Characterization of clonogenic stromal cells isolated from human endometrium

Human endometrium is an object of extensive restructuring and remodeling during the female reproductive life and it is quite tempting to assume that these periodic changes happen with the participation of cells that should have the basic characteristics of multipotent cells. The aim of this study was to search for the presence of cells with plastic adherence, clonogenicity, and differentiation in human endometrium. To this end, human endometrial stromal cells were cultured in vitro for more than 15 passages. Flow cytometry analysis of the cultured cells showed that they were positive for CD29, CD73 and CD90, which are considered to be the markers of cells with mesenchymal origin. The cells were negative for the hematopoietic cell markers (CD45, CD34, CD14, CD3, CD19, CD16/56, and HLA-DR). Further, it was shown that the cultured cells had 15% clonogenic efficiency and could be induced to differentiate into adipogenic cells containing typical lipid-rich vacuoles. These results demonstrate that the human endometrium contains a low number of cells with the characteristics of endometrial stromal stem/progenitor cells, which seem to belong to the family of the mesenchymal stem cells. It can be speculated that these cells are engaged into the monthly restructuring and remodeling of human endometrium.

Dynamics of membrane translocation of phosphatidylserine during apoptosis detected by a monoclonal antibody

Translocation of phosphatidylserine (PS) to the outer leaflet of the cellular membrane seems to be a key step in apoptosis and cell activation. In this paper, the production and characterization of a monoclonal antibody designated as Mab 1H6 is described which does not show cross reactivity with others anionic phospholipids. It is demonstrated that Mab1H6 can recognize externalized PS at early stages after the induction of apoptosis shown by both flow cytometry and immunofluorescence. Our results show that translocation of PS can be detected as early as 5 min by immunofluorescence and 10 min by flow cytometry after the treatment of cells and a specific dynamics is observed concerning the location and distribution of the staining. These data prove that antibody Mab 1H6 can be used as a specific probe for detection of PS translocation.

Lupus-specific kidney deposits of HSP90 are associated with altered IgG idiotypic interactions of anti-HSP90 autoantibodies

Previous studies have shown that autoantibodies to heat shock protein 90 (HSP90) are elevated in a significant proportion of patients with systemic lupus erythematosus (SLE) who are more likely to have renal disease and a low C3 level. Using samples from 24 patients, we searched for glomerular deposits of HSP90 in renal biopsy specimens from seven patients with lupus nephritis and 17 cases of glomerulonephritis from patients without SLE. Positive glomerular immunofluorescent staining for HSP90 was observed in six of seven cases of SLE and positive tubular staining in two of seven SLE patients. The staining for HSP90 was granular in nature and was located in subepithelial, subendothelial and mesangial areas. None of the non-SLE renal biopsies revealed positive staining for HSP90 deposition. Further we showed the presence of anti-HSP90 IgG autoantibodies in IgG from sera of patients with SLE as well as in normal human IgG (IVIg). In normal IgG this autoreactivity could be adsorbed almost completely on F(ab')2 fragments from the same IgG preparation, coupled to Sepharose and could be inhibited by the effluent obtained after subjecting normal IgG to HSP90 affinity column. These findings indicate that anti-HSP90 natural autoantibodies are blocked by idiotypic interactions within the IgG repertoire. Unlike natural autoantibodies, anti-HSP90 IgG from SLE patients' sera were only moderately adsorbed on F(ab')2 fragments of normal IgG. These results demonstrate that immunopathogenesis of lupus nephritis is associated with HSP90 (as an autoantigen) and that the pathology is associated with altered idiotypic regulation of the anti-HSP90 IgG autoantibodies.

