The epidermal basement membrane in basal cell carcinoma: an immunohistochemical study

An immunohistochemical study of basal cell carcinomas of varying histological type, using a panel of antibodies to constituents of the epidermal basement membrane, showed marked deficiencies in the expression of the antigens identified by the antibodies LH7.2, GB3 and G71. There was no correlation between loss of immunoreactivity to these antibodies and the histological features of the tumour.

Glycans as biochemical markers of human endometrial secretory differentiation

Uterine fluid contains a mixture of glycoprotein components the quantity and composition of which vary during the menstrual cycle. Their analysis may give clues to the involvement of maternally derived components in modulating the state of the peri-implantation blastocyst and aid in assessing the differentiation of the endometrium in preparation for implantation. Endometrial epithelium also exhibits an apical glycocalyx, the composition of which varies with the state of tissue differentiation. Evidence from animal systems suggests that glycans may be involved in molecular recognition between the embryo and maternal surface at implantation. Lectins and monoclonal antibodies to glycan epitopes have been used as sensitive and specific probes to examine the carbohydrates associated with endometrial epithelium as a function of the ovarian cycle. Numerous glycan structures are detected specifically in epithelial cells. Hitherto unsuspected biosynthetic heterogeneity is present in the glands. A secretory sialokeratan sulphate epitope is described, the occurrence of which coincides with the implantation phase of the cycle.

The effects of the antiprogesterone RU486 (Mifepristone) on an endometrial secretory glycan: an immunocytochemical study

OBJECTIVE

To examine the effects of progesterone (P) receptor blockade by RU486 (Mifepristone; Roussel-Uclaf, Paris, France) on a secretory endometrial glycan recognized by monoclonal antibody D9B1.

DESIGN

Retrospective comparison of endometrial biopsies from treated and untreated women from 2 to 8 days after the luteinizing peak (LH) peak.

SETTING

Infertility clinic, Jessop Hospital for Women, Sheffield.

PATIENTS

Twenty-two normal fertile women received the RU486. A control group of 44 normal fertile women were also assessed.

INTERVENTIONS

RU486 was administered to 22 normal women during the first half of the luteal phase and an endometrial biopsy examined 3 days later.

MAIN OUTCOME MEASURES

Immunohistochemistry was used to assess the production and secretion of the D9B1 epitope.

RESULTS

When the drug was given 2 days after the LH peak, it prevented appearance of the epitope. When RU486 was administered 5 days after the LH peak, epitope already present in gland cells was subsequently secreted.

CONCLUSIONS

These data suggest that production of the sialo-oligosaccharide is P-dependent, but secretion through established intracellular pathways is P-independent.

Integrin alpha 6/beta 4 complex is located in hemidesmosomes, suggesting a major role in epidermal cell-basement membrane adhesion

The alpha 6/beta 4 complex is a member of the integrin family of adhesion receptors. It is found on a variety of epithelial cell types, but is most strongly expressed on stratified squamous epithelia. Fluorescent antibody staining of human epidermis suggests that the beta 4 subunit is strongly localized to the basal region showing a similar distribution to that of the 230-kD bullous pemphigoid antigen. The alpha 6 subunit is also strongly localized to the basal region but in addition is present over the entire surfaces of basal cells and some cells in the immediate suprabasal region. By contrast staining for beta 1, alpha 2, and alpha 3 subunits was very weak basally, but strong on all other surfaces of basal epidermal cells. These results suggest that different integrin complexes play differing roles in cell-cell and cell-matrix adhesion in the epidermis. Immunoelectron microscopy showed that the alpha 6/beta 4 complex at the basal epidermal surface is strongly localized to hemidesmosomes. This result provides the first well-characterized monoclonal antibody markers for hemidesmosomes and suggests that the alpha 6/beta 4 complex plays a major role in epidermal cell-basement membrane adhesion. We suggest that the cytoplasmic domains of these transmembrane glycoproteins may contribute to the structure of hemidesmosomal plaques. Immunoultrastructural localization of the BP antigen suggests that it may be involved in bridging between hemidesmosomal plaques and keratin intermediate filaments of the cytoskeleton.

