Quantitation of sperm bindable IgA and IgG in seminal fluid

Use of specific monoclonal antibodies to secretory IgA for the detection of spermatozoal antibodies in serum and seminal plasma by enzyme-linked immunosorbent assay

The role of anti-sperm secretory IgA has recently received attention since some workers feel it plays an important role in the prognosis of the immunologically infertile couple. Current methods used in our laboratory cannot separately detect anti-sperm secretory IgA. An enzyme-linked immunosorbent assay (ELISA) utilizing specific monoclonal antibodies to secretory IgA was used to detect anti-sperm secretory IgA as well as anti-sperm monomeric IgA and IgG in serum and seminal plasma of a sperm-antibody-positive (ASA+) and sperm-antibody-negative (ASA-) group of men. Results showed significantly raised serum levels in the ASA+ group when compared to the ASA- group for anti-sperm secretory IgA (P less than .001), anti-sperm monomeric IgA (P less than .001), and anti-sperm IgG (P less than .01). Seminal plasma levels were also raised in the ASA+ group, but only significantly so for monomeric IgA (P less than .02). The performed ELISA has definite potential in research, especially with the use of monoclonal antibodies for the detection of anti-sperm secretory IgA, but cannot as yet be used as a prognostic predictor of fertility in the individual antibody-positive patient. Infertility specific antigens will have to be identified and isolated and subsequently used in the ELISA.

Antisperm antibody tests: traditional methods compared to ELISA

Enzyme-linked immunosorbent assays (ELISAs) to detect sperm antibodies can be a useful addition to other tests. ELISAs allow more quantitative and detailed information than some other tests, but results should be compared to those of other tests. This study was conducted to correlate results of an ELISA that used a sperm membrane extract as antigen with those of other tests. Semen, seminal plasma, and serum of 34 sperm-antibody-positive and 36 sperm-antibody-negative men were tested. There was poor correlation between the ELISA results and those of the other tests. Only the results of a direct immunobead test done on semen correlated fairly well with results from ELISAs done on serum. Further studies are needed on fertility-specific antigens that can be identified and isolated and then studied by means of ELISAs.

Comparison of a direct and indirect ELISA for quantitating antisperm antibody in semen

A direct and an indirect quantitative ELISA for antisperm antibody were compared using the spermatozoa and cell-free seminal fluid of 66 infertile males. The normal concentration of sperm binding immunoglobulin was less than or equal to 1.5 fg Ig per spermatozoon for the indirect seminal plasma assay and less than or equal to 1.5 fg Ig per spermatozoon by the direct assay. Of the 66 infertile males, 21% (14/66) had elevated levels of antisperm antibody in their seminal plasma and 26% (17/66) had elevated levels bound directly to their spermatozoa. The direct correlation between the results of these assays was 94%. A simple linear regression analysis between the indirect and direct measurements of antisperm antibody resulted in a correlation coefficient of r = 0.907. There was no statistically significant difference between results from the direct and indirect methods of the patients as a group. However, there was evidence of autospecificity in a small percentage of males who had elevated levels of antisperm antibody by the direct assay that was not detected by the indirect assay using pooled donor spermatozoa.

Antibody binding specificity to donor sperm in sera from infertile patients

Indirect testing for elevated sera levels of antisperm antibody assumes that all relevant antigens are present on the target sperm utilized. In the present study, the heterogeneity of reactivity of positive sera with sperm from different donors was addressed. When 68 sera that previously tested positive by either sperm immobilization test (SIT) or ELISA or both were tested for antisperm antibody levels by a quantitative ELISA using nine different sperm donors, the frequency of positive reactions was 51% for men and 81% for women. A 50% correlation of SIT- and ELISA-positive results could be improved to 85% using the same sperm specimen. This would improve the overall correlation of functional and ELISA test results from 95% to 99% in the infertile population studied. The data suggest that individual sperm may vary in their antigenic expression and that comparison of methods between laboratories could be improved if equivalent target sperm were used.