An IgG-Fc binding protein in seminal fluid

Prognostic Role of Prolactin-Induced Protein (PIP) in Breast Cancer

Prolactin-inducible protein (PIP), also referred to as gross cystic disease fluid protein 15 (GCDFP-15), has been a trending topic in recent years due to its potential role as a specific marker in breast cancer. PIP binds to aquaporin-5 (AQP5), CD4, actin, fibrinogen, β-tubulin, serum albumin, hydroxyapatite, zinc α2-glycoprotein, and the Fc fragment of IgGs, and the expression of PIP has been demonstrated to be modulated by various cytokines, including IL4/13, IL1, and IL6. PIP gene expression has been extensively studied due to its captivating nature. It is influenced by various factors, with androgens, progesterone, glucocorticosteroids, prolactin, and growth hormone enhancing its expression while estrogens suppress it. The regulatory mechanisms involve important proteins such as STAT5A, STAT5B, Runx2, and androgen receptor, which collaborate to enhance PIP gene transcription and protein production. The expression level of PIP in breast cancer is dependent on the tumor stage and subtype. Higher expression is observed in early-stage tumors of the luminal A subtype, while lower expression is associated with luminal B, basal-like, and triple-negative subtypes, which have a poorer prognosis. PIP expression is also correlated with apocrine differentiation, hormone receptor positivity, and longer metastasis-free survival. PIP plays a role in supporting the immune system's antitumor response during the early stages of breast cancer development. However, as cancer progresses, the protective role of PIP may become less effective or diminished. In this work, we summarized the clinical significance of the PIP molecule in breast cancer and its potential role as a new candidate for cell-based therapies.

Insights into the Antibacterial Activity of Prolactin-Inducible Protein against the Standard and Environmental MDR Bacterial Strains

Background: Prolactin inducible protein (PIP) is a small secretary glycoprotein present in most biological fluids and contributes to various cellular functions, including cell growth, fertility, antitumor, and antifungal activities. Objectives: The present study evaluated the antibacterial activities of recombinant PIP against multiple broad-spectrum MDR bacterial strains. Methods: The PIP gene was cloned, expressed and purified using affinity chromatography. Disk diffusion, broth microdilution, and growth kinetic assays were used to determine the antibacterial activities of PIP. Results: Disk diffusion assay showed that PIP has a minimum and maximum zone of inhibition against E. coli and P. aeruginosa, respectively, compared to the reference drug ampicillin. Furthermore, growth kinetics studies also suggested that PIP significantly inhibited the growth of E. coli and P. aeruginosa. The minimum inhibitory concentration of PIP was 32 µg/mL for E. coli (443), a standard bacterial strain, and 64 µg/mL for Bacillus sp. (LG1), an environmental multidrug-resistant (MDR) strain. The synergistic studies of PIP with ampicillin showed better efficacies towards selected bacterial strains having MDR properties. Conclusion: Our findings suggest that PIP has a broad range of antibacterial activities with important implications in alleviating MDR problems.

Prostasomes: Their Characterisation: Implications for Human Reproduction: Prostasomes and Human Reproduction

The prostate is a principal accessory genital gland that is vital for normal fertility. Epithelial cells lining the prostate acini release in a defined fashion (exocytosis) organellar nanosized structures named prostasomes. They are involved in the protection of sperm cells against immune response in the female reproductive tract by modulating the complement system and by inhibiting monocyte and neutrophil phagocytosis and lymphocyte proliferation. The immunomodulatory function most probably involves small non-coding RNAs present in prostasomes. Prostasomes have also been proposed to regulate the timing of sperm cell capacitation and induction of the acrosome reaction, since they are rich in various transferable bioactive molecules (e.g. receptors and enzymes) that promote the fertilising ability of sperm cells. Antigenicity of sperm cells has been well documented and implicated in involuntary immunological infertility of human couples, and antisperm antibodies (ASA) occur in several body fluids. The propensity of sperm cells to carry attached prostasomes suggests that they are a new category of sperm antigens. Circulating human ASA recognise prostasomes, and among 12 identified prostasomal antigens, prolactin- inducible protein (95 %) and clusterin (85 %) were immunodominant at the expense of the other 10 that were sporadically occurring.

