Phagocytosis Of Spermatozoa Research Articles

Ultrastructure of the reproductive system of the black swamp snake (Seminatrix pygaea). IV. Occurrence of an ampulla ductus deferentis.

The distal end of the ductus deferens of Seminatrix pygaea (Cope) differs from more proximal portions of the tube by possessing a highly fluctuated epithelium. Similar morphology has been reported in this area in one lizard and some mammals and the region has been designated in these taxa as the ampulla ductus deferentis. In this study, light and transmission electron microscopy were used to study the posterior ductus deferens in S. pygaea and compare the histology in this region to more proximal regions of the duct and to descriptions of the ampulla of other species. Seminatrix pygaea stores sperm throughout the ductus deferens during the entire year. The epithelium of the ductus deferens is not secretory, but the presence of numerous small apical vesicles indicates a role in fluid absorption. In addition to the highly folded epithelium, clusters of sperm nuclei are more intimately associated with the apical ampullary epithelium than elsewhere in the ductus deferens. No evidence of phagocytosis of sperm was found. In contrast, the ampulla of mammals and presumably the lizard Calotes versicolor is glandular and phagocytic. The common character shared by the squamates and mammals with specializations in this area is the folded epithelium, and whether this is due to shared ancestry with amniotes or is homoplastic is unresolved.

Neutrophil recruitment and phagocytosis of boar spermatozoa after artificial insemination of sows, and the effects of inseminate volume, sperm dose and specific additives in the extender

In this study the recruitment of leucocytes and phagocytosis of spermatozoa after artificial insemination of multiparous sows was investigated. In Expt 1, groups of sows received either no inseminate (n = 6) or inseminates with various concentrations of spermatozoa and seminal plasma or different inseminate volumes (n = 9 per group). In Expt 2, groups of sows received inseminates containing no addition, caffeine + CaCl(2), or excess EDTA (n = 6 per group). Leucocytes and spermatozoa were counted in the collected backflow from the vulva, and in the PBS flushings of the genital tract of sows killed at 4 h after insemination. Tissue homogenates were checked for remaining spermatozoa. Leucocyte recruitment did not depend on the presence of seminal plasma or spermatozoa. In the control groups about 43% of the inseminated spermatozoa were found in the backflow and 5% in the genital tract. Many spermatozoa could be recognized inside polymorphonuclear leucocytes. With an inseminate volume of 20 ml instead of 80 ml, fewer spermatozoa were found in the backflow and more (non-phagocytosed) spermatozoa were recovered in the uterus (P < or = 0.05). With a sperm dose of 0.24 x 10(9) instead of 2.4 x 10(9), a higher percentage of the inseminated spermatozoa was recovered in the oviducts (P < or = 0.05). The use of caffeine + CaCl(2) resulted in lower recruitment of leucocytes (P < or = 0.05) and a higher number of non-phagocytosed spermatozoa in the uterus (P < or = 0.01) compared with controls. The numbers of spermatozoa in the oviducts were not different. Insemination with excess EDTA had no positive effects on the number of spermatozoa in the genital tract.

Ubiquinating Defective Sperm

Sutovsky et al. may have identified one mechanisms for quality control of spermatogenesis. They show that abnormal mammalian sperm are ubiquitinated on their surfaces as they pass through the epididymis. Ubiquitination of these defective sperm appears to represent a tag for their phagocytosis by the epididymal epithelial cells (EECs). The ubiquitination and phagocytosis of sperm by EECs was reconstituted in vitro using a primary EEC culture. The damaged sperm present in the cultures became ubiquitinated and could be identified in intracellular structures in the EECs. The EECs also bound and phagocytosed ubiquitin-coated magnetic beads, confirming that ubiquitin represents a tag for phagocytosis. Thus, extracellular ubiquitination of defective sperm may be one mechanism for quality control during spermatogenesis. A question that remains unanswered is how the EECs know which sperm are abnormal. P. Sutovsky, R. Moreno, J. Ramalho-Santos, T. Dominko, W. E. Thompson, G. Schatten, A putative, ubiquitin-dependent mechanism for the recognition and elimination of defective spermatozoa in the mammalian epididymus. J. Cell Sci. 114 , 1665-1675 (2001). [Online Journal]