An endometrial factor in unexplained infertility

OBJECTIVE

To study a group of women with unexplained infertility to see whether they have a defect that is intrinsic to the endometrium.

DESIGN

Evaluation of the functional response of the endometrium by examining endometrial biopsy specimens using immunohistochemical methods in a group of women with unexplained infertility and in a control group of women with normal fertility.

PATIENTS

27 Women with unexplained infertility (average age 33.2); median duration of infertility five years. A control group of 44 women with normal fertility (average age 33.8) who were requesting sterilisation or reversal of sterilisation.

SETTING

Infertility clinic, Jessop Hospital for Women, Sheffield.

INTERVENTION

Secretory phase endometrial biopsy specimens were taken, with informed consent, as an outpatient procedure.

MAIN OUTCOME MEASURES

Immunohistochemistry with monoclonal antibody D9B1, was used to assess the production and secretion of an oligosaccharide epitope produced by endometrial gland cells between two and seven days after the luteinising hormone surge. A reflected light measuring system was used to assess the amount of epitope within the gland cells, and in the gland lumen.

RESULTS

In the control group of women, mean reflected light measurements at the cell base and cell apex peaked at three and five days after the luteinising hormone surge respectively, and in the gland lumen the epitope accumulated rapidly from three days, reaching a peak at seven days. In the women with infertility the peaks of epitope at the cell base and cell apex were lower, broader, and delayed in onset, and the build up of epitope in the gland lumen was retarded. The synthesis and secretion of the epitope in the women with infertility was therefore significantly reduced and delayed, even in the presence of normal concentrations of circulating progesterone.

CONCLUSIONS

The results suggest that a primary dysfunction of the endometrium might be associated with hitherto unexplained infertility.

Abnormal expression of G71 antibody at the epidermal basement membrane in basal cell carcinoma

The antibody G71 is a murine monoclonal antibody directed against an antigen in the basement membrane zone of many human epithelia. Ultrastructurally it is located in the lamina lucida. The epitope is carried on glycoprotein components with molecular weights of 160, 125 and 115 kilodaltons. The authors examined the immunohistochemical expression of G71 antigen, using a standard indirect immunoperoxidase technique, in benign and malignant tumors derived from the epidermis. G71 staining was consistently absent or reduced around basal cell carcinomas (n = 44). In contrast, G71 was present at the basement membrane zone of squamous cell carcinomas (n = 18) and was also frequently expressed within the cytoplasm and on the cell surface of the malignant keratinocytes. The staining pattern of G71 at the basement membrane zone was essentially normal in keratoacanthomas (n = 10), solar keratoses (n = apart from foci of attenuation. In both seborrheic keratoses and intraepidermal squamous 13), seborrheic keratoses (n = 6), and intraepidermal squamous cell carcinomas (n = 8), cell carcinomas cell-surface and cytoplasmic staining were inconstant features. In conclusion, there appears to be a specific defect of G71 antigen expression in basal cell carcinomas.

Menstrual-cycle-dependent expression of keratan sulphate in human endometrium

Immunochemical methods have been used to detect and characterize two classes of polypeptide-associated keratan sulphate (KS) in epithelial secretions from human endometrium. Monoclonal antibody D9B1 binds to a hormonally regulated sialylated epitope associated with KS in a high relative molecular mass (250,000-350,000) component that bands as a doublet in SDS/PAGE. These KS chain(s) are sensitive to keratanase, endo-beta-galactosidase and N-glycanase. A second, more highly sulphated, type of KS is also present, that is resistant to all three enzymes. This can be detected using monoclonal antibody 5D4. It is present throughout the menstrual cycle and is associated principally with a component of Mr 140,000. Thus secretory KS contributes to the environment of the implanting embryo, may be used as a molecular index of endometrial function and could be important in the establishment of pregnancy.