Protein profile of the seminal plasma of collared peccaries (Pecari tajacu Linnaeus, 1758)

This study was conducted to characterize the major proteins of the peccary seminal plasma, based on the semen samples collected from nine adult and reproductively sound animals. Our approach included the use of two-dimensional electrophoresis followed by Coomassie blue staining and analysis of polypeptide maps with PDQuest Software (Bio-Rad). Proteins were identified by tandem mass spectrometry (LC-MS/MS). We detected 179 protein spots per gel and 98 spots were identified by mass spectrometry, corresponding to 23 different proteins. The combined intensity of those spots accounted for 56.2±6% of the intensities of all spots and 60.9% of the intensities of spots presented in every protein map. Protein spots identified as clusterin represented 19.7±8.3% of the integrated optical densities of all spots detected in the seminal plasma maps. There was a negative association (r=-0.87; P<0.05) between the intensity of a clusterin spot and the percentage of sperm with functional membrane. Spermadhesin porcine seminal plasma protein 1 and bodhesin 2 comprised 5.4±1.9 and 8.8±3.9% of the total intensity of all spots respectively. Many proteins appeared in a polymorphic pattern, such as clusterin (27 spots), epididymal secretory glutathione peroxidase (ten spots), inter-α-trypsin inhibitor (12 spots), and IgG-binding protein (ten spots), among others. In conclusion, we presently describe the major seminal plasma proteome of the peccary, which exhibits a distinct high expression of clusterin isoforms. Knowledge of wild species reproductive biology is crucial for an understanding of their survival strategies and adaptation in a changing environment.

Comparative proteomic study between human normal motility sperm and idiopathic asthenozoospermia

PURPOSE

Idiopathic asthenozoospermia is considered as one of the causes of male infertility and characterized by reduced sperm motility. For a better determination of pathogenic mechanism of asthenozoospermia, the exploration of differentially expressed proteins in normal sperm motility and idiopathic asthenozoospermia was conducted in our study.

METHODS

Sperm proteins were extracted and isolated by two-dimensional electrophoresis. All significantly changed protein spots were picked up from 2D gels and identified by tandem mass spectrometry. Sixteen of the thirty-three total differentially expressed protein spots were successfully identified by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry.

RESULTS

Sixteen proteins identified belonged to 15 unique protein groups. GRP78, lactoferrin, SPANXB, PGK2, flagellin, DJ-1, XPA binding protein 2, CAB2, GPX4, and GAPDH were the first to be identified as differentially expressed proteins in idiopathic asthenospermia patients. Meanwhile, the analysis of quantitative RT-PCR was carried out to compare the protein levels, and the results indicated that the expression levels of the gene and protein were not entirely consistent.

CONCLUSIONS

These experimental results expand the scope of the protein database, generating targets for further investigation of the pathogenic mechanism of idiopathic asthenozoospermia.

Human seminal plasma antibody-binding proteins

PROBLEM

The physiological role of antibody-binding proteins in human seminal plasma and the potential role of these proteins in infertility is relatively unknown.

METHOD OF STUDY

Literature on antibody-binding proteins.

RESULTS

Human seminal plasma has a diverse effect on immune function of the reproductive tracts. This review describes (1) the presence of receptors like proteins that can react with monoclonal antibodies against Fcgamma receptors III (Fcgamma RIII) but are distinctly different from Fcgamma RIII; (2) IgG binding factors (IgGBF), a group of low molecular weight proteins that are capable of binding human IgG; (3) other proteins that can bind antibodies, such as prolactin-inducible protein and three other novel proteins that we have discovered. These proteins potentially all have the ability to reduce the interactions between antisperm antibodies and effector components of the immune system, such as phagocytic cells.

CONCLUSIONS

Human seminal plasma contains proteins that can bind antibodies. However, to date our knowledge of these proteins especially, whether they have a physiological role in either the male and female reproductive tracts is limited.

Human seminal plasma prolactin-inducible protein is an immunoglobulin G-binding protein

Antisperm antibodies (ASA) are present in 20% of couples seeking treatment for infertility. Antibody-binding proteins in seminal plasma may protect sperm from ASA-induced damage. We have previously isolated several IgG-binding proteins from human seminal plasma using IgG affinity chromatography. Here, we report another such protein which we have identified by amino acid sequencing and confirmed by western blotting to be prolactin-inducible protein (PIP). PIP binds via the Fc fragment of IgG. We have determined the level of PIP in normal seminal plasma to be 3.4 mg/ml (interquartile range 2.0-4.4 mg/ml). We have found there is no difference in the mean level of PIP in seminal plasma from fertile or infertile men regardless of ASA status. PIP was shown to exist in several isoforms in seminal plasma by Western blot. There is a complex pattern of PIP isoform variability in seminal plasma from fertile and infertile men but one multimeric form of PIP was absent from the seminal plasma of men with ASA who were fertile. This may reflect consumption of PIP in these men. The physiological function of PIP remains unknown, but the ability of PIP to bind IgG-Fc suggests PIP may have an immunomodulatory role.

