for IL-11 of 51.83, while the abnormal spermiogram was 66.30. This difference is not statistically significant (p > 0.05). There was no correlation between IL-11 levels and the variables of the spermiogram. These findings demonstrate IL-11 to be in seminal plasma, and elevated IL-11 levels are detected in infertile patients with urogenital infections.

Do autoantibodies to sperm reduce fecundity? A mini-review in historical perspective

PROBLEM

The paradox that early studies of antisperm antibodies in men showed a strong correlation between titers of circulating antibodies (essentially immunoglobulin [Ig] G) and reduction in conception rates, whereas more recent studies have indicated that the antifertility effect is mainly (or exclusively?) associated with IgA antibodies, impairing sperm migration through cervical mucus, was studied.

METHOD OF STUDY

Relevant literature focusing on antibodies on ejaculated sperm was analyzed.

RESULTS

Direct mixed antiglobulin reaction (MAR) and immunobead-binding tests are excellent and sensitive techniques for demonstrating antibodies of the IgG and IgA classes on sperm, and they have revealed that IgA antibodies are, with very rare exceptions, found only when IgG antibodies are also present. However, these tests tell little about the amounts of antibodies present, and attempts to measure quantitatively the amounts of Ig on sperm have indicated higher levels of IgA than IgG (despite the strongest MAR reactivities for IgG).

CONCLUSIONS

The patients with high levels of IgA to their sperm are mainly men with strong immune responses and, therefore, also high antibody titers in serum. Apparently, the locally produced IgA antibodies reach the sperm and occupy the binding sites before the main bulk of IgG reaches the seminal compartment with the prostatic fluid.

Detection of antisperm antibodies in seminal plasma by flow cytometry: comparison with the indirect immunobead binding test

OBJECTIVE

To compare flow cytometry with the established indirect immunobead binding test (IBT) for the detection of antisperm antibodies in seminal plasma.

DESIGN

A prospective, comparative study.

SETTING

University-based andrology unit.

PATIENT(S)

One hundred and fifty-eight men with suspected male factor subfertility.

INTERVENTION(S)

Seminal plasma samples were incubated with antisperm antibody-negative donor sperm. Surface-bound antibody was detected with fluorescence-labeled antihuman antibody in the flow cytometry assay or with immunobead-labeled antihuman antibody in the IBT.

MAIN OUTCOME MEASURE(S)

The percentage of sperm that tested positive for surface-bound antibody was determined in the two assays. Seminal plasma was antisperm antibody-positive when > or = 20% of the sperm were antibody-bound, and clinically significant levels were present when > or = 50% of the sperm were antibody-bound.

RESULT(S)

Of 71 samples that were negative by the IMT, 66 (93%) also were negative by flow cytometry. Of 63 samples that had > or = 50% immunobead binding, 55 had equivalent results by flow cytometry. Overall statistical analysis showed a good correlation between the two assays.

CONCLUSION(S)

There is a good correlation between the indirect IBT and indirect flow cytometry for the detection of antisperm antibodies in seminal plasma.

Quantitative determination of IgG and IgA on sperm from infertile patients with and without antisperm antibodies

Immunoglobulins on patients sperm were determined by an ELISA technique, modified from the RIA described by Haas and D'Cruz (Am J Reprod Immunol, 1989; 20:37-43), i.e., suspensions of washed sperm (40, 20, 10, and 5 mill/ml) were added to a dilution of peroxydase-labelled anti-IgG or anti IgA, and after incubation the supernatants were transferred to cups in microtrays, coated with IgG or IgA, respectively. After incubation and washing ELISA reaction was carried out. Known amounts of IgG and IgA were processed in the same way to obtain a standard curve, allowing the Ig on the sperm to be expressed in ng/mill sperm. Ejaculates with increased viscosity revealed high values, irrespective of MAR-results and in some cases the same was true for samples with large numbers of non-spermatozoal cells (NSC). However, among 48 samples from men from infertile couples with negative MAR, > 20 mill sperm/ml, normal viscosity, and a ratio between sperm and NSC > 5, the median for IgG was 0.2 ng/mill sperm, 90% had < or = 0.8 ng/mill sperm, and the highest value recorded was 1.9 ng/mill sperm. For IgA the median was 0.5 ng, 90% of the 47 samples contained < or = 1.9 ng, and the highest value was 3.1 ng/mill sperm. The values for sperm from patients with a positive MAR, but without free antibodies in seminal plasma, were generally within the normal range. In contrast, increased values were recorded for most of the patients with free antibodies in seminal plasma, up to 4.2 ng/mill sperm for IgG and up to 12.5 ng/mill sperm for IgA.

