Bromelin for liquefaction of cervical mucus in sperm antibody testing: its effect on spermagglutinating immunoglobulin G

Evaluation of human spermatozoa in cervical mucus: comparison of different microscopic and extraction techniques

This study was designed to describe an accurate and consistent microscopic technique for the assessment of sperm number and motility in sperm-cervical mucus samples, such as those of postcoital tests (PCTs), and to identify a suitable method to extract functional spermatozoa from cervical mucus (CM). Sperm-CM preparations containing various sperm concentrations were counted using three different microscopic illuminations. The dark field-Makler technique was compared with the more classical bright field-slide technique currently used by our clinicians. Several sperm extraction techniques were applied first to bovine (BCM) and then to human (HCM) cervical mucus. Dark field microscopic illumination provided accurate, fast, and easy sperm identification. Counting variability was significantly greater with bright field-slide than with dard field-Makler, while sperm motility was always higher with this latter methodology. A high degree of agreement (intraclass correlation coefficient = 0.965) among three raters, i.e., low interobserver variability, was obtained only with dark field-Makler. Extraction procedures based on "swim-out," Percoll, trypsin, an enzyme cocktail, and mercaptoethanol resulted in small sperm yields in BCM. Mercaptoethanol and trypsin also showed poor sperm recovery in HCM. Among the protocols with the largest yields, the mechanical technique had the largest amount of residual CM, and bromelain reduced sperm motility. The extraction with dithiothreitol (DTT) showed the best results with a mean sperm recovery of 76% and enhanced sperm motility. Sperm viability as well as spontaneous and induced acrosome reaction were conserved in all techniques. In conclusion, use of the dark field-Makler counting technique in combination with DTT extraction of spermatozoa from CM samples, such as those of PCTs, would allow accurate and functional assessment of spermatozoa for preliminary contraceptive efficacy or infertility evaluation.

Secretory IgA in cervical mucus

PURPOSE

Sexually active adolescent girls are uniquely vulnerable to sexually transmitted disease, including cervical cancer and AIDS. Little is known about the development of genital immunity in adolescents. Secretory IgA (sIgA) in cervical mucus is an important component of genital immunity. We studied sIgA levels in cervical mucus samples for both adolescent and adult females.

METHODS

Samples were collected in a university-based adolescent medicine clinic and a university student health center. Participants consisted of 13 sexually active adolescent girls and fourteen adult controls. Samples were collected in the course of routine pelvic exams. All subjects were at least two years post menarche. Mucus was aspirated directly from the cervical os. Diluted samples were liquefied with a proteolytic enzyme (bromelain). Secretory IgA levels were measured by radial immunodiffusion using IgA2 from pooled human plasma as a standard.

RESULTS

Secretory IgA levels for the adolescent group (mean 0.157 g/L SD 0.080) were slightly lower than for the adult group mean (0.199 g/L SD 0.130) although not statistically significant.

CONCLUSIONS

Cervical sIgA levels were comparable between sexually active adolescents and adults.

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.

A reverse (antibody capture) enzyme-linked immunosorbent assay for detection of antisperm antibodies in sera and genital tract secretions

A reverse (antibody capture) enzyme-linked immunosorbent assay (ELISA) for detection of antisperm antibodies has been developed. The assay enables detection of immunoglobulin (Ig) M, IgG, IgA, or IgM, IgG, and IgA--antisperm antibodies in serum, cervical mucus, and seminal plasma samples. The reverse ELISA is more specific and sensitive than conventional ELISA in detecting human antisperm antibodies of different isotypes. Using this assay, statistically significant differences in levels of antibodies between infertile and fertile individuals were demonstrated in sera and in genital tract secretions. Studies with 143 infertile couples revealed that the presence of antibodies in sera was not necessarily reflected in individual's genital tract secretion and vice versa. These data emphasize the importance of detecting antisperm antibodies in sera as well as in genital tract secretions for correct evaluation of sperm immunity.

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.

Techniques for sperm immobilization test

Several semiquantitative, quantitative, and microassay techniques had been developed to detect antibodies bound to human spermatozoa: sperm agglutination test (SAT), sperm immobilization test (SIT), immunofluorescence test, radioantiglobulin test, enzyme-linked immunosorbent assay (ELISA), mixed erythrocyte-spermatozoa antiglobulin reaction (MAR), "Panning" test, and immunobead test (IBT). Clinical application of these techniques include (a) detection of sperm immobilizing antibodies in sera of sterile women, (b) follow-up study of sperm immobilizing antibodies, and (c) detection of sperm immobilizing antibodies in cervical mucus and other secretions. The chemical structure of antigen epitope corresponding to Mab H6-3C4 may recognize the internally located repetitive unbranched N-acetyllactosamine structure, regardless of terminal substitution at Gal (i.e., sialyl-i as well as i structure). The majority of sperm-immobilization (SI) positive women's sera were absorbed with carbohydrate components on ejaculated sperm, but only one serum competed with Mab H6-3C4 on binding to sperm except a serum from whom lymphocytes were donated to make Mab H6-3C4. The SI agglutinating antibodies (Abs) in women's sera were raised to the carbohydrate epitopes of glycoprotein in HSP, but epitopes might have several different conformational structures. Studies are in progress to find whether or not SI-Abs could be generated to peptide epitope of human seminal plasma (HSP) or sperm.

Results of in vitro fertilization in women with antisperm antibodies in serum, cervical mucus, and follicular fluid

This study was undertaken to investigate the presence of antisperm antibodies (ASA) in serum, cervical mucus, and follicular fluid (FF) of women undergoing in vitro fertilization and embryo transfer (IVF-ET). IgG and IgA ASA directed mostly against sperm head were found at similar concentrations in serum, cervical mucus, and FF of 2 of 34 patients. Ninety-one percent fertilization and 100% cleavage rates, respectively, were observed in one of the two patients. No fertilization occurred in the second patient. In both women, in vitro sperm penetration tests revealed hostile mucus and repeated postcoital tests were poor. It is concluded that the sperm-cervical mucus penetration test and mucus ASA measurements are useful in establishing the diagnosis of immunological infertility.

