Phagocytosis of ejaculated spermatozoa

In patients with accessory gland infections or subjects who have sperm antibodies in their semen, the presence of macrophages with phagocytic activity on ejaculated spermatozoa is significant. Light microscopy cannot certify phagocytosis because it does not give a three-dimensional view of the cells and can lead one to mistake superficial adherence of the spermatozoa to the macrophage for phagocytic activity. For that reason, scanning electron microscopy was used in this study. The samples, fixed with 2.5% glutaraldehyde in phosphate-buffered saline, were processed for observation with light microscopy (Giemsa or Papanicolaou stain) or with scanning electron microscopy (cell selection, critical point drying and paladium-platinum sputtering). With scanning electron microscopy, inactive macrophages had large membrane folds and a globular structure similar to those seen in ascites, whereas when active, they decreased in volume and developed a surface with granules or blebs. Inactive macrophages were rarely seen. A few minutes after mixing the different fractions of the ejaculate, phagocytosis reached such a level of activity that the spermatozoa partly covered the macrophages. Thus, we observed that the spermatozoa were caught by the head first in some instances but by the main-piece fragment of the tail first in other instances; very rarely were they taken by the midportion, between the head and tail. The presence in the ejaculate of macrophages with phagocytic activity on living, motile spermatozoa thus indicates that the encounter between the macrophages and spermatozoa was a result of the assemblage of components that make up the ejaculate. In this way the contributions of the prostatic gland and seminal vesicles play an important part in the spermiophagy of spermatozoa.