Generation and characterization of a polyclonal antipeptide antibody to human glycodelin

Expression level of TNF-α in decidual tissue and peripheral blood of patients with recurrent spontaneous abortion

Objective

This study aimed to determine the express level of tumour necrosis factor α (TNF-α) in the decidual tissue and peripheral blood of patients with recurrent spontaneous abortion (RSA).

Material and methods

Eighty RSA patients and 100 control women were recruited in this study. Enzyme-linked immunosorbent assay (ELISA) was applied to determine the expression level of TNF-α in peripheral blood and decidual tissues from both groups. Additionally, the expression level of TNF-α was compared between RSA patients with different numbers of abortions, as well as primary and secondary RSA patients.

Results

The expression level of TNF-α in peripheral blood and decidual tissues of RSA patients was significantly higher compared to the controls (p < 0.001). Patients who had undergone RSA twice expressed TNF-α in peripheral blood and decidual tissues at a similar level to patients who had experienced RSA three times (p > 0.05), but significantly lower than patients who had experienced RSA more than three times (p < 0.001). The expression level of TNF-α in peripheral blood and decidual tissues was significantly higher in the secondary RSA patients, when compared with primary RSA patients (p < 0.001).

Conclusions

Taken together, the relatively high expression level of TNF-α in decidual tissue and peripheral blood may be one of the causes of RSA and therefore could be used as a clinical indicator.

Affinity purification of native glycodelin from amniotic fluid for biological investigations and development of a glycodelin ELISA for clinical studies

INTRODUCTION

Glycodelin is a glycoprotein with different oligosaccharides that are responsible for its diverse biological functions in contraception and immunosuppression. Therefore, it is necessary to have access to adequate amounts of glycodelin with retained carbohydrate structure for functional studies because the carbohydrate part can be lacking or be insufficient in recombinant glycodelin from prokaryotic and eukaryotic cell systems.

METHODS AND RESULTS

Native glycodelin was purified from amniotic fluid by a series of affinity chromatography steps and had many glycosylated forms verified by mass spectrometry. About 7.5 mg glycodelin was obtained from 1.5 L amniotic fluid. No high molecular mass forms of glycodelin were found in amniotic fluid. Aliquots of the purified glycodelin were used as an immunogen in rabbits for antibody production against glycodelin and a calibrator in a highly sensitive glycodelin enzyme-linked immunosorbent assay (ELISA) with a detection limit of about 1 μg/L.

CONCLUSIONS

Native glycodelin was purified from amniotic fluid and used as an immunogen for raising a rabbit antibody against glycodelin and a calibrator in a highly sensitive glycodelin ELISA. We found no high molecular mass forms of glycodelin in amniotic fluid. Aliquots of the purified glycodelin were set aside for functional studies which are in progress.

Interaction of Mycoplasma genitalium with host cells: evidence for nuclear localization

Mycoplasma genitalium (Mg) is a mollicute that causes a range of human urogenital infections. A hallmark of these bacteria is their ability to establish chronic infections that can persist despite completion of appropriate antibiotic therapies and intact and functional immune systems. Intimate adherence and surface colonization of mycoplasmas to host cells are important pathogenic features. However, their facultative intracellular nature is poorly understood, partly due to difficulties in developing and standardizing cellular interaction model systems. Here, we characterize growth and invasion properties of two Mg strains (G37 and 1019V). Mg G37 is a high-passage laboratory strain, while Mg 1019V is a low-passage isolate recovered from the cervix. The two strains diverge partially in gene sequences for adherence-related proteins and exhibit subtle variations in their axenic growth. However, with both strains and consistent with our previous studies, a subset of adherent Mg organisms invade host cells and exhibit perinuclear targeting. Remarkably, intranuclear localization of Mg proteins is observed, which occurred as early as 30 min after infection. Mg strains deficient in adherence were markedly reduced in their ability to invade and associate with perinuclear and nuclear sites.