Antibody-binding proteins in human seminal plasma

PROBLEM

The significance of antibody-mediated infertility is unclear and complicated by the finding of that antisperm antibodies are found both in fertile and infertile couples. Seminal plasma contains immunosuppressive factors, one such factor may be antibody-binding proteins (ABP's).

METHOD OF STUDY

Antibody-binding-proteins were purified using human IgG or IgG-Fc affinity chromatography columns. The purified antibody-binding proteins were characterized by their molecular weights, partial amino acid sequences, and immunoreactivities.

RESULTS

Three proteins of molecular weight 74, 70 and 55 kDa and other low molecular weight proteins specifically bound to the IgG or IgG-Fc affinity columns demonstrating Fc-binding specificities. These proteins were not FcgammaRIII, IgG, or fragments of these proteins by their behaviors under reducing conditions, Western blot, and partial amino acid sequence analyses. Amino acid sequence data demonstrated some of these proteins to be novel.

CONCLUSIONS

We have isolated and partially characterized several ABP's from seminal plasma. The IgG-binding proteins we have identified may protect spermatozoa against antibody-mediated damage by conferring protection to antibody-coated spermatozoa. If this hypothesis holds true, differences in the level or function of these ABP's may alter the status of fertility.

Decreased suppression of antibody-dependent cellular cytotoxicity by seminal plasma in unexplained infertility

OBJECTIVE

To determine whether seminal plasma (SP) from unexplained infertile males has different suppressive activity on antibody-dependent cellular cytotoxicity (ADCC) than SP from fertile males or SP from males of couples with known infertility factor.

DESIGN

Comparative clinical/experimental study.

SETTING

In vitro fertilization program in a university hospital and a hospital research laboratory.

PATIENT(S)

A total of 245 SP samples from 174 infertile and 16 fertile couples were compared.

INTERVENTION(S)

SP suppression of ADCC was measured by using human 51chromium-labeled red blood cells (RBC), sensitized with IgG-rabbit-anti-human-RBC as targets and peripheral blood lymphocytes as effector cells.

MAIN OUTCOME MEASURE(S)

Suppressive activity of each sample was determined by calculating 51Cr-release in the presence and absence of SP.

RESULT(S)

When analyzed with respect to sperm number, motility, and morphology, suppressive activities of samples with normal semen analyses (n = 142) were significantly higher (x = 37% +/- 14%) than suppressive activities of abnormal samples (n = 103; x = 32% +/- 13%). There was no strong correlation of suppressive activity to other semen parameters. Within the andrologically normal males, SP from the unexplained infertile couples (n = 15) showed significantly lower suppressive activity (x = 24% +/- 11%) compared with the SP from fertile males (n = 16; x = 35% +/- 13%) and from couples with female infertility factor (n = 65; x = 39% +/- 14%).

CONCLUSION(S)

Loss of suppressive activity is associated with unexplained infertility, even in male patients who previously were considered normal by traditional methods of semen analysis.

Inhibitory effects of human seminal plasma on an ELISA used to detect anti-sperm antibodies: implications for the determination of sperm quality

The in vitro inhibitory effect of human seminal plasma on an ELISA used to detect anti-sperm antibodies have been observed. The mean inhibition rate of seminal plasma samples from 75 men was 61.5+/-23.1%. The inhibition rate of 29 samples from normal sperm group was 71. 14+/-18.25%, while that of 46 samples from the abnormal sperm group was 55.43+/-23.98%. The results show that human seminal plasma from semen with high quality sperms possesses a high inhibitory rate to anti-sperm antibody reactions, suggesting its efficiency for immunosuppression of humoral immune reactions. Its possible implications are discussed.

Isolation and purification of an early pregnancy factor-like molecule from culture supernatants obtained from lymphocytes of pregnant women: II. Identification of the molecule as a Fc-receptor-like molecule: a preliminary report

PURPOSE

Early pregnancy factor (EPF)-like activity from culture supernatants obtained from stimulated lymphocytes of pregnant women was characterized and identified.

METHODS

The enzyme-linked immunosorbent assay depending on the presence of "Fc" receptors on bovine spermatozoa was used to identify the EPF-like molecule purified by gel filtration and reverse-phase high-performance liquid chromatography.

RESULTS

The results indicated that the crude lymphocyte culture supernatant, the EPF-positive G IV fraction obtained on gel filtration, and the EPF-positive reverse-phase high-performance liquid chromatography protein readily bound with the different concentrations of aggregated human gamma-globulin in a manner similar to that in which the standard control of aggregated human gamma-globulin binds to the bovine spermatozoa.