Pertubation with Lignocaine – a Possible New Treatment for Women with Endometriosis and Impaired Fertility

The causal relationship between reduced fertility and early stage endometriosis without pelvic adhesions is unclear. Peritoneal fluid from patients with endometrial peritoneal implants contains more leukocytes with an increased capacity to phagocytose spermatozoa. Peritoneal fluid supplemented with lignocaine has a reduced sperm phagocytosis capacity. The present clinical study with low-dose lignocaine pertubation sought to evaluate any clinical effect on fertility. An overall pregnancy rate of 30% was noted in contrast to the natural pregnancy rate for women with endometriosis which is <5%. To confirm these findings a larger study and further dose-ranging are in progress. Up to now the most effective way of increasing fertility for women with endometriosis or unexplained infertility is in vitro fertilisation (IVF). The pertubation treatment with lignocaine is inexpensive and less invasive. Its mechanism is thought to be reduced phagocytosis of the spermatozoa. Another explanation could be a regressive effect directly on the endometriotic implants, taking into account the reduced menstrual pain and increased pregnancy rate after all treatments have been completed. The finding may provide a minimal invasive and more cost-effective alternative to current treatments.

In vitro phagocytosis of boar spermatozoa by neutrophils from peripheral blood of sows

A considerable number of spermatozoa are used in each sow in routine artificial insemination. However, within a few hours after insemination, many spermatozoa are phagocytosed by polymorphonuclear leucocytes. Some aspects of sperm transport in the female genital tract in the sow have been thoroughly investigated, whereas little is known about the mechanisms involved in the phagocytosis of spermatozoa, or about which spermatozoa (fresh, capacitated or dead) are the most susceptible to ingestion by polymorphonuclear leucocytes. In this study, phagocytosis was investigated by use of an in vitro phagocytosis assay. Polymorphonuclear leucocytes were challenged with either untreated, cold-shocked or frozen-thawed spermatozoa, or with spermatozoa that had been treated to induce capacitation in vitro. The influence of serum on phagocytosis was also investigated. Treatment of the semen to induce capacitation in vitro considerably reduced the phagocytosis of spermatozoa, whereas crude treatments like cold-shock or freezing and thawing reduced phagocytosis only in the first 15-30 min of incubation with polymorphonuclear leucocytes. Viable spermatozoa were phagocytosed mainly through a pathway that was independent of complement or other serum components (for example, antibodies). Complement had little effect on phagocytosis of spermatozoa, but did cause acrosomal exocytosis and cell death.

Semen parameters and electron microscope observations of spermatozoa of the red wolf, Canis rufus

Semen parameters were evaluated on ejaculates of a captive population of red wolves (Canis rufus) sampled over two consecutive mating seasons. A total of 31 samples from 15 animals yielded mean sperm motility of 69.6 +/- 19.4%, mean sperm density of 131 +/- 124 x 10(6) ml-1, mean total number of spermatozoa of 470 +/- 465 x 10(6) and mean percentage morphologically abnormal spermatozoa of 35 +/- 11.8%. Restricting the data to animals sampled three times or more or limiting the samples to proven breeders resulted in statistically non-significant differences in these numbers (P < 0.05). When compared with data from other canines the seminal parameters of red wolves are at the lower extremes of the range. In particular the proportion of morphologically abnormal spermatozoa (35%) is approximately twice that seen in other canine species. Light microscopic analysis of abnormal forms revealed that almost half (45%) were bent defects, another 40% were secondary defects (coiled, detached and immature) and 15% were primary defects. Electron microscopy confirmed the presence of substantial numbers of morphologically abnormal forms including double-headed and double-flagellar cells, bent or kinked forms especially in the neck region, acrosomal abnormalities and bizarre spermatids. Approximately one-third of the samples also showed the presence of white blood cells, in some cases demonstrating sperm phagocytosis (spermophagy). These results are consistent with the concept of declining sperm parameters associated with restricted gene pools in numerically limited populations. However, alternative explanations are also explored.

The effect of lignocaine on sperm phagocytosis in the peritoneal fluid from women with or without endometriosis.