Immunohistochemistry, glycosylation and immunosuppression of glycodelin in human ovarian cancer

Glycodelins (Gds) are glycoproteins with a gender specific glycosylation. Glycodelin A (GdA) is primarily produced in endometrial and decidual tissue and secreted to amniotic fluid. Glycodelins were also identified in several cancer types, including serous ovarian cancer. Gds act as a T-cell inhibitor and are involved in inactivation of human monocytes. With a Gd peptide antibody, derived from a 15 amino acid sequence of human Gd and in situ hybridization experiments, the expression of Gd in serous, mucinous, endometrioid and clear cell ovarian tumors was identified. In contrast to former investigations with antibodies against GdA, a positive immunohistochemical reaction for Gd was observed in all forms of epithelium ovarian cancer. These results were confirmed with in situ hybridization. In addition, Gd is expressed in granulose cell tumors, a non-epithelial form of ovarian cancer. Furthermore, Gd was purified from ascites fluid of ovarian cancer patients. Ascites Gd showed significant differences in its structure of sialyl Lewis-type oligosaccharides compared to GdA. Additionally, ascites Gd inhibits IL-2 stimulated proliferation of peripheral blood leucocytes and inhibits adhesion of SLe(X)-positive cells to E-selectin. Therefore, Gd could act as an inhibitor of lymphocyte activation and/or adhesion in ovarian cancer.

Glycodelin gene expression in human peripheral white blood cells

BACKGROUND

Glycodelin plays an important role in normal and abnormal reproductive growth. The in vitro properties of glycodelin have been studied in K562 cells. The role of glycodelin in vivo in the peripheral circulation has not been determined.

AIM

To determine if circulating leukocytes in normal subjects express the glycodelin gene, with a view to understanding its contribution to various disease processes.

METHOD

RT-PCR analysis of mononuclear cells isolated from the blood of healthy volunteers was used to show glycodelin mRNA expression. Immunocytostaining was performed using anti-glycodelin antibody.

RESULTS

PCR analysis illustrated the expression of the glycodelin gene in peripheral mononuclear cells. Glycodelin protein in these cells was confirmed with immunostaining.

CONCLUSION

The presence of glycodelin in peripheral white blood cells was demonstrated. The ability of glycodelin to stimulate angiogenesis and act as an immunosuppressive agent could be an indicator of the role of peripheral leukocytes in various disease states.

Glycosylation related actions of glycodelin: gamete, cumulus cell, immune cell and clinical associations

Glycodelin is an example of a glycoprotein whose complex-type glycans mediate biological actions in human reproduction and immune reactions. Being attached to an identical protein backbone, glycodelin oligosaccharides vary significantly from one reproductive tissue to another and have an effect on its own secretion and role in cell communication. For instance, uterine glycodelin-A inhibits sperm-oocyte interaction by binding on the sperm head. This is a glycosylation-dependent phenomenon, in which fucosyltransferase-5 plays a key role. Glycodelin-S from seminal plasma binds evenly around the sperm head and maintains an uncapacitated state in the spermatozoa, until the isoform is detached during sperm passage through the cervix. Glycodelin-F from follicular fluid and Fallopian tube binds to the acrosomal region of the sperm head, thereby inhibiting both the sperm-oocyte binding and premature progesterone-induced acrosome reaction. The cumulus cells surrounding the oocyte can capture glycodelin-A and -F from the surrounding environment and convert these isoforms to a cumulus cell isoform, glycodelin-C. It differs by glycosylation from the other isoforms, and it too attaches on the sperm head, with the highest density in the equatorial region. Glycodelin-C is capable of detaching the sperm-bound inhibitory isoforms so that the sperm-oocyte binding is enhanced. Glycodelin-A also has immunosuppressive actions directed to cellular, humoral and innate immunity. Although these actions depend mainly on the protein backbone, glycosylation also plays a part. Glycosylated glycodelin may be involved in the protection of spermatozoa against maternal immune reactions, and glycodelin also has apoptogenic activity. Some glycosylation patterns of glycodelin may mask its apoptogenic domain. This review updates the recent research and clinical associations of glycodelin, highlighting the role of glycosylation.

Glycodelin mediates the increase in vascular endothelial growth factor in response to oxidative stress in the endometrium

OBJECTIVE

We hypothesized that glycodelin stimulates vascular endothelial growth factor (VEGF) expression in response to oxidative stress.