The translaminal fibrils of the human amnion basement membrane

The organisation of extracellular matrix beneath the human amniotic epithelium was investigated in order that the co-ordinate synthesis of basal lamina and stroma by these cells could be better understood. Transmission electron microscopy of intact tissue confirmed that stromal matrix fibrils are located between the cell surface and the basal lamina, and also penetrate the lamina. The distribution of the supralaminal fibrils and their association with the lamina was further investigated by scanning electron microscopy (SEM) after removal of the overlying epithelium. Five complementary procedures were used to remove the cells from the underlying lamina. Trypsin-EDTA treatment caused the epithelial cells to retract or detach from the lamina. SDS or ammonium hydroxide was used to extract the epithelium, which was then removed by physical shearing. Transmission electron microscopy (TEM) confirmed that the lamina densa and supralaminal fibres were present after extraction by these agents. Incubation in CHAPS, a zwiterionic detergent, did not remove the epithelium but permitted exposure of the basal lamina by mechanical scoring. Extraction with boric acid followed by osmium tetroxide produced epithelial disruption and revealed the lamina and stroma in different areas. Although the extraction pattern was different in each case, all of the five methods confirmed that individual fibrils and fibril bundles are present on the apical surface of, and enter, the lamina densa. Examination of the stromal surface of the basal lamina after fracture revealed fibrils passing from the stroma into the lamina densa. We therefore suggest that, in this tissue, newly synthesised stromal matrix components appear in an assembled fibrillar form between the basal cell surface and the basal lamina before becoming associated with the sublaminal stroma.

Attempts to identify trophoblast in peripheral blood during pregnancy using monoclonal antibody H315

In view of its potential importance in antenatal diagnosis of genetic disease, we have used flow cytometry to attempt to enumerate trophoblast cells in the peripheral blood of pregnant females. As a trophoblast marker we have used the monoclonal antibody (MAB) H315, which reacts with placental-type alkaline phosphatase (PLAP) associated with the cell-membrane of the syncytiotrophoblast. We analyzed blood leucocytes from 62 pregnant females between 6 and 22 weeks' gestation, 26 nonpregnant females, and 21 males. Overall, we detected more H315+ cells in pregnant than in nonpregnant female blood but, because of the wide variation in both groups, we found no statistically significant difference between them. We were unable to detect H315+ cells in 25% of pregnant females within the resolution of the technique. There was, in contrast, a significant difference between the number of H315+ cells in pregnant females and males. Because we were unable to demonstrate other trophoblast markers on H315+ cells isolated from maternal peripheral blood, the origin of these cells is unclear. This implies that these cells may be an unsuitable source of material for antenatal diagnosis.

The effect of the intrauterine contraceptive device on endometrial secretory function: a possible mode of action

The effect of the intrauterine contraceptive device (IUD) on the composition of endometrial secretion has been studied using the monoclonal antibody D9B1. The antibody binds to a polypeptide-associated oligosaccharide epitope that is secreted by endometrial epithelium in the secretory phase with a maximum around the time of implantation. In endometria affected by the IUD in situ, a significant reduction in epitope expression has been observed using immunohistochemistry. This defect can occur against a background of normal secretory differentiation and in the expectation of normal ovarian stimulus. The data provide new insight into the contraceptive mechanisms of action of the IUD.

The endometrial cycle: the expression of a secretory component correlated with the luteinizing hormone peak

This paper reports the pattern of production and secretion of a secretory phase epitope in the endometrium of 44 normal fertile women. Peroxidase immunochemistry was used to detect the monoclonal antibody D9B1, which binds to a peptide-associated sialylated oligosaccharide, in endometrial biopsies all chronologically dated from the luteinizing hormone (LH) peak. During the proliferative phase, the epitope was shown to be absent from tissue sections. It first made its appearance within gland cells 2 days after the LH peak. By LH+3 a rapid accumulation of the D9B1 epitope was noted in the base of the cell, below the nucleus. On subsequent days, increasing amounts of the antigen were detected in the apical cytoplasm, apparently in a more concentrated form than in the basal cell zone. On day LH+6, around the time of implantation, secretory vesicles in the cell apex were discharged into the gland lumen where the glycoconjugate finally accumulated. This immunohistochemical approach introduces a new parameter for evaluation of endometrial function and could be used to improve the accuracy of histological assessment of the endometrial cycle.