CONCLUSIONS

EPF-like activity synthesized and secreted by lymphocytes during pregnancy may be a Fc-receptor-like molecule.

beta-Microseminoprotein/prostatic secretory protein is a member of immunoglobulin binding factor family

Human seminal plasma contains a factor that binds human IgG, designated as immunoglobulin binding factor (IgBF). Under reducing condition IgBF interacts with anti-Leu-11b, a murine monoclonal antibody raised against human FcgammaRIII/CD16. IgBF shows no binding activity under non-reducing condition. Three components having IgBF activity were separated by HPLC and their amino acid sequences determined. The main IgBF showed structural identity to beta-microseminoprotein (beta-MSP), prostatic secretory protein of 94 amino acids (PSP94) and beta-inhibin. The slight variation in the reported sequences of these proteins has been attributed to analytical error. In the present study the molecular masses of main IgBF and beta-MSP/PSP94 were found to be identical by mass spectrometry. In addition, a large component of IgBF and a shorter beta-MSP consisting of 93 amino acids were identified. The binding of beta-MSP for human IgG and anti-Leu-11b antibody is demonstrable only under reducing condition, determined by Western blot analysis. The present data clearly show that IgBF is a family composed of at least three isoforms. One of the members is beta-MSP/PSP94. This family should be designated as IgBF.

Presence of immunoglobulin binding factor on human sperm surface as sperm coating antigen

The presence of IgBF as a sperm-coating antigen was demonstrated by showing that anti-IgBF antibodies agglutinate and immobilize human sperm and by localizing IgBF on sperm surface by immunofluorescence staining. Several components interacting with sperm immobilizing antibodies, known to be involved in infertility, are sperm-coating antigens. Anti-IgBF antibody in vitro did not block the ability of human sperm to penetrate human zona pellucida and zona-free hamster egg. Anti-IgBF activity of sera obtained from infertile women did not correlate with the titers of anti-sperm antibodies measured by the sperm immobilization test. IgBF is a sperm-coating antigen and may play a role in suppressing antibody production against alloantigenic sperm in the female reproductive tract.

Complement-inhibiting activity of human seminal plasma and semen quality

Human seminal plasma (SP) contains potent complement inhibitors. This study examined the complement-inhibiting activity of individual SP samples from 118 patients with infertility and analyzed them in relation to various semen parameters. When 25% complement-inhibiting activity was considered the cut off value, less than 1 SD unit from the mean percentage of inhibition of SP samples with normal semen quality, 32 samples (27%) showed low inhibiting activity. Among the lower group, incidences of patients with asthenozoospermia (66%) and oligozoospermia (31%) were significantly (p < .01) higher than those (36 and 10%) in the group whose SP showed significant inhibiting activity. Partial characterization revealed that the component responsible for complement inhibition was heat labile, trypsin resistant, high molecular weight (>10 kD) glycoprotein that can inhibit alternative as well as classical complement pathways. Furthermore, since in the majority of SP samples the anticomplementary activity was blocked by monoclonal antibody against membrane cofactor protein (MCP) or decay accelerating factor (DAF), the complement-inhibiting factors that were identified are likely to be MCP and/or DAF, which are known to be present in human SP. These results suggest that complement-regulatory proteins in SP such as MCP and DAF may protect sperm cells against complement attack in the male reproductive tract.

High implantation rate and consequently high pregnancy rate by in vitro fertilization-embryo transfer treatment in infertile women with antisperm antibody

OBJECTIVE

To examine the effect of antisperm immunity on postfertilization steps, such as implantation of embryos and fetal growth in IVF-ET treatment of women with sperm-immobilizing antibodies.

DESIGN

Retrospective analysis of clinical laboratory data.

SETTING

The IVF-ET program of the Department of Obstetrics and Gynecology. The University of Tokushima, School of Medicine.

PATIENTS

Eighteen women with sperm-immobilizing antibodies and 122 infertile patients with nonimmune etiology as controls. Infertile couples due to a male factor and with unknown etiology were excluded.

INTERVENTIONS

All patients received the same IVF-ET program with GnRH agonist.

MAIN OUTCOME MEASURES

Rates of fertilization and cleavage, implantation rate per embryo transferred and pregnancy rate (PR) in both test and comparison groups.

RESULTS

The rate of fertilization in the antisperm group (61.3%) was significantly lower than that in the comparison group (76.8%). But the implantation rate per embryo transferred (23.5%) and consequently the modified PR per oocyte recovery procedure (34.4%) in immunologically infertile women were significantly higher than those in the comparison group (7.9% and 17.8%, respectively).