STUDY DESIGN

EM42 (human endometrial epithelial cell line) and primary endometrial epithelial cells were subjected to oxidative stress with minimally oxidized low density lipoprotein (mLDL). Cells were also incubated with no LDL (control) or native LDL (nLDL). Each condition was incubated with and without glycodelin antibody. Glycodelin and VEGF protein and messenger RNA (mRNA) levels were analyzed. Primary cells were cultured with glycodelin peptide to evaluate the effect on VEGF protein and mRNA.

RESULTS

Glycodelin and VEGF protein and mRNA were higher for cells grown with mLDL (P < .05), while glycodelin antibody attenuated the increase in VEGF protein (P < .01). Glycodelin peptide increased VEGF mRNA and protein (P < .05).

CONCLUSION

Glycodelin may act as an autocrine factor within endometriotic implants to increase VEGF expression during oxidative stress.

Glycodelin A is expressed differentially in normal human endometrial tissue throughout the menstrual cycle as assessed by immunohistochemistry and in situ hybridization

OBJECTIVE

To [1] evaluate glycodelin A immunolabeling in normal endometrium with specific monoclonal (mAb) and polyclonal peptide (pAb) antibodies, [2] to assess glycodelin messenger RNA (mRNA) by in situ hybridization, and [3] to conduct deglycosylation experiments to evaluate the recognized epitope of the mAb vs. pAb.

DESIGN

Retrospective immunohistochemical analysis.

SETTING

University institute and hospital in Germany.

PATIENT(S)

Normal human endometrial tissue from the proliferative (PP), early secretory, and late secretory phases were obtained from patients undergoing surgery for benign diseases.

INTERVENTION(S)

Generation of a pAb in rabbit, immunohistochemistry, and in situ hybridization.

MAIN OUTCOME MEASURE(S)

Semiquantitative and computerized analysis.

RESULT(S)

A statistically significant increase of the glycodelin A immunolabeling in the late secretory phase compared with PP was demonstrated by using the mAb. Polyclonal-peptide antibody immunolabeling also showed a rise between the PP and late secretory phases, but without statistical significance. In situ hybridization demonstrated a statistically significantly higher mRNA content during the early secretory phase compared with during PP.

CONCLUSION(S)

Glycodelin was demonstrated in normal endometrium at the protein and mRNA levels. The mAb may be more useful in assessing glycodelin expression in endometrium, because it probably can bind to glycodelin A-unique glycan structures, in contrast to the peptide pAb. This is of major interest because it may reveal possible structural and functional relationships in different parts of this molecule and elucidate possible functions of this glycoprotein in human endometrial tissue.

Development and characterization of monoclonal antibodies for the immunohistochemical detection of glycodelin A in decidual, endometrial and gynaecological tumour tissues

AIMS

Glycodelin is a glycoprotein with a molecular weight of 28 kDa. Unusual LacdiNAc structures have been identified on glycodelin A, isolated from amniotic fluid. Three major functions of this glycoprotein have been identified. Glycodelin is an immunosuppressive molecule, a marker of morphological differentiation, and a contraceptive. Because no monoclonal antibodies for glycodelin A are commercially available, our aim was to develop and characterize three monoclonal antibodies against this glycoprotein.

METHODS AND RESULTS

Glycodelin A was purified from amniotic fluid by three chromatographic steps and its purity was checked by SDS-PAGE. Antibodies were generated from immunized BALB/c mice. Three IgG1 monoclonal antibodies detecting glycodelin A were cloned. All three antibodies recognized carbohydrate structures of glycodelin A and did not cross-react with glycodelin S. They are applicable to immunohistochemistry (frozen and paraffin sections), ELISA and Western blots.

CONCLUSION

The new antibodies can be used for the detection of glycodelin A in frozen and paraffin-embedded decidual and endometrial tissue. One antibody (A87-B/D2) can be used for the detection of glycodelin in endometrial and ovarian tumour tissues. Because glycodelin A is a major secretory endometrial product during the luteal phase, in early pregnancy and in gynaecological tumours, the new antibodies are, potentially, valuable tools for the study of endometrial development and tumour progression.