Changes in various antioxidant levels in human seminal plasma related to immunoinfertility

The present study was designed (1) to determine levels of antioxidant micronutrients in human seminal plasma, and (2) to evaluate the association between the concentrations of these antioxidants and the antisperm antibody titers in immunoinfertile men. To investigate this, the seminal plasma concentrations of antioxidant beta-carotene, lycopene, retinol, and alpha-tocopherol were measured by high-pressure liquid chromatography in 37 men (22 fertile and 15 immunoinfertile), aged 27 to 35 years. The SIT (sperm-immobilization technique), TAT (tray-agglutination technique), and IBT (indirect immunobead test) were used to evaluate the antisperm antibody titers. The levels of three antioxidants, namely, beta-carotene, lycopene, and retinol, were significantly (p = .01) decreased and the concentration of alpha-tocopherol was significantly (p = .002) increased in seminal plasma of immunoinfertile men as compared to the levels in fertile men. There was a significant linear correlation between the antisperm antibody titer and beta-carotene level measured by IBT (r = .561, p = .002), whereas no significant correlation was found with the other three seminal plasma antioxidants, namely, lycopene, retinol, and alpha-tocopherol levels. These results indicate, for perhaps the first time, the presence of antioxidants in local genital tract secretions of men. Modulation of their concentrations in immunoinfertile men and their correlation with the antisperm antibody titers strongly suggest the involvement of dietary antioxidants in male infertility, especially mediated through immunologic factors.

Levels of interferon-gamma and tumor necrosis factor-alpha in sera and cervical mucus of fertile and infertile women: implication in infertility

Concentrations of two immune cytokines, namely interferon-gamma (INF-gamma) and tumor necrosis factor-alpha (TNF-alpha), were determined in the sera and cervical mucus samples of fertile (n = 16), idiopathic infertile (n = 44), and immunoinfertile women (n = 45) to investigate their role, if any, in female infertility. Sera of idiopathic infertile women demonstrated significantly (P < 0.0001) higher levels of INF-gamma compared to those in fertile controls, whether expressed as pg/ml or pg/mg serum protein. Similarly, sera of immunoinfertile women demonstrated significantly (P = 0.0008) higher levels of INF-gamma compared to fertile controls and idiopathic infertile women. Cervical mucus of idiopathic infertile women also demonstrated significantly (P < 0.0001) higher concentrations of INF-gamma compared to those in fertile controls. Cervical mucus of immunoinfertile women demonstrated significantly (P < 0.0001) higher concentrations of INF-gamma compared to those in fertile controls and idiopathic infertile women. INF-gamma levels in serum did not significantly (P > 0.05) correlate (r = 0.12-0.43) with the concentrations in cervical mucus, when all the three groups were compared together. However, when the serum levels were compared with the cervical mucus concentrations by condition, only the idiopathic infertile group showed a significant (P = 0.005) correlation (r = 0.70). Serum levels of TNF-alpha did not differ significantly (P > 0.05) among three groups of women. Cervical mucus concentrations of TNF-alpha, however, varied among groups with levels being significantly (P = 0.04) higher-in idiopathic infertile women compared with fertile controls and in immunoinfertile women significantly (P = 0.0007) higher than in fertile controls as well as idiopathic infertile women. TNF-alpha levels in serum correlated (r = 0.65) significantly (P < 0.001) with the concentrations in cervical mucus when all the three groups were compared together or individually by infertility condition. These findings suggest the involvement of cytokines in infertility, and thus may have potential applications in diagnosis and treatment of female infertility.