Immunocytochemical localization of atrial natriuretic factor (ANF) in rat female reproductive tract: evidence for a potential hormonal regulation

In the present studies atrial natriuretic factor (ANF) was characterized immunocytochemically in the reproductive tract of immature female rats, and changes of ANF levels in response to different hormonal conditions were demonstrated. Administration of pregnant mare serum gonadotropin (PMSG) to immature animals has shown to be a useful method to synchronize growth, differentiation and atresia of ovarian follicles. ANF immunoreactivity was investigated in rat uterus and oviduct during follicular growth and estrogenic dominance (48 h after PMSG treatment) and during follicular atresia and progesterone dominance (96 h after PMSG treatment). Our immunocytochemical results showed that in rat uterus ANF was localized in endometrial mucosal and glandular epithelium and smooth muscle cells of the myometrium. In the oviduct ANF immunoreactivity was observed in mucosal cells and muscle layers. Immunocytochemical staining patterns and Western blot analysis revealed that ANF levels in rat uterus and oviduct are modulated by the hormonal status. ANF immunoreactivity was elevated during estrogenic dominance (48 h after PMSG) in uterus and oviduct. However, during progesterone dominance (96 h after PMSG) elevation of ANF immunoreactivity was observed in the uterus only. These results raise the possibility that ANF expression in rat oviduct is positively controlled by estrogen and negatively by progesterone. ANF staining in uterus during progesterone phase provides evidence that both estrogen and progesterone regulate ANF levels in uterus. The observed staining patterns indicate that ANF may have intracellular functions as well as a role in priming the extracellular environment. Accordingly, the possibility that ANF might be an important regulatory molecule for autocrine/paracrine communication within the female reproductive tract should be considered.

Spatial and temporal distribution of atrial natriuretic factor in the rat testis

The atrial natriuretic factor (ANF) is a cardiac hormone whose gene and receptor are widely expressed in extracardiac tissues and organs. ANF induces its biological effects by binding to its specific guanylyl-cyclase-A receptor, which synthesizes the intracellular second messenger cGMP. Increasing evidences indicate that the testis shows the highest reactivity of stimulation of guanylate cyclase by ANF. The well-established functionally active ANF receptors in seminiferous tubules raise the question of the origin and function of ANF in the testis. Therefore, the current study was carried out to investigate the spatial and temporal distribution of ANF in the rat testis by use of immunocytochemistry. Our immunocytochemical results showed that at different pre- and postnatal ages of testicular development ANF was constantly expressed in Leydig cell cytoplasm. However, the intensity of immunoreaction varied between the different Leydig cell populations (fetal, progenitor and immature) and apparently depends on the acquisition of testosterone producing ability. In seminiferous tubules ANF staining was established in the cytoplasm of the developing spermatocytes, in degenerating germ cells (23-day of age) in the cytoplasm of Sertoli cells, cap phase of acrosomal development and in the spermatids (55-day of age). The observed staining patterns suggest a broader spectrum of ANF activities and a possible participation in the whole process of regulation of germ cell development. Our data provide additional support for the hypothesis that ANF plays a major role in autocrine/paracrine regulation of the rat male gonad.

Reduced concentrations of soluble adhesion molecules after antioxidant supplementation in postmenopausal women with high cardiovascular risk profiles--a randomized double-blind study

BACKGROUND

One of the suggested mechanisms of increased cardiovascular risk in postmenopause is a loss of the antioxidant effects of estrogens. It has been shown that classical cardiovascular risk factors increase oxidative stress on the arterial wall, and that endothelial cells react to this insult by increased expression of cellular adhesion molecules (CAM), which in turn are markers of arterial wall inflammation.

METHODS

A randomized, placebo-controlled, double-blind study was performed in 60 postmenopausal women with high cardiovascular risk profiles, but free from clinical atherosclerotic disease. Patients were randomized to either antioxidant supplementation (using a combination of natural antioxidants; n = 30) or placebo (n = 30), and followed for 12 weeks. The concentrations of the adhesion molecules sVCAM-1 and sICAM-1 were measured by ELISA at baseline and at the end of the study, as well as total cholesterol, LDL, HDL, triglycerides and blood pressure.