CONCLUSIONS

Although sperm-immobilizing antibodies prevent sperm-egg interaction, they do not seem to have any adverse effects on achievement of pregnancy. Moreover, the existence of antisperm immunity in woman with antisperm antibodies is suggested to be favorable for successful pregnancy by the IVF-ET procedure.

A cluster of tuberculosis among crack house contacts in San Mateo County, California

In March 1992, a cluster of 89 persons with tuberculosis infection was identified in San Mateo County, California. Thirteen persons (15%), including 11 children, were diagnosed with active pulmonary tuberculosis. All contacts were African Americans who resided in or visited one of two houses used for crack cocaine smoking or dealing. The patient with the index case, a male infected with human immunodeficiency virus, contributed to the transmission of tuberculosis as a transient resident of several dwellings. Public health authorities applied unique intervention methods to control the outbreak, including the use of a mobile health van. Further innovative strategies will be necessary to meet the challenge of this reemerging disease.

Identification of human seminal plasma components that bind IgG2 variant

Human seminal plasma (hsp) contains soluble proteins capable of binding immunoglobulin (Ig) G. Two novel components with estimated molecular sizes of 90 and 21 kD interact specifically with a variant of IgG2 found in 20% of human sera tested. The common IgG2 present in human sera and other subclasses of IgG did not bind with the hsp components. The present findings shows that the interacting IgG2 is a variant and not the common or prevalent species. The 90-kD component of hsp with IgG2 binding property is probably a nonglycosylated protein, whereas the 21-kD component is a glycosylated protein. The 90- and 21-kD components were detected in 20% of hsp specimens tested. Thus they are not present in the majority of hsp. Since the IgG2 binding components of hsp and the serum IgG2 variant are found in 20% of men and 20% of individuals, respectively, they can be used as genetic markers.

Immunoglobulin binding factor: a new tumor marker for prostatic tumors

Human seminal plasma contains an immunoglobulin gamma binding factor (IgBF) with an estimated molecular weight of 16 kD under reducing condition. IgBF was detected only in the prostate, including benign prostatic hypertrophy (BPH) and neoplasm. The present study was performed to determine whether IgBF is a useful prostatic marker. Serum IgBF levels were measured in patients with prostatic tumors and in control patients without tumor by radioimmunoassay. Serum prostatic-specific antigen (PSA), the standard prostatic marker, was also determined. Serum IgBF levels in patients with prostate cancer were significantly higher than those in age-matched controls (P < 0.05). Also, patients with BPH tended to have elevated IgBF levels than the controls, although the values were not statistically significant. In control patients, serum IgBF levels increased with advancing age. There was no correlation between serum levels of IgBF and PSA in patients with prostate cancer. Using cut-off level at 28.5 ng/ml (2 S.D. above the mean IgBF level of age-matched control), the sensitivities were 41.2% (7/17) for prostate cancer, 23.1% (6/26) for BPH, and 5.6% (1/18) for control patients. In conclusion, serum IgBF is a useful marker in the diagnosis of patients with prostatic tumor, and in evaluating the course of treatment.

Binding of a specific subclass of immunoglobulins by a human seminal plasma component

Human seminal plasma contains a component that binds immunoglobulins (Ig). The Ig binding factor was purified by ammonium sulphate precipitation, preparative isoelectrofocusing and gel filtration chromatography and found to bind strongly human IgGl and mouse IgM. This seminal plasma component may possess immunosuppressive activity and may modulate the activities of the immunosurveillance system of the reproductive tract.

Immunoglobulin binding factor in human seminal plasma: immunological function

Human seminal plasma contains a protein with an estimated molecular weight of 16 kd that binds serum immunoglobulin gamma (IgG) and is named IgG binding factor (IgBF). Purified IgBF specifically suppressed pokeweed mitogen-induced lymphocyte blastogenesis, having little or no effect on lymphocyte blastogenesis stimulated with phytohemagglutinin or Concanavalin A; antibody-dependent cell-mediated cytotoxicity; natural killer cell activity; or complement-dependent cytotoxicity of antibodies against sperm. It would appear that IgBF may suppress activation of B cells in the male and female genital tract.