The study was undertaken to investigate a possible mechanism for reducing the phagocytosis of spermatozoa by leukocytes in the peritoneal fluid from women suffering from endometriosis. Peritoneal fluids were collected during laparoscopy from women undergoing laparoscopic sterilization or from women under investigation for cause of infertility where the laparoscopic findings were endometriosis. Prepared spermatozoa from one healthy man were incubated in vitro with peritoneal fluid with or without lignocaine. Samples from the incubations were studied daily and the number of viable and dead spermatozoa were counted. The number of free spermatozoa, not adhered to leukocytes, was significantly increased when incubated in human peritoneal fluid supplemented with lignocaine. Thus lignocaine contributes to increasing the number of free spermatozoa and maintaining the possibility of fertilizing an oocyte. For patients with endometriosis, treatment with lignocaine might be a means of increasing the chances of conception. A clinical study is in progress to evaluate this effect in vivo and to search for alternative methods of assisting the fertilization process.

Immunological factors in endometriosis-associated reproductive failure: studies in fertile and infertile women with and without endometriosis.

Immunopathophysiological mechanisms in endometriosis-associated reproductive failure were studied in appropriate populations: infertile and fertile women with and without endometriosis. The incidence of sera positive for any of the autoantibodies tested among infertile women with endometriosis (n = 25) was similar to that observed in the three control groups [unexplained infertility patients (n = 25) and fertile women with (n = 10) and without (n = 25) endometriosis]. The mean volume of peritoneal fluid was significantly elevated in women with endometriosis (both fertile and infertile) as compared with patients without endometriosis (fertile or infertile). The concentration of peritoneal fluid leukocytes and the percentage of cells positive for macrophage markers were significantly increased and the percentage of T lymphocytes significantly decreased in infertile women with endometriosis but not in patients with unexplained infertility and fertile women with endometriosis, as compared with fertile controls without endometriosis. Macrophages from infertile patients with endometriosis had higher sperm phagocytosis than did those from infertile women without endometriosis or fertile subjects with or without endometriosis. Incidences of serum and peritoneal fluid samples embryotoxic to the in-vitro development of 2-cell mouse embryos were significantly higher in infertile patients with endometriosis than in unexplained infertility patients and fertile women with or without endometriosis. It is concluded that immunological mechanisms of endometriosis-associated infertility exist but that these peritoneal immunological factors in infertile women with endometriosis are related to their subfertility rather than to the presence of ectopic endometrial implants. This is supported by the lack of immunological abnormalities observed among fertile women with endometriosis. These immunological abnormalities are lacking in patients with unexplained infertility.

Ultrastructure of the non-germinal cells in the testes of ascidians (Urochordata) and their role in the phagocytosis of sperm

In three species of the Enterogona (Clavelina lepadiformis, Ciona intestinalis and Ascidiella aspersa) and three species of the Pleurogona (Dendrodoa grossularia, Styela clava and Molgula manhattensis) the testis was found to be invested by an epithelium separating the germ cells from the surrounding connective tissue or haemal sinuses. Each epithelial cell probably bears a single cilium, which in C. lepadiformis has a rootlet. Cilia are absent in S. clava. Lipid droplets are common and glycogen-rosettes occur in C. lepadiformis and D. grossularia. The basal plasmalemma varies from smooth to very irregular and in A. aspersa is anchored with hemidesmosomes. Except in S. clava, desmosome-like junctions occur between adjacent cells. Elimination of waste sperm following the reproductive season was observed to be undertaken by the epithelial wall cells in all species except C. lepadiformis. In C. intestinalis, D. grossularia, S. clava and M. manhattensis many of these cells detach and migrate to the interior of the testis where they continue and complete the phagocytosis of sperm. In C. lepadiformis, the non-germinal epithelium plays no role in the elimination of superfluous sperm which is probably phagocytosed, together with the rest of the body, by wandering trophocytes. Within the Urochordata the effectiveness of the testis epithelium as a blood-testis barrier varies, but is not correlated to modes of reproduction as postulated for other taxa.

