ABSTRACT: Human spermatozoa may be agglutinated by bacteria, virus, and mycoplasmas, as well as by epithelial cells and cellular debris. Agglutination may also be caused by sperm-agglutinating antibodies, but controversy exists as to its significance. One reason for the controversy is that the degree of agglutination has generally been evaluated in a wet smear. During this routine examination, the specimens are often shaken and a part of the specimen is usually transferred to a microscope slide before examination. Such mechanical agitation may cause the agglutinates to break up. Later, the spermatozoa reagglutinate but these agglutinates are usually smaller and may easily be overlooked and therefore, its significance has not been fully recognized.
In the present study, portions from ejaculates were obtained immediately after ejaculation and kept under liquid parafin oil in microchambers, a technique that permits the agglutination to proceed undisturbed, but still under observation. The degree of agglutination in ejaculates from 129 men with tail-to-tail (T-T) and 36 men with head-to-head (H-H) sperm-agglutinating antibodies were compared with findings in 138 men without antibodies, and the influence of different titers evaluated. The results indicate that ejaculates from men with H-H or low titers (≤ 1:32) of T-T sperm-agglutinating antibodies displayed the same degree of agglutination as was seen in the ejaculates from men without any antibodies. Patients with high T-T titers (≥ 1:512) very often had a quite pronounced or complete agglutination in the ejaculates.
Evaluation of seminal fluid using anion exchange chromatography, gel filtration, and various absorption experiments indicated that the T-T sperm-agglutinating factor in the seminal fluid was caused by IgA antibodies and in a few samples the T-T agglutination was also caused by IgG antibodies. Analysis of the T-T sperm agglutination in male sera demonstrated that this factor was caused by IgG antibodies and that H-H agglutination was caused by IgM antibodies. Head-to-head agglutination was not present in the seminal fluid, which is consistent with the fact that IgM antibodies do not penetrate to the seminal fluid.