Enhanced levels of colony stimulating factor-1 (CSF-1) in sera and seminal plasma of antisperm antibody-positive infertile men

This investigation was carried out to examine the levels of CSF-1 in sera and seminal plasma of fertile, immunoinfertile, and male factor-infertile men in order to study the role of CSF-1 in human infertility. Sera, sperm, and seminal plasma were analyzed for antisperm antibodies by the sperm immobilization technique, tray agglutination technique, and immunobead binding technique. Sperm motility and fertilizing capacity were analyzed by sperm motion analysis and sperm penetration assay, respectively. CSF-1 concentration was estimated by the competitive radioimmunoassay. CSF-1 was detected in sera of both fertile and immunoinfertile men (mean +/- SD; fertile men: 52.9 +/- 10.3 pg/mg protein; immunoinfertile: 58.2 +/- 19.5 pg/mg protein; p > .05). CSF-1 was also detected in the seminal plasma of fertile, immunoinfertile, and male factor-infertile men (mean +/- SD; normal fertile men: 1.7 +/- 3.5 ng/mg; immunoinfertile men: 10.9 +/- 15.6 ng/mg; male factor-infertile men: 0.85 +/- 0.25 ng/mg). The levels of CSF-1 were highest in the immunoinfertile men, followed by those in fertile and male factor-infertile men. The average level in immunoinfertile men was significantly different from the average level in fertile or male factor-infertile men (p < .0001). Interestingly, the concentrations of CSF-1 per milliliter of seminal plasma was in general approximately 5 times greater than those in serum. These findings indicate that elevated seminal plasma CSF-1 concentration is correlated with male 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.

Antiidiotypic antibodies to sperm in sera of fertile women that neutralize antisperm antibodies

The presence of antiidiotypic antibodies (ab-2) to sperm was investigated in the sera of fertile, infertile, and virgin women using sperm-specific anti-FA-1 monoclonal antibody Fab'.ab-2 were detected in 71% (17/24) of sera from fertile women and in none (0/12) of the sera from virgin females by the enzyme-linked immunosorbent assay, Western blot procedure, and immunoprecipitation procedure. Sera from infertile women that had antisperm antibodies showed a minimal presence of ab-2, with only three sera (13%, 3/23) demonstrating the presence of low levels of ab-2. The ab-2 present in fertile women were capable of neutralizing the fertilization-inhibitory activity of anti-FA-1 antibody in a concentration-dependent manner in a human sperm penetration assay (SPA) of zona-free hamster oocytes. ab-2 were also capable of inhibiting the binding of antisperm antibodies to the sperm surface as determined by the immunobead binding technique. This is the first report demonstrating the presence of ab-2 in the sera of fertile women that are capable of neutralizing antisperm antibodies present in sera of infertile women. These findings suggest that the inability to detect antisperm antibody activity in the sera of fertile women may be due to higher levels of ab-2 present in these sera than levels found in sera of infertile women, although both groups may be producing antisperm antibody response after sexual exposure to sperm.

Fucoidin binding activity and its localization on human spermatozoa

We previously reported that fucoidin (a polymer of predominantly sulfated L-fucose) significantly inhibits: (1) tight binding of human sperm to human zona pellucida in vitro and (2) stimulation of the acrosome reaction by acid solubilized human zona pellucida. Here, we determined fucoidin binding activity on human spermatozoa and its localization on both live and permeabilized human sperm populations. A typical binding curve was demonstrated with biotinylated fucoidin. In competitive inhibition assays with unlabelled fucoidin or human sperm membrane extracts, IC50's were 4.0 micrograms/ml and 31.4 micrograms/ml, respectively. Fucoidin binding was localized over the acrosomal region of methanol-fixed human sperm and this pattern of binding significantly decreased from 92 +/- 3% to 74 +/- 6% with calcium ionophore A23187 treatment (p < 0.01). Binding of fucoidin-coated beads to live (non-permeabilized) human sperm was less than 1%. Addition of the detergent, Triton-X, to permeabilize sperm membranes resulted in a significant increase in binding (p = 0.001). These results provide evidence for the presence of a fucoidin binding compound in human spermatozoa that is localized to the membranes of the acrosomal region and can be extracted by a mild detergent extraction. Absence of binding by fucoidin to intact but not permeabilized spermatozoa suggests that the heteropolysaccharide binds to a receptor within the acrosomal matrix. However, further investigation is warranted to determine whether a fucoidin binding site is present both at the sperm's surface for the initial contact with the zona pellucida, and also for secondary binding after exposure of the acrosomal membranes.