RESULTS

27 women in the antioxidant supplementation group and 29 on placebo completed the study. At baseline, there were no significant differences in measured parameters between the groups: sICAM-1 concentrations were 341.8 +/- 116.9 vs. 349.9 +/- 104.6 ng/ml (active treatment vs. placebo; p = n.s.) and sVCAM-1 concentrations were 780.5 +/- 325.8 vs. 761.0 +/- 333.7 ng/ml (p = n.s.). In contrast, at the end of the study, sICAM-1 concentrations were 301.6 +/- 56.0 vs. 356.0 +/- 134.8 ng/ml (active treatment vs. placebo; p = 0.053) and sVCAM-1 concentrations were 656.0 +/- 326.5 vs. 818.5 +/- 381.0 ng/ml (p = 0.04). There were no significant differences between or changes within the groups in measured cholesterol and blood pressure.

CONCLUSION

Antioxidant supplementation reduces serum concentrations of endothelium-derived adhesion molecules sICAM-1 and sVCAM-1 in postmenopausal women with high cardiovascular risk profiles.

Immunohistochemical detection of atrial natriuretic factor (ANF) in different ovarian cell types

OBJECTIVE

Atrial natriuretic factor (ANF) and its receptors were identified in various tissues and organs including the female reproductive system. The present studies were undertaken to investigate ANF localization in immature rat ovaries, and the changes of ANF expression in response to different ovarian hormonal conditions.

METHODS

ANF was characterized immunocytochemically during different ovarian status using an animal model with synchronized ovarian follicular growth and atresia induced by pregnant mare serum gonadotropin (PMSG). This treatment in prepubescent rats produces a series of ovarian changes mimicking follicular growth and differentiation (48 h after PMSG treatment) and atresia (96 h after PMSG treatment) and permits the synchronization of events for investigation purposes.

RESULTS

Our findings showed that in immature rat ovaries ANF was localized primarily in granulosa cells of all developing follicles (healthy and atretic). Immunocytochemical analysis revealed that during follicular growth and differentiation (48 h after PMSG) ANF was present in all steroid producing cells - interstitial, thecal and granulosa cells. ANF immunoreactivity was also detected in the cytoplasm and nuclear compartment of the growing oocytes. In all atretic follicles ANF staining was detected at 96 h after PMSG injection, but the intensity of the reaction varied with the degree of atresia, the mostly pronounced reaction being observed in the late stage of atresia.

CONCLUSIONS

These results indicate that ANF represents a unique peptide, which is expressed in different ovarian cell types and responds to different developmental programming.

Localisation of atrial natriuretic factor (ANF) in rat testis after Leydig cell destruction: evidence for a potential role in regulating gonadal function

OBJECTIVE

Since the atrial natriuretic factor (ANF) is synthesized in various peripheral tissues, where it acts in an autocrine or paracrine fashion, the aim was to gain new insight into ANF expression and function in rat testis after Leydig cell destruction (LCD).

METHODS

Leydig cell destruction was performed by the treatment with ethane dimethane sulphonate (EDS).

RESULTS

ANF was expressed after Leydig cell destruction and total elimination (24 h and 7 days after EDS treatment) and also after Leydig cell regeneration (21 and 45 days after EDS treatment). ANF staining in the interstitial compartment was observed in apoptotic Leydig cells 24 h after treatment. In seminiferous epithelium ANF labeling was detected in Sertoli and germ cell cytoplasm with a more prominent labeling in spermatids. The degenerating germ cells were totally labeled.

CONCLUSIONS

The demonstration of ANF staining in seminiferous epithelium after Leydig cells elimination and androgen deprivation suggests that Leydig cells are not the sole source of ANF in rat testis and that the seminiferous epithelium may be a new site in which ANF may be synthesized. The result indicates that ANF plays a role in regulating gonadal function.