Detection of antispermatozoal antibodies of IgA class in cervical mucus

A simple procedure for detection of antisperm antibodies of IgA class in human cervical mucus is described and the results of its application to samples from 102 patients are presented. The results suggest that the IgA immunobead test (IgA-IBT) is a specific and clinically useful test for sperm antibodies. There was a strong correlation between the IgA-IBT and the presence of complement-dependent sperm immobilization in serum (Spearman's, r = 0.92, p less than 0.001). Positive IgA-IBT results occurred only in mucus samples that showed poor penetration by normal sperm. An added advantage of the IgA-IBT is that both the immunoglobulin class and the site of binding to the sperm surface can be determined simultaneously.

Immunoglobulin class of sperm antibodies in cervical mucus from infertile women

By immunoaffinity chromatography using anti-IgG, anti-IgM, and anti-IgA coupled to CNBr-activated sepharose 4B, the immunoglobulin class of sperm-agglutinating antibodies was investigated in cervical mucus from four infertile women. In all patients, it was found that the sperm antibodies in cervical mucus belonged to the IgA class, whereas in serum, which was studied in two of the patients, IgG sperm antibodies were demonstrated. Absorption of the four cervical mucus samples with anti-secretory component sepharose 4B revealed that the IgA antibodies in at least two of the samples were SC-IgA antibodies. Investigation of a third sample by sucrose gradient ultracentrifugation revealed that the IgA sperm antibodies were characterized by a sedimentation coefficient between 9S and 13S, strongly suggesting the presence of SC-IgA antibodies. Accordingly, the sperm-agglutinating antibodies were SC-IgA antibodies in at least three of the four samples studied.

Hormonal patterns in infertile women with a deficient postcoital test

Twenty-two women in whom a routine infertility workup had shown no abnormality except for repeated deficient results in the postcoital test (PCT), the patterns of luteinizing hormone (LH), follicle-stimulating hormone (FSH), prolactin (PRL), 17 beta-estradiol (E2), and progesterone (P) were examined during the follicular and periovulatory phases of the menstrual cycle. Cervical mucus (CM) characteristics were also investigated during the pre- and periovulatory phases and scored using a CM score and a sperm penetration meter (SPM) score. The results were compared with those of a control group of seven women with proven fertility. No differences were found between the CM scores of both groups, whereas the SPM score was lower (P less than 0.1) in the infertile group. The preovulatory serum levels of E2 were lower (P less than 0.1) in the infertile group, while the serum levels of PRL (P less than 0.1) and FSH (P less than 0.1) were constantly higher in this group. The mean serum levels of LH and P were almost equal in the two groups. It is concluded that a deficient result in the PCT can be indicative of deviated hormonal patterns in an infertile woman even when the routine fertility investigation is suggestive of a normal ovulatory cycle.

Application of a sperm micro-immobilization test to cervical mucus in the investigation of immunologic infertility

A complement-dependent sperm micro-immobilization test for antisperm antibodies in cervical mucus was evaluated in 195 infertile women. Positive tests were obtained among 17% of women with "unexplained" and 12% with an "organic" basis for their infertility. The results confirmed previous reports of the presence of cervical mucus antibodies in the absence of corresponding activity in serum. Non-complement-dependent sperm-immobilizing activity was also detected in the cervical mucus of several patients. During a follow-up period of 9 to 24 months, 10% of those with "unexplained" infertility who had complement-dependent sperm-immobilizing antibodies in their mucus became pregnant, compared with 29% of those without antibodies. The corresponding pregnancy rates for patients with "'organic" infertility were 18% and 11%. In four patients with positive tests who subsequently conceived, further tests failed to detect the persistence of the immobilizing activity.

Spermagglutinating antibodies and sperm penetration of cervical mucus from infertile women with spermagglutinating antibodies in serum

Spermagglutinins were demonstrated by the tray agglutination technique in cervical mucus collected during presumably-ovulatory cycles in 8 women among 21 patients with spermagglutinating antibodies in serum treated for infertility. A "poor" sperm penetration test was recorded exclusively in women with spermagglutinins in cervical mucus, and the results of the sperm-cervical mucus contact test were significantly correlated to the spermagglutinin titers in cervical mucus. The incidence of spermagglutinating antibodies in cervical mucus from infertile women was estimated to be 2.2% on the basis of the results in the present study. However, an inhibiting effect on sperm penetration in cervical mucus by spermagglutinins is expected to occur in less than 1% of women from infertile couples. A decrease in spermagglutinin titers in cervical mucus observed during estrogen medication was significantly associated with improved sperm penetration in vitro. The latter results may indicate a new approach to the treatment of infertility due to the presence of spermagglutinating antibodies in cervical mucus.

Studies on local immunity to sperm-dissolving of cervical mucus by use of bromelin with retention of antibody activity

The complete dissolving of human cervical mucus was achieved with bromelin. The adequacy and the mildness of this procedure were studied by making both solutions and simple extracts of a number of mucus samples. Both types of preparation were tested for sperm antibody by our methods of agglutination and immobilization. The comparisons showed a high degree of concurrence between these two types, with the bromelin solutions showing positive results more often than the extracts. Other control tests showed that addition of bromelin did not perturb the antibody testing of positive and negative sera. We concluded that addition of bromelin, in a 1/3 volume, gives a quick, thorough and undamaged solution of cervical mucus, on which sperm antibody tests can be done with ease and reliability.