Effect of early antibiotic treatment on the formation of sperm antibodies in experimentally induced epididymitis

This investigation was conducted to evaluate whether or not experimentally produced epididymitis could induce the development of cytotoxic sperm antibodies and if effective antibiotic therapy could reverse the development of immunity to sperm. Escherichia coli was injected into the tail of the epididymis in adult Lewis rats to induce epididymitis and was allowed to incubate for 24 h, 72 h, 8 days, or 15 days. Serum titers of cytotoxic sperm antibodies at these time intervals were determined. Sperm antibody titers began to rise 3 days after inoculation, peaked, and plateaued at 8 days. The titers were negligible in the control rats. Two other groups of rats were inoculated with E. coli in a similar manner and were treated with tetracycline 25 mg/kg/day starting at either 24 h or 8 days after inoculation, for 7 days. The antibody titers became negligible in these two treated groups, the results being statistically significant when contrasted with the infected but untreated groups (p < .001 and < .05, respectively, for the 24-h and 8-day groups). However, histological examination of the antibiotic-treated and untreated specimens revealed significant inflammation and infection of the epididymis in both treated groups. Testicular alterations were consistent in both groups. It is concluded that epididymitis consequent to infection with E. coli can induce cytotoxic antibody formation in Lewis rats. Treatment with appropriate antibiotics may suppress the antibody response either through a direct immunosuppressive effect of the antibiotic or through a decrease in the antigenic load of killed sperm secondary to eradication of the infection.

Assessment of circulating agglutinating anti-sperm antibodies in buffalo cows with unexplained infertility and an attempt to identify buffalo sperm isoantigens

The presence of circulating agglutinating anti-sperm antibodies as cause for unexplained infertility of artificially inseminated buffalo cows was assessed. An attempt to identify buffalo sperm isoantigens was also made. The following methods were applied for that purpose: the tray agglutination test (TAT), SDS-polyacrylamide gel electrophoresis, and immunoblotting. The results obtained showed that three of 90 sera from buffalo cows with unexplained infertility were positive in TAT (3.3%) and their titers were low. A total of 27 spermatozoal polypeptides reacted positively with the IgG-isoantibodies of one of the sperm agglutinating sera in immunoblotting. Of the control sera 12 also revealed individual variations in the number of positive fractions on the blots. On the basis of comparing the blot with the positive sperm agglutinating serum to the blots of the positive controls, two buffalo sperm isoantigens were identified, with the respective molecular weights of 40 kDa and 120 kDa. In conclusion, circulating agglutinating anti-sperm antibodies are very rarely detected in buffalo cows with unexplained infertility after several artificial inseminations.

Screening assays for immunologic infertility: a comparison study

Because the immunobead antisperm antibody test (IBT) is difficult to learn and results are heavily operator-dependent, we compared findings on IBT with those of SpermMAR and SpermCheck in 58 patients to determine whether the latter two tests could demonstrate improved screening ability. Assays performed on both sperm and serum (i.e., direct and indirect) yielded 100% positive predictive values when IBT was used as the standard. Both SpermCheck and SpermMAR are easier to perform, and, as the former has a slightly greater sensitivity, we recommend SpermCheck for the detection of immunologic infertility.

A comparison of the direct immunobead test and other tests for sperm antibodies detection

The authors report the results of a correlation study between the direct Immunobead Test (d-IBT) and other techniques for antisperm antibodies detection. The Gelatin Agglutination Test (GAT) and Tray Agglutination Test (TAT) were used to detect antibodies in blood serum and seminal plasma ("indirect methods"). The Direct IgG Mixed Antiglobulin Reaction Test (d-MAR test) was used to detect sperm antibodies bound to the sperm surface ("direct method"). A good concordance between the methods, measured by phi and K tests, was found and satisfactory mathematical models were established by regression analyses.