Cross-reacting idiotypes on anti-insulin autoantibodies in autoimmune diseases, identified by monoclonal antibodies

Investigations on the specific idiotypes of autoantibodies are supposed to help with the understanding of the control mechanisms participating in the pathogenesis of autoimmune diseases. This study describes three monoclonal antibodies (Mabs) that recognize distinct idiotypic determinants on anti-insulin autoantibodies. The preabsorption by IAA-positive sera of insulin inhibits their subsequent binding to the anti-Id, thus suggesting that the Mabs recognize epitopes located at or near the binding site of insulin autoantibodies (IAA). These idiotypes are detected in sera from patients with insulin-dependent diabetes mellitus (IDDM), which are IAA-negative, also. It is possible that the expression of the idiotypes recognized might generally be associated with induction of autoantibodies, since they were found in sera from patients with rheumatoid arthritis (RA), autoimmune thyroid disease (AITD), and cataract (K). It can be assumed that the corresponding idiotypes of these Mabs, or similar structures (sequential or conformational), are expressed on autoantibodies with various antigen-binding specificities. These data suggest that some autoimmune diseases are preceded by the secretion of autoantibodies which express a common or similar pathological idiotype.

Selective effect of methoxyindoles on the lymphocyte proliferation and melatonin binding to activated human lymphoid cells

Three pineal methoxyindoles (melatonin (Mel), 5-methoxytryptamine (5-MTA) and 5-methoxytryptophol (5-MTO)) were studied for their ability to influence the proliferative response of human peripheral blood lymphocytes (PBL) and tonsillar lymphocytes (TL) following activation with concanavalin A (ConA) in vitro. The ConA-stimulated DNA synthesis was affected in a different dose-dependent mode by the methoxyindoles tested. Melatonin and 5-MTO inhibited and 5-MTA increased the ConA-induced [3H]thymidine incorporation in PBL and TL. The initial screening for 2-[125I]iodomelatonin binding using a single point assay revealed significantly increased specific binding to PBL and TL after 72-h stimulation with ConA as compared to the non-activated cell cultures. Coincubation of separate lymphocyte cultures with ConA and Mel or 5-MTO resulted in inhibition of the specific 2-[125I]iodomelatonin binding (85% and 74%, respectively). The specific binding determined in the presence of 5-MTA did not differ from control values. Series of saturation and competition experiments were performed to examine the binding characteristics of ConA-stimulated lymphocytes for 2-[125I]iodomelatonin. The radioligand labelled binding sites of high affinity (Kd = 0.14 +/- 0.03 nM) and low capacity (Bmax = 6.8 +/- 1.5 fM/mg protein). Competitive studies with a variety of indoles determined the following order of relative potency for inhibition of 2-[125I]iodomelatonin binding in TL: 2-iodomelatonin > melatonin > > 5-methoxytryptophol. 5-Methoxytryptamine did not show displacement potency for the labelled ligand. Collectively, our data suggest that pineal hormones might be directly involved in the regulation of the T-lymphoproliferative response of human lymphoid cells. We show the availability of melatonin receptors, which seem to be an intrinsic characteristic of activated human lymphocyte populations. While the effects of Mel and 5-MTO can be linked to the binding sites described, it is unlikely that serotonin agonists like 5-MTA may act through the same sites to influence the mitogen-stimulated lymphocyte proliferation.

Syngeneic anti-idiotypic monoclonal antibodies against an anti-human chorionic gonadotrophin antibody

Monoclonal antibody designated 1B10 (Mab 1B10) has been shown to be highly specific for the beta-chain of human chorionic gonadotrophin (HCG). We used this antibody to investigate its paratope using anti-idiotypic antibodies. Purified Mab 1B10 has been used to immunize syngeneic BALB/c mice to produce anti-idiotypic monoclonal antibodies. An enzyme immunoassay (ELISA) on Mab 1B10 coated plate was employed to screen the supernatants of growing hybridomas. The specificity of each antibody selected was assessed using an inhibition ELISA and immunoblotting. Monoclonal antibodies belonging to two categories were selected. (a) Those (designated Mab 4F8 and Mab 7G9) recognizing epitopes of the Ig molecule located in/or near the antigen-binding site of Mab 1B10. In ELISA these antibodies were shown to inhibit in a dose-dependent manner, the reaction of Mab 1B10 with its specific antigen; (b) those (Mab 2B8, Mab 3B8) reacting with epitopes located outside of the antigen binding site of the antiHCG antibody molecule and did not influence the reactions of Mab 1B10 and its antigen. Following immunization of syngeneic BALB/c mice monoclonal antibodies (Mab 4F8, Mab 7G9) were produced which recognized epitopes located on the variable region of Mab 1B10 since they did not react with other murine monoclonal antibodies of the same isotype. These antibodies inhibited the binding of Mab 1B10 to its corresponding epitope on the molecule of HCG and they can be defined as syngeneic anti-idiotypic antibodies.