Immunolocalization of glycodelin in the genital tract of rats

Glycodelin, also known as placental protein 14 has been predominantly localized to organs of the human genital tract. Unfortunately the physiological role of glycodelin is largely unknown since it depends on limited availability of tissues. Therefore, a suitable animal model to study the role of glycodelin would be desirable. Previously, it was shown that glycodelin mRNA is expressed in the genital tract of male and female rats. In the present study, we demonstrate the expression of glycodelin protein in male and female rats by immunohistochemistry and Western blot analysis. For this purpose a polyclonal antibody was generated against glycodelin peptide. In female rats, glycodelin was found in the epithelial gland cells of the uterus, epithelial cells of the fallopian tube as well as in corpora lutea, interstitial and theca cells of the ovary. Glycodelin was distributed in all epithelial cells of the epididymis and the seminal vesicle. In the seminiferous epithelium, glycodelin was seen in all developmental stages of spermatogonia and spermatocytes and in Sertoli cells. Whereas in the rat male reproductive tract glycodelin expression is slightly different from human or primate tissues, in organs of the rat female genital tract glycodelin expression is similar to humans and primates.

An update in recurrent spontaneous abortion

Recurrent spontaneous abortion (RSA) is defined as three or more consecutive pregnancy losses prior to the 20th week of gestation. The etiology of recurrent spontaneous abortion is often unclear and may be multifactorial, with much controversy regarding diagnosis and treatment. Reasonably accepted etiologic causes include, genetics, anatomical, endocrine, placental anomalies, hormonal problems, infection, smoking and alcohol consumption, exposure to environmental factors, psychological trauma and stressful life event, certain coagulation and immunoregulatory protein defects. Detection of an abnormality in any of these areas may result into specific therapeutic measures, with varying degrees of success. However, the majority of cases of RSA remains unexplained and is found to be associated with certain autoimmune (APA, ANA, ACA, ATA, AECA) and alloimmune (APCA, Ab2, MLR-Bf) antibodies that may play major role in the immunologic failure of pregnancy and may lead to abortion. Alteration in the expression of HLA-G molecules, T-helper-1 (Th-1) pattern of cytokines and natural killer (NK) cells activity may also induce abortion. Various forms of treatment like antithrombotic therapies such as aspirin and heparin, intravenous immunoglobulin (IVIg) therapy, immunotherapy with paternal lymphocytes and vitamin D3 therapy are effective mode of treatment for unexplained cause of fetal loss in women with RSA.

Oxidants and antioxidants affect the expression of glycodelin

Glycodelin is a glycoprotein that has immunosuppressive activity. We have shown that K562 cells, hematopoitic progenitor cells, are capable of synthesizing glycodelin peptide (Gp) and, perhaps, contribute to Gp in tissues. In addition, several reproductive and nonreproductive tissues themselves are capable of synthesis of glycodelin. In this study, we report that lipid peroxides induce the synthesis of Gp. Antioxidants vitamin E and pyrrolidine dithiocarbamate (PDTC) and antioxidizing enzymes catalase and superoxide dismutase (SOD) effectively blocked phorbol myristate acetate- (PMA-) and lyso phosphatidic acid- (LPA-) induced synthesis of Gp. Dioctanoin (a mimic of diacylglycerol) activated Gp synthesis, and an inhibitor of protein kinase C (PKC) downregulated the response. Based on these observations, we postulate that oxidants by way of PKC might potentiate the angiogenic process.

Glycodelin: a major lipocalin protein of the reproductive axis with diverse actions in cell recognition and differentiation

Glycodelin is a glycoprotein that belongs to the lipocalin superfamily. Depending on glycosylation, glycodelin appears in various isoforms. In the uterus, glycodelin-A is the major progesterone-regulated glycoprotein secreted into uterine luminal cavity by secretory/decidualized endometrial glands. The other tissues expressing glycodelin include fallopian tubes, ovary, breast, seminal vesicle, bone marrow, and eccrine glands. Glycodelin-A potently and dose-dependently inhibits human sperm-egg binding, whereas differently glycosylated glycodelin-S from seminal plasma has no such effect. Absence of contraceptive glycodelin-A in the uterus during periovulatory midcycle is consistent with an open "fertile window." Glycodelin induced by local or systemic administration of progestogens may potentially reduce the fertilizing capacity of sperm in any phase of the menstrual cycle. Glycodelin also has immunosuppressive activity. Its high concentration at the fetomaternal interface may contribute to protection of the embryonic semiallograft. Besides being an epithelial differentiation marker, glycodelin appears to play a role in glandular morphogenesis, as transfection of glycodelin cDNA into a glycodelin-negative breast cancer cells resulted in formation of gland-like structures, restricted proliferation, and induction of other epithelial markers. These various properties, as well as the chemistry, biology, and clinical aspects of glycodelin, continue to be areas of active investigation reviewed in this communication.