In Uteroand Lactational Exposure of the Male Holtzman Rat to 2,3,7,8-Tetrachlorodibenzo-p-dioxin: Decreased Epididymal and Ejaculated Sperm Numbers without Alterations in Sperm Transit Rate

Decreased daily sperm production (DSP) and cauda epididymal sperm number (CESN) are some of the most sensitive effects ofin uteroand lactational 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) exposure. The reduction in CESN cannot be fully accounted for by decreased spermatogenesis. To explain the decrease in CESN it was hypothesized that TCDD exposure increases the rate of sperm transit through the excurrent duct system, thereby decreasing the number of sperm in the system at any given time. Pregnant Holtzman rats were administered a single dose of TCDD (1.0 μg/kg, po) or vehicle on gestation day 15 and offspring were weaned on postnatal day (PND) 21. On PND 50, testicular sperm were labeled in five males per litter, from 30 control and 26 TCDD-exposed litters, by injecting 15 μCi [3H]thymidine into each testis, under general anesthesia. Sperm movement through the excurrent duct system was monitored daily 35–64 days post [3H]thymidine injection. On PNDs 92–93, TCDD exposure significantly decreased DSP/testis, corpus and cauda epididymis sperm numbers, vas deferens sperm number, and ejaculated sperm number by 28, 30, 36, 39, and 46%, respectively. The decreases in sperm number in the distal excurrent duct system were greater than the decrease in DSP, consistent with the hypothesis that TCDD exposure causes an effect other than decreased DSP that reduced epididymal and ejaculated sperm numbers. However,in uteroand lactational TCDD exposure did not alter radiolabeled sperm transit time through the whole epididymis (15 days). With TCDD exposure causing no obvious alteration in sperm transit rate, a plausible explanation for the sperm loss is an increase in sperm phagocytosis in the excurrent duct system.

Recombinant soluble human complement receptor type 1 inhibits antisperm antibody- and neutrophil-mediated injury to human sperm.

The pathogenesis of antisperm antibody (ASA)-mediated infertility is postulated to be related in part to complement (C)-dependent sperm dysfunction in the female genital tract. We have previously demonstrated that C can be involved in ASA-mediated sperm injury by the deposition of activated C3 fragments and the assembly of terminal membrane attack complex (C5b-9) leading to C3-mediated sperm binding to neutrophils or C5b-9-mediated sperm motility loss. This study evaluated the protective effect of recombinant soluble C receptor type 1 (sCR1) on ASA-and C-mediated neutrophil/sperm interaction, neutrophil aggregation, and sperm motility loss. Motile sperm with or without neutrophils were incubated in the presence of 10% C-fixing ASA+ serum or ASA- control sera in the presence or absence of sCR1. After defined incubation periods, the following neutrophil and sperm parameters were evaluated: 1) neutrophil aggregation (by the flow cytometric pulse processing method), 2) sperm phagocytosis (by light microscopy), 3) the deposition of C3 cleavage fragments (C3b, iC3b, and C3d) on motile sperm (by immunofluorescence flow cytometry), and 4) the relation between sperm motility loss and sperm-bound C3d. Only the coincubation of neutrophils with sperm in the presence of C-fixing ASA+ sera resulted in marked neutrophil aggregation (20.5 +/- 0.26% vs. 2.4% +/- 1.6; p < 0.0001) and a concomitant increase in neutrophils containing ingested sperm (71 +/- 5.8% vs. 3.5%; p < 0.0001). Soluble CR1 inhibited ASA- and C-mediated neutrophil aggregation by 46% and sperm phagocytosis by 57%. Motile sperm incubated with C-fixing ASA- sera showed a time-dependent increase in the binding of C3 fragments as detected by flow cytometry using anti-iC3b neoantigen, anti-C3c, and anti-C3d monoclonal antibodies (mAbs). A negative correlation (r2 = -0.930; p < 0.001) was found between the increase in sperm-associated C3d fluorescence and the percentage motile sperm in the presence of ASA- sera. Soluble CR1 (200 micrograms/ml) maximally inhibited the binding of anti-C3b, anti-C3c, and anti-C3d mAbs to sperm by 96%, 83%, and 72%, respectively. Thus, sCR1 abrogated the binding of C3 fragments to human sperm and fully protected sperm from C5b-9-mediated sperm immobilization. These findings suggested the therapeutic potential of sCR1 as an intravaginal pharmacophore to prevent C-dependent sperm dysfunction and related inflammatory events in the female genital tract.

Beta 2-integrin (CD11b/CD18) is the primary adhesive glycoprotein complex involved in neutrophil-mediated immune injury to human sperm.