Human hybridomas secreting monoclonal antitreponemal antibodies raised after in vitro stimulation of human lymphocytes

Peripheral blood lymphocytes from patients with syphilis were stimulated in vitro against Treponema pallidum extract and consequently were fused with mouse myeloma cells to raise heterohybridomas secreting specific human antibodies. In these experiments, 5 heterohybridomas were selected which were shown to secrete monoclonal antibodies which recognized treponemal antigens. Some of the monoclonal (Mab 1C12, Mab 1D11) react with antigens specific to T. pallidum while others (Mab 2A2, Mab 2C8, Mab 2C11) bind to treponemal components which demonstrated group specificity.

Purification and characterization of sperm-coating antigen, identified by a monoclonal antibody

A procedure was designed for purification of a human seminal plasma-specific antigen (HSP-antigen) identified by a monoclonal antibody produced in this laboratory (mAb 4E6). Pooled human seminal plasma was fractionated by consecutively applied methods: affinity chromatography on Lentil lectin sepharose, gel chromatography on Ultrogel AcA 34 and immunoaffinity on mAb 4E6 coupled CNBr-Sepharose 4B. The antigen-containing fraction obtained after this procedure was proved to be homogeneous when analysed by electrophoresis in polyacrylamide gel. After the consecutive purification procedures the degree of purification was 128 times as compared to the starting material. Electrophoretic analysis of the purified 4E6 antigen under reducing conditions showed that it consisted of 3 polypeptide subunits with molecular weight 70 kDa, 64 kDa and 60 kDa respectively. On the basis of the data obtained from competitive ELISA testing of sera from infertile patients it has been suggested that the identified antigen may be involved in pathogenesis of immunologic infertility.

An anti-digoxin monoclonal antibody seems to express more than one functional paratope

An anti-digoxin monoclonal antibody (mAb 4G3) has been produced and characterized with respect to its fine specificity and affinity. In an independent series of experiments anti-idiotypic monoclonal antibody (mAb 7G9) was selected which reacted with the antigen-binding center of an anti-human chorionic gonadotropin monoclonal antibody (anti-hCG mAb 1B10). In detailed studies on its binding characteristics it has been shown that mAb 4G3 binds to an anti-idiotypic monoclonal antibody mAb 7G9 in solution. Western blotting experiments showed that mAb 4G3 reacted against antiidiotypic antibody under non-reducing conditions, only. Moreover, mAb 4G3 has been shown to express self-binding properties. Absorption with saturating amounts of its specific hapten, i.e. digoxin, did not change the binding of mAb 4G3 to anti-idiotypic antibody and its self-binding ability. It is speculated on the basis of these data that mAb 4G3 possesses more than one functional paratope.

Conformation-sensitive immunoassay: optimisation, validation and evaluation

A conformation-sensitive immunoassay (CSI) has recently been developed (Pfund and Bourdage, 1990). This paper describes the optimal laboratory protocol which makes this method useful as an early screening procedure for conformation-sensitive monoclonal antibodies. The method was validated with a panel of 12 monoclonal antibodies. Results from our experiments confirm that this variant of CSI can be applied in the analysis of purified proteins and glycoproteins, as well as complex mixtures of antigens.