Inhibition of human sperm-zona pellucida tight binding in the presence of antisperm antibody positive polyclonal patient sera

Patient sera previously characterized as containing high levels of IgG and IgA antisperm antibodies that bound to the sperm surface, most specifically the head region, were evaluated for their effect on sperm-zona pellucida tight binding as assessed by the hemizona assay (HZA). Of the ten patient sera tested, 7 reduced zona binding by approximately half. Two of the most strongly inhibitory (greater than 70% inhibition) were examined for their effect on the prefertilization maturation of sperm. The patient sera did not affect sperm motion characteristics, or development of hyperactivated motility. However, in the presence of these sera some impedance was noted in calcium uptake after stimulation with human follicular fluid and in the acrosome reaction after calcium ionophore induction. Whether these two sera specifically affect sperm-zona pellucida binding or non-specifically affect the normal progression of capacitation remains to be eludicated.

A comparison of swim-down and swim-up methods for the extraction of high motility sperm

High quality motile sperm are essential for the success of the in vitro fertilization-embryo transfer program and related procedures, for the performance of sperm antibody assays, and other in vitro tests of sperm function. Two methods for the extraction of high motility sperm, swim-down and swim-up, were compared on 30 ejaculates, and sperm motility was assessed at intervals up to 18 hours. The swim-down method was simpler, shorter, and provided a significantly better recovery of sperm with sustained high motility than did the swim-up method.

Binding of sperm-reactive antibodies in human sera to surface-associated antigens on human sperm compared by indirect immunobead, immunofluorescence, and immunogold assays

Human sera were identified as positive or negative for sperm-reactive antibodies in a solid-phase enzyme-linked immunosorbent assay (ELISA). Of these, 28 positive and 22 negative sera were blind-coded and used as first antibody to compare three immunoassays, a modified liquid-phase indirect immunobead assay (IBA); a liquid-phase indirect immunofluorescence assay (IFA); and a solid-phase indirect immunogold assay (IGA). These three immunoassays perform both as sperm-reactive antibody detection assays and as sperm-associated antigen localization assays. As antibody detection assays, the IBA, IFA, and IGA gave 37, 27, and 28 positives and 13, 23, and 22 negatives, respectively. The usefulness of the IBA as an antigen localization assay was limited by the size of the marker, while the smaller IFA and IGA markers enabled increased resolution of binding patterns of sperm-reactive antibodies to surface-associated sperm antigens. Although the antigen-antibody binding patterns were almost identical for IFA and IGA, suggesting the same sperm-associated antigens were detected by both assays, the IGA reaction product was stable, higher in resolution, and visible by light microscopy.

A comparison of sperm antibody assays

Cytotoxicity and Immunobead-binding immunoglobulin G assays agreed in 81% of sera from infertile men (n = 173), 74% of sera from their wives, 75% of seminal plasma, and 82% of cervical mucous samples (p less than 0.001; chi 2 analysis of positive and negative results) when tested against sperm from the same donors. Cytotoxic and immunofluorescent IgG antibody results agreed in 79% of sera from men and women, 76% of seminal plasma, and 76% of cervical mucus (p less than 0.001; chi 2 analysis of positive and negative results). Titers or percent binding of sperm by cytotoxicity, hemagglutination, and IgG Immunobead-binding or immunofluorescence assays in serum and secretions of husbands and wives correlated (p less than 0.001). A significantly increased number of positive results was observed in cytotoxic and Immunobead-binding IgG assays when the husbands' and donors' sperm were used rather than donors' sperm alone. On the basis of this study we conclude: (1) that cytotoxicity, Immunobead-binding IgG, and immunofluorescent IgG sperm antibody assays correlate when sperm from the same source are used, (2) that women's isoimmunity to husbands' sperm is associated with their husbands' autoimmunity to sperm irrespective of the assay, and (3) that it is desirable to use sperm from the husbands and nonautoimmune fertile men in these assays.

Comparison of the direct radiolabeled antiglobulin assay and the direct immunobead binding test for detection of sperm-associated antibodies

Thirty-seven semen samples were assayed for sperm-associated IgG and IgA using the immunobead test. Portions of these sperm samples were sent for testing with a direct radiolabeled antiglobulin assay and the testing results were compared. If the results of the immunobead test when only tail-tip bead binding was noted are regarded as negative, there was close correlation between the two assay methodologies.