The immune response to coitus and conception

It is well recognized that cells or tissues exchanged between genetically dissimilar members of the same species will be destroyed by a specific immune response. This process of destruction is initiated by the expression of histocompatibility antigens on the surface of the donor cells which provoke a reaction by the immune system of the recipient. Successful reproduction even through a fundamental process is thought to expose the female to significant antigenic challenge. Numerous hypotheses have been proposed to account for the survival of the semiallogeneic conceptus, although the immunological consequences of coitus are frequently ignored. The possible immunosuppressive role of seminal plasma in normal reproduction is clearly of great clinical importance. Its exclusion from the in vitro fertilization techniques of human reproduction may partially account for the high failure rates associated with this form of assisted reproduction. Its presence in the normal ejaculate may explain the vulnerability of the female reproductive tract to virally inducted neoplasms and be a relevant factor in the etiology of the acquired immune deficiency syndrome.

Immunoglobulin binding factor of seminal plasma: a secretory product of human prostate

To determine the source of the immunoglobulin binding factor (IBF) in seminal plasma, extracts of testis and accessory male sex organs were prepared and analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblot. The detection reagents used were human and mouse serum Ig, monoclonal anti-Leu 11b antibodies, and polyclonal rabbit anti-IBF antibodies. Of the tissues examined, only the prostate, including benign hypertrophy and adenocarcinoma, contained IBF. These findings suggest that IBF is a secretory product of the prostate.

Leukocytospermia and function of the seminal vesicles on seminal quality

OBJECTIVE

To determine possible relationships between number of leukocytes, function of seminal vesicles, and seminal quality.

DESIGN

The study was carried out on men who consecutively attended an infertility clinic between June 1989 to June 1991.

SETTING

This study was conducted in a private immunological center for infertility, a tertiary care center, The Centro Immunológico-Sección Esterilidad y Reproducción.

PATIENTS

Semen samples from 280 infertility patients attending an Immunological Center for Infertility were analyzed.

MAIN OUTCOME MEASURE

We evaluated the effect of leukocytospermia in the presence of normal or abnormal function of seminal vesicles on seminal quality.

RESULTS

Sperm count, percent of motile sperm, and percent of sperm vitality were significantly reduced when both leukocytospermia and hypofunction of seminal vesicles were present (P less than 0.01). Leukocytospermic subjects with normal function of seminal vesicles showed similar seminal parameters to those nonleukocytspermics. The incidence of subjects with antisperm antibodies measured by direct immunobeads was significantly higher in leukocytospermic men with hypofunction of seminal vesicles. No differences in the incidence of antisperm antibodies with nonleukocytospermic samples were observed in those with both leukocytospermia and normal function of seminal vesicles.

CONCLUSIONS

These data provide evidence that white blood cells were deleterious for seminal quality when seminal vesicles were also affected.

Extracellular organelles (prostasomes) are immunosuppressive components of human semen

Numerous reports have ascribed immunosuppressive activity to human seminal plasma and there is growing agreement that much of this activity can be accounted for by the very high levels of E series prostaglandins present (up to 300 microM 19-hydroxy prostaglandin E). However not all suppressive activity is due to prostaglandin since several reports have appeared of high molecular weight active substances and we have found that stripped seminal plasma is still effective in inhibiting the mitogen-induced proliferation of lymphocytes. In this study such immunosuppressive activity has been separated by molecular size fractionation and the activity has been found to be particulate and corresponded to the previously reported prostasomes. These are trilaminar to multilaminar vesicles (150 nm diameter) which are secreted by the prostate. Pure preparations of prostasomes inhibited mitogen-induced lymphoproliferation in a dose-dependent manner with a concentration of prostasomes equivalent to 40% of that seen in seminal fluid giving 69% suppression of thymidine incorporation. The suppressive activity survived boiling and therefore was unlikely to be due to enzymatic action associated with these organelles. Interaction with the accessory cells, involved in full development of the lymphoproliferation induced by mitogen, was indicated and this possibility was supported by the demonstration of a direct effect of prostasomes on macrophage function using a mouse macrophage cell line. The prostasomes in semen may play a complementary role to the prostaglandins in neutralizing the immune defences of the female reproductive tract. This combination would allow the alloantigenic spermatozoa the best chance of achieving fertilization, but at the same time leave the recipient open to any infection present in the semen.

Immunoglobulin-Fc binding factor in human male reproductive organs

Human seminal plasma, testis, seminal vesicle, epididymis, and prostate contain a component with an estimated Mr of 20 kD that binds human immunoglobulin-Fc. The factor did not bind goat-IgG-Fc, immunoglobulins of human, rat, mouse, goat, horse, or rabbit sera and did not interact with antibodies raised against Fc gamma receptors. The present findings show that this Fc binding factor in seminal plasma is a secretory product of the testis and accessory sex organs. It binds human Ig-Fc but does not meet the criteria of an Fc receptor. Additional IgG-Fc binding proteins with estimated Mr of 90, 88, and 86 kD were detected in the prostate, testis, and seminal vesicle, respectively.