The pathogenesis of antisperm antibody (ASA)-mediated infertility is postulated to be related in part to complement (C)-dependent neutrophil-mediated injury to sperm in the female genital tract. We have reported that sperm-bound IgG activated human C and deposited C3 fragments on motile sperm. We also demonstrated that IgG and C3-bound motile sperm adhered to human neutrophils in vitro, and that this adhesion potentiated the localized release of oxygen radicals at the site of neutrophil/sperm membrane contact. The goal of the present study was to identify the neutrophil surface receptor(s) involved in neutrophil/sperm adhesion and to evaluate their relevance to the pathogenesis of neutrophil-mediated immune injury to sperm. Neutrophils were coincubated with motile sperm in the presence of C-fixing ASA+ sera or control sera. After defined incubation periods, the following neutrophil variables were evaluated: 1) surface expression of Fc (Fc gamma RII and Fc gamma RIII) and C receptors (CR1[CD35], CR3 [CD11b/CD18], and CR4 [CD11c/CD18]) by flow cytometry, 2) neutrophil aggregation by flow cytometry, 3) tyrosine phosphorylation of neutrophil proteins by flow cytometry, and 4) the immune adherence and ingestion of sperm by light and scanning electron microscopy (SEM). The functionality of adhesion receptors was studied by use of a panel of anti-leukocyte monoclonal antibodies (mAbs) for their ability to block neutrophil/sperm adhesion and neutrophil aggregation. Only the incubation of neutrophils and sperm in the presence of C-fixing ASA+ sera resulted in marked (> 70%) sperm binding to neutrophils. Consistent with this pattern, a significant (p < 0.0001) increase in surface expression of neutrophil CD11b and neutrophil aggregation was evident. According to SEM, most of the sperm were linked to the neutrophil by the acrosomal region of sperm head. Maximum expression of CD11b antigen was obtained when neutrophils were coincubated with sperm in the presence of C-fixing ASA+ sera. CD11b up-regulation correlated with a significant (p < 0.05) increase in tyrosine phosphorylation of neutrophil proteins during sperm phagocytosis. Only the combination of mAbs directed to the beta 2-integrin, CD11b (D12/SHCL-3), or CD18 (MHM23) subunits maximally inhibited ASA- and C-mediated sperm adhesion to neutrophils (by 70%) or sperm phagocytosis (by 75%), as well as neutrophil aggregation (by 96%). These findings strongly implicate the CD11b/CD18 glycoprotein complex (CR3) in the adhesive events involved in ASA- and C-mediated immune destruction of motile sperm by neutrophils.

Sperm Immobilizing Activity of a Synthetic Bioactive Peptide 20–44 of 37‐kDa Cationic Antimicrobial Protein (CAP37) of Human Neutrophils

We have previously reported that human sperm coincubated with human peripheral blood neutrophils in the presence of complement (C)-fixing antisperm antibody (ASA)-positive sera are rapidly internalized and degraded within the neutrophil phagolysosome. However, the mechanism by which motile sperm are processed within the phagolysosome is unknown. Various spermicidal/antimicrobial proteins contained in azurophilic granules that can be secreted into the phagolysosome may play a role in sperm disposal. In this study, we examined the expression of a 37-kDa cationic antimicrobial protein (CAP37) during sperm phagocytosis and the effect of its synthetic bioactive fragment, Peptide 20-44 (P20-44), on sperm motility, acrosomal integrity, and mitochondrial functionality. CAP37 expression by neutrophils undergoing ASA- and C-dependent sperm phagocytosis was increased as measured by flow cytometry. Exposure of motile sperm to a cationic P20-44, the bioactive antimicrobial fragment of CAP37, resulted in the loss of sperm motility without disruption of the acrosomal membrane. The sperm immobilizing activity (SIA) of P20-44 was modulated by the length of incubation, the concentration of the peptide, and the pH of the assay medium. SIA induced by P20-44 was partially reversible and was unaffected by the presence of anionic heparin or seminal plasma. Similar to the antimicrobial activity of P20-44, the SIA was also dependent on the presence of a disulfide bond between cysteine residues at positions 26 and 42 and was inhibited by Lipid A. However, the mechanism of action of P20-44 on sperm is not totally dependent on the molecule's cationicity, because five other cationic antimicrobial peptides had no detectable effect on sperm viability. Thus, the mechanism of action of P20-44 on human sperm is different from its cationic antibactericidal effect. These findings established that motile human sperm are sensitive to CAP37 or its synthetic bioactive peptide and suggested that this protein could play a role in neutrophil-mediated immune destruction of sperm in the female genital tract. P20-44 of CAP37 may be useful in investigating the regulation of human sperm motility and to construct "hybrid peptides" with enhanced potency as a component of vaginal contraceptive that could doubly be effective by killing infectious agents and inhibiting sperm transport.