Detection of sperm-bound antibodies in the male partners of infertile couples using the immunobead test

The aim of this investigation was to determine the incidence of sperm-bound antibodies in the male partners of an unselected infertile population using an immunologically specific test (IBT). With this method 34 out of 450 infertile men (7.55%) were positive for one or more of the immunoglobulins IgA, IgG and IgM. For IgG and IgA, the majority of antibody binding was located on the entire sperm with a minor amount bound to the head or tail. For the IgM, the majority of the binding was detected to the tail tip, and tail binding was observed only in a minority of cases.

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.

The detection in human sera of antisperm antibodies reactive with FA-1, an evolutionarily conserved antigen, and with murine spermatozoa

Evolutionarily conserved antigens are present on spermatozoa of several mammalian species. We tested sera from infertile men and women containing antisperm antibodies (ASAs) for their reactivity with FA-1, an antigen known to be present on murine and human spermatozoa. Fifty percent of male sera and 63% of female sera contained anti-FA-1 antibodies, as judged by enzyme linked immunosorbent assay (ELISA). Fourteen percent of male sera and 50% of female sera were also shown to possess ASAs reactive with living mouse spermatozoa, and murine in vitro fertilization was inhibited by human antibodies. These results suggest that the transfer of immunoglobulins from human sera to spermatozoa of other species may provide a model to study how ASAs effect sperm function.

Antibodies to sperm basic nuclear proteins detected in infertile patients by dot-immunobinding assay and by enzyme-linked immunosorbent assay

The auto-antibody response in infertile men was investigated by means of immunoenzymatic methods, dot-immunobinding assay (DIBA), and ELISA, using, as antigens, human sperm basic nuclear proteins. Comparison was made, for the same patients, with antibody response to membrane antigens, detected by tray agglutination test (TAT), spermotoxic test (STT), and immunobead binding test (IBT). A very good agreement was observed between the two kinds of antibody responses. Thus, an ELISA or a dot-immunobinding test with sperm nuclear proteins may be considered as a simple and sensitive method for detection of auto-antibodies in infertile men. The reactivity in ELISA of various synthetic peptides corresponding to sequences of human protamines HP1 and HP2 was also studied: all the sera containing anti-nuclear antibodies do not react with synthetic peptides. This observation suggests that antibodies to sperm nuclear proteins recognize conformational epitopes that are not present on small synthetic peptides.

Sperm antibodies, semen quality, and male infertility

Twelve couples who underwent infertility investigations at the Universitas Hospital in Bloemfontein were examined using several tests: postcoital (PCT), sperm-cervical-mucus-contact (SCMC-T), indirect immunobead (IBT), tray-agglutination (TAT), and sperm-immobilization procedures (SIT). Two factors played a role during the immunologic evaluation of a couple: semen quality and the intensity of the antibody in the cervical mucus or seminal plasma.

Detection of antisperm antibodies on the surface of motile spermatozoa. Comparison of the immunobead binding technique (IBT) and the mixed antiglobulin reaction (MAR)

Investigators testing for antisperm antibodies have recently focused on tests that detect the Ig classes of the sperm-bound antibodies. The aim of this study was to compare the sensitivity of two of these tests, viz. the immunobead binding technique (IBT) and the mixed antiglobulin reaction (MAR). Twenty-one male or female sera were tested for IgG and IgA antisperm antibodies with the IBT and the MAR. The sera were selected on the basis of the IBT results, and the MAR was carried out without knowledge of these results. For IgG antisperm antibodies, there was a highly significant correlation between the two tests (P = 0.0043), whereas, for IgA antisperm antibodies, the correlation was poor (P = 0.2951), because the IBT revealed a positive reaction for IgA in sera in which no such antibodies could be detected by the MAR.

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.