Structural identity of immunoglobulin binding factor and prostatic secretory protein of human seminal plasma

The amino acid sequence of the N-terminus of the immunoglobulin binding factor of human seminal plasma was determined. The initial 30 amino acids showed complete identity with that of prostatic secretory protein, beta-microseminoprotein and beta-inhibin. In conclusion, these proteins are probably a single entity.

Zinc-protein from rat prostate fluid binds epididymal spermatozoa

The detection and the isolation of a zinc-protein from the secretion of the rat dorsolateral prostate is described. The purification procedure, based on gel filtration and cationic exchange chromatography, allowed to separate a minor protein (Mr approximately 66,000) from free zinc ions and other secretory components. Two zinc ions were estimated to be associated with one molecule of isolated protein. The zinc-protein was labelled with 125I and then incubated at 37 degrees C with spermatozoa from rat epididymal cauda. Time-dependent in vitro binding of the radioactive protein to sperm cells was demonstrated. This binding was not affected by the presence of proteins from the seminal vesicle during the incubation, while it was blocked in the presence of an excess of unlabelled zinc-protein. After binding, the labelled spermatozoa were treated with a buffer containing 0.5% sodium deoxycholate and 40 mM EDTA; only very small amounts of label were removed from the cells, thus suggesting that the zinc-proteins were kept on the plasma membrane by interactions which do not involve merely hydrophobic bonds.

Identification of IgG and Fc-binding proteins in human seminal plasma and sperm

Human seminal plasma contains two novel soluble proteins capable of binding IgG and Fc, but not Fab. The IgG- and Fc-binding proteins were identified by immunoblotting using IgG of various species, Fc and Fab fragments. Their estimated molecular sizes are 16-kD and 20-kD. The monoclonal antibody (MAb), Leu 11b, raised against Fc gamma RIII interacts with the 16-kD protein, whereas other mAbs (32.2, IV.3, and 3G8) raised against FcR did not. The 16-kD protein is capable of binding IgG of several species (human, mouse, rabbits, and goat), whereas the 20-kD protein interacted only with human IgG-Fc fragment. The 16-kD IgG and the 20-kD Fc-binding proteins were found in the PBS extract of human sperm. Human seminal plasma/sperm contain an IgG- and a Fc-binding protein with estimated Mr of 16 and 20 kD, respectively.

Immunological role for seminal plasma in insemination and pregnancy

Insemination confronts the female with paternally derived alloantigens and represents an immunological challenge preceding fertilization and implantation. Current evidence suggests a role for seminal plasma in regulating maternal immunity for insemination and pregnancy. In vitro seminal plasma has been shown to suppress T- and B-cell proliferation, neutrophil and macrophage phagocytic activity, as well as killer cell activity. Seminal plasma interacts with complement components C1 and C3 and contains factors that specifically bind the Fc region of IgG. These in vitro findings suggest possible seminal plasma-suppressive effects on female alloimmune responses after insemination. Seminal plasma also contains allotypic TLX antigens that could prime mothers prior to fertilization. Such priming effects for pregnancy acceptance are supported by improved implantation rates in controlled clinical trials using timed vaginal exposure to semen during in vitro fertilization or gamete intrafallopian transfer treatment cycles.

Detection of immunosuppressive activity in human seminal plasma by an immunobioassay

Recent evidence has shown that under in-vitro conditions human seminal plasma can interfere directly or indirectly with the function of cells of the immune system. It is however, questionable whether the results generated in vitro can be related directly to in-vivo activity. We have therefore standardized an in-vivo immunobioassay to detect the immunosuppressive property of human seminal plasma using adoptive transfer of contact sensitivity to a specific antigen such as dinitrofluorobenzene. Our results indicate that when sensitized lymphoid cells were incubated in vitro with human seminal plasma, their ability to transfer the delayed hypersensitivity in non-sensitized mice was suppressed or inhibited in comparison with the controls. The percentage suppression varied with different samples but the results indicate clearly that the immunosuppressive properties of human seminal plasma can be demonstrated using an in-vivo immunoassay.