Lysophosphatidic acid induces glycodelin gene expression in cancer cells

Glycodelin is a glycoprotein that has been suggested to be important in normal pregnancy and in malignancy. The regulation of its synthesis has not been studied. In this study, we report the induction of glycodelin gene expression by lysophosphatidic acid (LPA). We studied the effect of LPA (5, 10 and 25 microM) on glycodelin production in breast (MDA-MB-231), cervical (Hela), endometrial (RL-95), ovarian cancer (OVCAR-3) and erythroleukemia (K562) cells. There was a dose-dependent (5-25 microM) induction of glycodelin gene and protein expression in these cell types. LPA is a mimic of phorbol myristate acetate (PMA) action and is found to be elevated in high concentrations in the serum of cancer subjects. As glycodelin is an angiogenic protein with a potential immunosuppressive role, control of LPA synthesis might offer a potential target for intervention.

Angiogenic role for glycodelin in tumorigenesis

Angiogenesis plays an important role in neovascularization in tumors. Glycodelin, a hormone-responsive protein, has been detected in tumors of reproductive organs and is found in high levels in the plasma of subjects with gynecological malignancies. Glycodelin is also found in the endothelial cells of the umbilical cord and in the blood vessels of tumors. In this study, we tested whether glycodelin-rich amniotic fluid and a synthetic peptide derived from the sequence of glycodelin peptide (Gp) might promote angiogenic response by examining the migration and tube formation in human umbilical cord vein endothelial cells (HUVECs). Increased migration and tube formation of HUVECs were found in the presence of amniotic fluid and Gp, and this increase was blocked by antibody to Gp and by an anti-vascular endothelial growth factor (VEGF) antibody, suggesting that the angiogenic effects of glycodelin might be mediated by VEGF. The results also showed that Gp significantly increased the release of VEGF protein and mRNA expression in HUVECs, RL-95 (human endometrial carcinoma cells), OVCAR-3 (human ovarian adenocarcinoma cells), EM42 (human endometrial epithelial cells), THP-1 (human monocyte), and MCF-7 and MDA-MB-231 (human breast adenocarcinoma cells) cell lines. VEGF receptor Fit-1 mRNA expression in HUVECs was also increased in the presence of Gp. These findings, together with the suggestion from the literature that glycodelin may have immunosuppressive properties, suggest that glycodelin might play an important role in neovascularization during embryogenesis and tumor development.

Increased glycodelin levels in gynecological malignancies

Glycodelin, an immunosuppressive protein with contraceptive properties, is synthesized by a variety of tissues and cell types. The ability of reproductive tissues to synthesize glycodelin is of major interest in pregnancy and disease conditions. We studied glycodelin levels in subjects with malignant gynecological tumors and in control subjects. Using a polyclonal glycodelin antibody against the synthetic glycodelin peptide sequence, an enzyme-linked immunosorbent assay (ELISA) was devised to measure plasma glycodelin levels. The assay detected as much as 5 ng/ml of glycodelin. There was a significant increase in plasma glycodelin levels in endometrial > ovarian > cervical cancer subjects when compared to those of controls. Strong expression of mRNA and protein were found in the ovarian and endometrial tumor tissues. Given glycodelin's immunosuppressive abilities, increased level of glycodelin may facilitate tumor growth in gynecological malignancies.

Retinoic acid suppresses interleukin-6 production in human endometrial cells

OBJECTIVE

To determine whether retinoic acid (RA) can regulate the expression of interleukin (IL)-6 in human endometrial cells in a manner that might be beneficial to women with endometriosis.