Identification and characterization of human acrosomal antigen defined by a monoclonal antibody with blocking effect on in vitro fertilization

A monoclonal anti-human sperm antibody (Mab 1A1) has been produced by fusion of myeloma cells with splenocytes from a BALB/c mouse immunized with in vitro capacitated human spermatozoa. Immunofluorescence studies with Mab 1A1 show that it recognizes an antigen(s) (Ag 1A1) which is located in the acrosome of human spermatozoa. As shown by Western blotting experiments, 1A1 antigen represents a family of proteins with Mr ranging from 20 kDa to 34 kDa. Immunofluorescence observations on epitope exposure and location suggest that during in vitro capacitation of human spermatozoa, Mab 1A1 epitope-bearing molecules are concentrated in regularly arranged granules in the acrosome. After long-term incubation the epitope is exposed on the apical acrosome surface exhibiting a spot-like arrangement. The 1A1 epitope is widely distributed among mammalian species: boar, ram, mouse and rat acrosome is intensively stained by Mab 1A1. The antibody inhibits in vitro fertilization mainly by blocking sperm attachment to and penetration through the zona pellucida when included in the medium for the in vitro fertilization of mouse, porcine and human oocytes.

Antigenic differences between Trichinella spiralis and T. pseudospiralis detected by monoclonal antibodies

Antigenic differences between Trichinella spiralis and T. pseudospiralis were established using two monoclonal antibodies (mAbs) that show different specificities to muscle larvae of the two variants. Enzyme-linked immunosorbent assay (ELISA) revealed that mAb 3G6 reacts positively against T. spiralis, T. nelsoni, T. nativa and T. pseudospiralis, whereas mAb 3E10 does not react with T. pseudospiralis under the same experimental conditions. These antigenic differences were confirmed after preabsorption of the antibodies with serial dilutions of extracts of T. spiralis or T. pseudospiralis muscle larvae. The indirect immunofluorescence technique showed that the antigen corresponding to mAb 3G6 is located in the stichosomes and the cuticle surface of both T. spiralis and T. pseudospiralis. In contrast, mAb 3E10 positively stained cryostat sections of T. spiralis, forming a dense reaction product on the surface of the whole larvae and the surrounding capsule. This antibody can be quite useful as a specific probe for distinguishing T. spiralis from T. pseudospiralis in taxonomic studies. Using an avidin-biotin system, we could prove that mAb 3G6 recognizes an excretory/secretory-type antigen.

Characterization of NAD(P)H diaphorase from boar spermatozoa using specific monoclonal antibodies

1. After immunization of BALB/c mouse, four monoclonal antibodies against soluble NADH diaphorase from ejaculated boar spermatozoa were produced and characterized. The monoclonal antibodies were designated as follows Mab 1F2, Mab 4E2, Mab 5B8, Mab 5D8. 2. These monoclonal antibodies react with other enzyme forms-sedimentary NADH and NADPH and soluble NADPH and inhibit (although not completely) their activity. It is supposed that different forms of the enzyme share some common epitopes. 3. Treatment of ejaculated boar semen with 2O-methylcholanthrene causes an increase of the activity of the soluble diaphorase form only. 4. These results lead to the assumption that the sperm diaphorase is a dynamic enzyme system consisting of four immunologically similar isoenzymes although their functions are different.

Demonstration of a phase (stage)-specific embryonic brain antigen in human meningioma

The water-soluble antigens of human embryonic brain were studied using a rabbit antiserum to human 8- to 10-week embryonic brain (non-absorbed and absorbed with extracts of human embryonic and adult organs). A phase (stage)-specific brain antigen(s) characteristic for the human 8- to 10-week-old embryo was detected by double immunodiffusion and immunoelectrophoresis in agarose gel. The testing of this anti-embryonic brain serum against saline extracts of human brain tumours (meningiomas, glioblastomas, astrocytomas, neurinomas and brain metastasis of carcinoma) revealed the presence of an "embryonic" antigen in the human meningioma only. Immunochemically this meningioma-associated antigen is identical to a phase (stage)-specific antigen of the 8- to 10-week embryo.