Special antigens on sperm from autoimmune infertile men

Sera from three fertile men and four infertile men without sperm antibodies, 17 infertile men with sperm antibodies in serum and seminal plasma (S.P.), and 25 infertile men with sperm antibodies in S.P. were tested by Western Blot analysis against sperm membrane extracts and S.P. from fertile nonautoimmune men and infertile autoimmune men. Sera from fertile men reacted against common antigens with molecular weights (MW) of 28, 38, 48, 60, and 68 kD present on sperm from autoimmune and nonautoimmune men and special antigen of MW 76 kD on the sperm of fertile men. Sera from 15 of 17 (88%) autoimmune infertile men with sperm antibodies in serum and S.P. detected special antigens with MW of 58 kD (sera reactivity in 47% of these men), 43kD (in 29%), 30 kD (in 24%), 35 kD (in 18%), 52 kD (in 12%), 41 kD (in 6%), and 71 kD (in 6%) on the sperm of autoimmune men in addition to the common antigens. Sera from 15 of 25 (60%) men with sperm antibodies in their S.P. showed reactivity to special antigens with MW 52 kD (in 20%), 35 kD (in 16%), 41 kD (in 16%), 58 kD (in 8%), 70/71 kD (in 8%), 30 kD (in 8%), and 56 kD (in 4%). Sera from 18 of 42 (43%) infertile men with sperm antibodies also detected special antigens of MW 26, 46, and 76 kD present only in fertile men's sperm. Sera from only 15 of 42 (36%) autoimmune infertile men reacted against special antigens with MW 17, 20, 23, 30, 43, and 58 kD in the seminal plasma of autoimmune infertile men.(ABSTRACT TRUNCATED AT 250 WORDS)

Sperm and seminal plasma antibodies in acquired immune deficiency (AIDS) and other associated syndromes

Although HIV has been established as the etiologic agent in AIDS, other contributory cofactors may be responsible for selective clinical manifestations of the syndrome. While the pathogenesis remains unclear, the development of immunologic abnormalities observed in some homosexual males with AIDS and AIDS-related complex may be attributed to repeated exposure to allogeneic sperm and seminal plasma components. Accordingly, antibody levels to semen fractions were measured in sera from 338 individuals (295 AIDS, 36 ARC, 16 randomly selected homosexuals, 29 patients with infectious hepatitis, 12 hemophiliacs, 20 rheumatic disease patients, and 24 healthy heterosexual adults). The methods were (i) passive hemagglutination for antibodies to human seminal plasma (HuSePl), and (ii) indirect immunofluorescence (IF) assay on methanol-fixed human sperm noting staining of acrosomal, equatorial, postnuclear, and tail main-piece regions. HuSePl was positive in 31% AIDS sera, while 39% were positive by IF. ARC sera were 30% positive for HuSePl and 38% positive IF. No control sera were positive. Results reveal a significant incidence of antibody to sperm and seminal plasma components in ARC and AIDS patients. Because of the known immunomodulating properties of both, it is possible that these responses may indicate risk factors for disease progression and severity.

Evaluation of immunobead test (IBT), tray-agglutination test (TAT), and sperm immobilization test (SIT)

The present investigation relates the results obtained by the indirect immunobead test (IBT) to those found during the tray-agglutination test (TAT) and sperm immobilization test (SIT) performed on 16 positive blood sera samples. An IB binding of greater than 50% can be regarded as significantly positive (p less than 0.05), since 77% of the positive IB samples with an IB binding of greater than 50% also revealed a TAT titer of greater than 1:8. The IBT is an excellent test for the detection of sperm antibodies during routine screening procedures.

Antisperm antibodies bind with different patterns to sperm of different men

Immunologic infertility is an important area of current clinical research. The immunobead test is a laboratory method that identifies the classes of antisperm antibodies and their binding sites on the sperm surface. In this study we have investigated the variability in the pattern of antibody binding to spermatozoa after passive transfer from blood serum. Serum from a single donor containing antisperm antibodies of the IgG class was used in all experiments. The spermatozoa from 27 semen donors were found to differ significantly in the degree and location of immunobead binding after exposure to this serum. There was substantial day-to-day variability in the results for individual semen donors and the overall variability in test results was significantly greater when a number of semen donors was used rather than a single donor. These data suggest that details of antisperm antibody binding after passive transfer from body fluids may depend on the sperm donor. The design of research studies involving antibody transfer must take this source of variability into account.

Prevalence of sperm surface antibodies in the male partners of infertile couples as determined by immunobead screening

A single simple laboratory test for the detection of sperm surface antibodies is described. Spermatozoa from 300 men who were investigated for infertility were tested for sperm surface antibodies using the Immunobead test (IBT). IBTs for IgG, IgA, and IgM were performed on each sample as well as an IBT using an Immunobead with activity against both light and heavy immunoglobulin chains and therefore capable of detecting any of the three isotypes ("GAM-IBT"). An excellent correspondence was found between GAM-IBT-positive samples and those positive by one or more of the isotype-specific Immunobeads. In 29 of 32 positive tests, the GAM bead binding was within 5% of the most positive isotype-specific bead's binding. There were no false-positive or false-negative tests comparing the GAM-IBT with the isotype-specific IBTs.