DESIGN

In vitro study.

SETTING

Academic medical center.

PATIENT(S)

Patients with endometriosis and controls.

INTERVENTION(S)

Endometrial cell cultures were treated with RA.

MAIN OUTCOME MEASURE(S)

Interleukin-6 protein secretion, messenger RNA expression, and IL-6-promoter activity.

RESULT(S)

Using a human endometrial cell line (EM42), as well as primary stromal and epithelial endometrial cells, we demonstrated that RA suppresses IL-6 protein and messenger RNA expression in a time- and dose-dependent fashion, showing maximal effects at pharmacologically achievable blood serum concentrations (micromoles per liter). Retinoic acid specifically inhibited the activity of IL-6-promoter reporter constructs that were transiently transfected into EM42 cells. Mutational analysis of reporter constructs indicated that RA suppression of IL-6 expression was mediated, at least in part, through the nuclear factor IL-6 binding site located in the IL-6 promoter.

CONCLUSION

Retinoids may play a fundamental role in altering the pathophysiology of endometriosis related to aberrant production of IL-6.

Implications in the maintenance of pregnancy: I. Presence of immunoreactive glycodelin in human umbilical cord vein endothelial cells

OBJECTIVE

We previously reported an antipeptide antibody to human glycodelin that recognizes glycodelin in amniotic fluid and epithelial glands of the endometrium. The objective of this study was to determine the presence of glycodelin in human umbilical cord.

DESIGN

Controlled clinical study.

SETTING

Healthy women undergoing normal delivery at Grady Memorial Hospital, Atlanta, Georgia.

PATIENT(S)

Healthy women undergoing normal delivery.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Umbilical cord vein was isolated from the cord and used for immunohistochemical studies. Human umbilical cords and placentae were collected after full-term delivery. Cords were washed and fixed with formal sucrose. Decidua tissues and blood vessels from placentae were dissected out and fixed. Cryostat sections were immunostained with anti-glycodelin peptide antibody and anti-von Willebrand factor antibody.

RESULT(S)

Endothelial cells of human umbilical cord vein and artery were strongly immunostained with antiglycodelin antibody. Endothelial cells of the vein were more strongly stained than those of the artery. These cells were confirmed as endothelial cells by positive immunostaining with anti-von Willebrand factor. The epithelial cells outlining the cord were stained with antiglycodelin antibody but not with anti-von Willebrand factor antibody.

CONCLUSION(S)

This is the first study showing that immunoreactive glycodelin is present in endothelial cells of the umbilical cord. Glycodelin in the umbilical cord may have immunosuppressive or other, unknown functions affecting the physiology or pathophysiology of pregnancy. Whether umbilical vein endothelial cells synthesize glycodelin or serve as reservoir for glycodelin is currently under investigation.

Demonstration of the presence of lipid peroxide-modified proteins in human atherosclerotic lesions using a novel lipid peroxide-modified anti-peptide antibody

Immunohistochemical demonstration of oxidation-specific epitopes using antibodies developed against oxidized low density lipoprotein (Ox-LDL), LDL modified by products of lipid peroxidation (e.g. malondialdehyde-modified LDL), and lipid peroxide-modified albumin has been considered as strong evidence for the presence of oxidatively modified proteins in atherosclerotic lesions. However, the antigens used in the development of these antibodies were derived from lipoproteins and other proteins that are constituents of both normal and atherosclerotic arteries. In order to demonstrate the unequivocal presence of oxidatively modified proteins, we have used a 15 amino acid synthetic peptide derived from the sequence of human glycodelin. Using an antibody developed against this peptide and the second antibody developed against the lipid peroxide-modified peptide, we immunostained progressive human atherosclerotic lesions. Antibody to the unmodified peptide did not react with antigenic epitopes present in mild, moderate, or severe human atherosclerotic lesions. In contrast, the antibody developed against lipid peroxide-modified peptide highly reacted with tissue samples and provided strong evidence for the presence of lipid peroxide-modified proteins. This study suggests the presence of lipid peroxide-modified proteins in the lesion and that these epitopes are derived by direct interaction of lysine residues with lipid peroxides.