Effects of ischaemia on the caput epididymis and its relationship to higher epididymal obstruction: a qualitative study in the ram

The objective of this study was to determine if localized ischaemia of the caput epididymis in the ram causes morphological changes similar to those characteristic of higher epididymal obstruction in humans. This was tested by performing unilateral occlusion of the superior epididymal artery in 10 rams. At the end of 4 (n = 5) or 28 weeks (n = 4), rams were castrated and the testes and epididymides were weighed. Analysis of histological sections at the light microscope level provided quantitative data on lumen diameter and epithelial cell height of the efferent ducts. Qualitative analysis and specific histochemical stains for identification of lipofuscin pigment provided further information on tissue changes. Electron microscopy was performed on the efferent ducts to assess ultrastructural changes. The results revealed that localized ischaemia of the proximal epididymis caused a dramatic change in tubule calibre of the efferent ducts and initial segment resulting in obstruction of the distal lumina. These changes were more severe following 28 weeks of arterial occlusion. The epithelial cells of the proximal region showed an increase in the number of lysosomes and they became active in phagocytosis of spermatozoa. Lipofuscin pigment accumulated within the epithelial cells and also in macrophage-like cells that had invaded the lumina, interstitium and intra-epithelial regions of the ducts. On the basis of these observations we conclude that the tissue changes which occur in the ram epididymis as a result of localized ischaemia show a striking similarity to those seen in men exhibiting higher epididymal obstruction. This suggests the possible implication of vascular disorders in the aetiology of obstructive azoospermia in men.

Spermatophagy in the Stallion Epididymis: A Scanning and Transmission Electron Microscopy Study

The occurrence of phagocytosis of spermatozoa in the epididymis is a controversial issue in male reproductive biology. In this paper we documented, by scanning and electron microscopy, the presence of spermatophages in the lumen of the proximal region of stallion epididymis. Sperm phagocytosis involving the principal cells that line the cauda epididymidis region was also observed. The possible meaning of this process in the removal of damaged, aged or surplus spermatozoa is discussed. These observations were made in samples obtained from random cases, during the course of research work carried out on the stallion male seminal duct system.

Sexual reproduction in the compound ascidian Diplosoma listerianum (Tunicata). I. Metamorphosis, storage and phagocytosis of sperm in female duct

In the colonial ascidian Diplosoma listerianum (collected in the Lagoon of Venice in 1986 and 1991), ovulating eggs detach themselves from the ovary wall and segregate in the tunic without exposure to seawater. With the aim of finding evidence of the pathway followed by spermatozoa to approach the oocyte, histological and ultrastructural observations were made. The results showed that the hollow ovary elongates in a “fertilization canal” which flanks the sperm duct and opens externally, next to the anus. Intercellular extended tight junctions isolate the lumen of this canal from the blood. Sperm were found in the fertilization canal, both free and in intracellular vacuoles of wandering cells (phagocytes). These sperm showed differences in comparison to those from the sperm duct, which are possible signs of a sperm reaction. The main modifications were shown by the “dense groove”, a narrow invagination of the plasmalemma bound to the nuclear envelope by dense material. In non-modified sperm, the groove runs spirally all along the head, while in those in the fertilization canal, it coils in the anterior half of the head, pressing back the long mitochondrion and endoplasmic tubules. These modifications were interpreted to be result of the release of the dense groove, considered to be a sort of stretched, contractile spring. The presence of sperm in the fertilization canal and particularly in phagocytes is discussed in relation to the capacity for exogenous sperm storage by zooids and to the necessity of waste clearance in order for successive waves of fresh sperm to be able to move towards fully grown oocytes. The origin of the female fertilization canal, the role of its tight junctions, and the complex sperm morphology are discussed as adaptations to internal fertilization in D. listerianum.