Interaction of proteins RSV IV and RSV V in rat seminal vesicle secretion

The RSV IV polypeptide, molecular weight ratio (Mr = 10,000), which is produced by the rat seminal vesicle, has previously been suggested to be associated with another polypeptide in the gland secretion (Higgins et al., '76). This study provides that RSV IV is a component of a protein shown by immunoassays, electrophoresis, and amino acid composition analysis to contain, together with RSV IV, the seminal vesicle secretory RSV V polypeptide (Mr = 13,000). This RSV IV-RSV V complex (namely CFS protein) had an isoelectric point at pH 7.2 and an approximate molecular weight of 22,000 daltons. This complex inhibits the previously reported in vitro binding of the isolated RSV IV to epididymal sperm cells, thus suggesting a functional role for the RSV IV-RSV V interaction.

Human seminal plasma is a potent inhibitor of natural killer cell activity in vitro

The effect of human seminal plasma on the natural killer (NK) activity of human peripheral blood leukocytes in vitro has been investigated. Small concentrations (as low as 0.01% v/v) of seminal plasma were found to inhibit the ability of human peripheral blood leukocytes to lyse K562 target cells. These inhibitory effects were observed with seminal plasma donations from normal and infertile individuals, including those who had been vasectomised. The inhibition noted appeared to be independent of the presence of antisperm antibodies which could conceivably cross-react with NK cells. Furthermore, the factors responsible survived boiling for 15 min and could not be absorbed out with K562 target cells. These profound inhibitory effects might be relevant to malignancy of the urogenital tract and the defence against sexually transmitted disease.

The next 10 years in the treatment of pelvic infections

The future developments in the treatment of pelvic infections in women are based on recent changes. There is an expanded knowledge of the complex multibacterial nature of pelvic infections, the clinical view of salpingitis has radically changed, and there have been great modifications in antibiotic treatment strategies with particular emphasis on anaerobes and Chlamydia. In the next 10 years, the following new developments may be expected. In the diagnosis of pelvic infection, there will be new efforts to have better clinical tests and the use of nonspecific and specific laboratory tests. The rapid identification of Neisseria gonorrhea, group B beta-hemolytic Streptococcus, Chlamydia, and Bacteroides fragilis would be an important laboratory aid. The treatment of pelvic infection will not be significantly altered by the introduction of new antibiotics. There will be an emphasis on new combinations of currently available antibiotics and studies that focus on the long-term follow-up of treated patients. In the understanding of the pathophysiology of pelvic infections, the importance of the spermatozoa as a carrier of bacteria and the potent immunosuppression due to seminal fluid will be investigated in detail, along with a greater emphasis on treatment of the male.

Immunological studies on seminal plasma proteins of the Indian buffalo and cattle

Seminal plasma proteins of the Indian buffalo and cattle were immunologically investigated using rabbit antibuffalo seminal plasma serum, rabbit anticattle seminal plasma serum (unabsorbed and absorbed), gel diffusion, and immunoelectrophoretic analysis. At least 9-12 and 7-10 different proteins, respectively, were present in the seminal plasma of the buffalo and cattle. Albumin and IgG were identified in both the species. At least 4-6 seminal plasma proteins of the buffalo and cattle were antigenically similar to their blood serum proteins. Using absorbed rabbit antibuffalo seminal plasma serum and rabbit anticattle seminal plasma serum, at least 6-7 and 5-6 seminal plasma specific proteins, respectively, were observed in the buffalo and cattle seminal plasma. Antigenically these proteins were different from the blood serum proteins of these two species. The origin and biological significance of seminal plasma proteins are discussed.

Detection and characterization of immune complexes in the circulation of infertile women

The incidence of circulating immune complexes (CICs) was evaluated in sera from 39 female partners of infertile marriages and from 38 fertile women. Fifteen (38%) of the infertile women had CICs, as determined by the Raji cell assay, in levels ranging from 300 to 8000 micrograms/ml; whereas only 1 (3%) of the fertile women displayed CICs (P less than 0.001). Analysis of the CICs from nine of the women following polyethylene glycol precipitation and acid dissociation revealed that four contained C1q and three contained an antigen reactive with rabbit antibody to human spermatozoa. These latter three women all lacked free sperm antibody, as determined by enzyme-linked immunosorbent assay and agglutination. Thus, CICs are not uncommon as a manifestation of infertility in females. Their presence may lead to an underestimation of sperm antibody levels and may be indicative of underlying infection or autoimmunity.

Rectal insemination modifies immune responses in rabbits

Weekly deposition of pooled rabbit semen into the rectum in healthy male rabbits resulted in the appearance of immune complexes and antibodies to sperm and to peripheral blood lymphocyte antigens. It also led to a decreased ability to mount a humoral immune response to T lymphocyte-dependent antigens, keyhole limpet hemocyanin, and sheep red blood cells. These findings suggest that repeated rectal deposition of semen may compromise some aspects of the immune system.