Sperm and seminal plasma antigens from autoimmune men induce immunological infertility

Adult male rabbits were immunized with normal saline (controls), sperm extracts from 2 autoimmune men, seminal plasmas from the same autoimmune men, sperm extract from a fertile nonautoimmune man, and seminal plasma from the same fertile nonautoimmune man. All the sperm donors were free from infections. Rabbits immunized with fertile men's sperm extract and seminal plasma had significantly elevated postimmunization hemagglutinating but not cytotoxic sperm antibodies and reproduced normally. Rabbits immunized with autoimmune men's sperm and seminal plasma antigens developed high titers of cytotoxic and hemagglutinating sperm antibodies in their serum and seminal plasma and their reproduction was markedly reduced. Their sera and seminal plasma reduced motility of sperm from a normal donor. The immune responses were confirmed by electron microscopic immunocytochemistry. This technique revealed membrane-bound endogenous IgG on sperm from only those rabbits immunized with sperm extracts from autoimmune men. These antisera reacted against a protein in the 58,000 D range; antisera to fertile man's sperm extract reacted against three proteins with molecular weights of 15,000, 18,400, 25,000, and 44,000 D, as judged by Western blot. Rabbit antisera to seminal plasma from autoimmune men reacted against several proteins; additionally, it detected two proteins with 43,000 and 68,000 molecular weight detected by antiserum to fertile man's seminal plasma. Sperm and seminal plasma antigens from autoimmune men are different in their elicited immunogenic responses from those of fertile nonautoimmune men. These responses are relevant to infertility.

Autoantibodies against spermatozoal antigens detected by immunoblotting and agglutination. A longitudinal study of vasectomized males

Sera taken pre- and post-operatively at regular intervals within a year from 16 men undergoing vasectomy were analysed for autoantibodies against spermatozoal proteins by immunoblotting. The reaction patterns were compared with the results of sperm agglutination tests. Immunoblotting revealed the presence of autoantibodies against various spermatozoal polypeptides in all sera taken pre-operatively and post-operatively. On average, seven polypeptides showed reaction. During the post-operative period two patients developed spermatozoal agglutinins in moderate titers (greater than 16) but in immunoblotting no change in band reactivity was observed for these two patients. However, scanning of the immunoblotting results revealed that one of the patients, although without sperm agglutinins, during the post-operative period showed an increasing band colouring of a polypeptide of Mr 31,500, reflecting an increased level of the corresponding antibodies.

Motion characteristics of spermatozoa from men with cytotoxic sperm antibodies

Semen samples from 55 fertile nonautoimmune and 44 infertile sperm autoimmune men were evaluated by computerized sperm cell motion analysis. Sperm counts (mean +/- SEM, 59.6 +/- 10.3 X 10(6) per ml), motility (39.0 +/- 4.6%), mean swimming speed (micron/sec, 26.5 +/- 0.9), mean linearity (straight line distance of the cell track divided by the actual track length and multiplied by 10, 6.5 +/- 0.2), and motility index (% motility X mean speed, 10.7 +/- 1.4) in 23 men with significant titers of cytotoxic sperm antibodies in their serum and seminal plasma were less (p less than 0.0001) than those in the fertile controls. However, these parameters were comparable in 18 men with sperm antibodies in their seminal plasma but not in their serum, and the control group. Infertile men with serum cytotoxic sperm antibodies had more sperm cells swimming at 11-30 micron/sec, and fewer moving at 31 micron or higher; this was in contrast to results obtained from fertile men (p less than 0.05). The percentages of sperm cells moving at 21-30 micron/sec were increased, while those moving at 51-60 microns/sec were decreased in men with seminal plasma sperm antibodies, versus controls. Spermatozoa with low linearities (less than or equal to 6) were higher (p less than 0.05) in men with serum and seminal plasma cytotoxic sperm antibodies than in the fertile group.(ABSTRACT TRUNCATED AT 250 WORDS)