Phagocytosis of immunoglobulin G and C3-bound human sperm by human polymorphonuclear leukocytes is not associated with the release of oxidative radicals.

Antisperm antibody (ASA)- and complement (C)-mediated immune injury to human sperm is thought to be caused in part by phagocytic neutrophils. To investigate this process, we co-cultured purified human polymorphonuclear leukocytes (PMN) with swim-up sperm in the presence of ASA-positive and ASA-negative sera and assayed for PMN respiratory burst activity, monitored by the release of superoxide anion (O2-) and hydrogen peroxide (H2O2). Phorbol myristate acetate (PMA) and opsonized zymosan were used as positive controls. Phagocytosis of ASA-positive and C-bound sperm by PMN did not enhance O2- production when compared to incubation of sperm with ASA-negative sera. Phagocytosis of ASA-positive and C-bound sperm also resulted in minimal release of H2O2 when compared with ASA-positive and C-negative sperm that were not phagocytosed. In contrast, PMN were maximally stimulated to release O2- in response to either opsonized zymosan or PMA. The kinetics of PMA-induced O2- release was unaffected by the presence of ASA-positive and C-bound sperm. Cytocentrifuge preparations of PMN incubated with ASA-positive and C-bound sperm revealed limited O2- release at the site of PMN/sperm contact. These results indicated that 1) phagocytosis of motile sperm by PMN requires the binding of both ASA and C to the sperm surface; 2) phagocytosis of ASA-positive and C-positive sperm by PMN fails to release reactive oxygen species; and 3) metabolic processes associated with PMN respiratory burst activity may not be coupled to the ingestion of ASA-positive and C-bound sperm.

Electron Microscopic observation on the semen of HIV-positive men

Despite well-documented studies showing HIV transmission by and isolation from semen, relatively little information is available concerning the morphology and cellular characteristics of the semen of HIV positive individuals. We have there fore examined the semen of HIV infected patients with electron microscopy in order to determine cellular ultrastructure and possible sites of virus in this material. Patients were assayed for HIV in peripheral blood, and cell free plasma, as well as semen and CD-4-T-cells were counted. Ejaculates were obtained from 9 HIV positive individuals. Five had symptomatic HIV infections: three had AIDS and were on zidovudine therapy, two had ARC (AIDS Related Complex); four were asymptomatic. All were HIV culture positive from blood, and two were HIV culture positive from semen. Table 1 details the disease category and HIV assay data in these patients. Electron microscopy revealed that semen from the symptomatic AIDS group was infiltrated with macrophages and other white cells with extensive phagocytosis of sperm and other debris (Figure 1).

The Epithelial Lining of the Bovine Ejaculatory Duct

The bovine ejaculatory duct is lined by a pseudostratified columnar epithelium. Two cell types are present: small basal cells and columnar principal cells in different functional states. The basal cells are able to accumulate lipid material. The principal cells are observed in a less active state and in a state of either increased endocytosis and fluid uptake or active spermiophagy. Endocytotically active cells are characterized by an apical brush border and a system of microvesicles, multivesicular bodies and lysosomal dense bodies. Cells involved in phagocytosis of spermatozoa are mostly provided with a smooth apical border, an expanded Golgi apparatus, many phagocytic vacuoles and condensing phagolysosomes.

Failure to demonstrate significant antisperm antibodies in peritoneal fluid of patients with endometriosis

Endometriosis, even in mild cases, decreases monthly fecundity. Immunologic disorders have been suggested as the mechanism. In light of possible increases in serum autoimmune antibodies, increased peritoneal macrophages, and increased sperm phagocytosis associated with this disease, we postulated that peritoneal fluid antisperm antibodies would be increased and might be the cause of increased sperm phagocytosis and its associated infertility. Peritoneal fluid, from 18 patients with endometriosis and 10 infertile controls, was tested with the antisperm antibody immunobead test validated for peritoneal fluid. One of 18 patients with endometriosis and none of 10 controls had antisperm antibodies present. Therefore, increased sperm phagocytosis is unlikely a result of peritoneal antisperm antibodies in endometriosis patients.