Luteal phase defect: the possibility of an immunohistochemical diagnosis

Monoclonal antibody D9B1 has been shown to bind to a carbohydrate epitope associated with high molecular weight secretory sialoglycoprotein(s) of human endometrium. The authors demonstrate that, in a group of 28 patients diagnosed on the basis of histopathologic assessment as exhibiting luteal phase defect, 68% reveal significantly diminished expression of the epitope. Furthermore, histologic assessment of the secretory activity in single glands does not correlate simply with the level of expression of the epitope. Of specimens from patients complaining of infertility, 92% showed defective production of the D9B1 epitope. Thus, D9B1 immunohistochemistry provides a new molecular criterion for defective endometrial function.

A novel approach for monitoring the endometrial cycle and detecting ovulation

We report the presence of a cycle-dependent sialoglycoprotein in the endometrium. A monoclonal antibody (D9B1) to this glycoprotein has been derived and used to study tissue from 24 women with normal menstrual cycles. Results obtained with peroxidase immunohistochemistry suggest a highly significant variation in concentration of the glycoprotein, which is absent in the proliferative phase and present at maximal levels in the early secretory phase. The amount of antigen then diminishes slowly through the latter part of the secretory phase. The glycoprotein is produced in epithelial cells of glands and uterine lumen before being secreted across the apical cell surface. The secretory response is uniform in different areas of the tissue and within individual glands. However, considerable differences in secretory activity can be observed between adjacent glands in any part of the endometrium. Binding of the antibody is shown to be a new and novel parameter in characterization and standardization of the normal function of endometrium in response to ovarian hormones.

Surface visualisation of tissue interfaces by scanning electron microscopy. Methods for exposure of the basal lamina and associated structures in human amnion

Tissue interfaces such as basal lamina have been traditionally investigated in transmission electron microscopy by sections cut vertical to the lamina, presenting information restricted to a single ultrathin plane. In order to overcome this limitation, a methodology for surface visualisation of the underside cell membranes of the amniotic epithelium, the upper and lower basal lamina surfaces, and their relationship to the stromal collagen has been devised. This involves alkaline, detergent or enzymatic loosening and/or removal of the epithelial monolayer prior to fixation, followed by dry fracture after critical point drying. In this way we have visualised large areas of all interfaces and the inter-relationships between these elements during the process of stromal collagen production by the amniotic epithelial cells.

Expression of a secretory product by microvillous and ciliated cells of the human endometrial epithelium in vivo and in vitro

A monoclonal antibody which identifies a component of post-ovulatory endometrial secretions is now shown to be expressed within the cytoplasm and on the cell surface of both microvillous and ciliated epithelial cells. A glandular explantation model was developed in order to study the 'carry over' of this secretion to the regenerative phase endometrium. A loss of cytoplasmic antigen was observed in vitro. However, it was retained on the cell surface in a fashion consistent with its expression at the time of explantation. Mosaicism of expression of this secretory component occurs throughout the secretory-phase and is particularly pronounced at the time of transition from proliferative to secretory phase. It is concluded that both ciliated and microvillous epithelial cells produce a post-ovulatory secretory component which may be retained on the cell surface in the absence of hormonal stimulation.

An immunohistochemical study of human endometrial extracellular matrix during the menstrual cycle and first trimester of pregnancy

Changes in the organisation and composition of extracellular matrix in human endometrium during the menstrual cycle and early pregnancy have been assessed by immunofluorescence. Amongst interstitial components, type-III and type V-collagens and fibronectin are present in endometrial stroma throughout the menstrual cycle as well as in first trimester decidua. Type V-collagen epitopes are masked early in the cycle, but become accessible in first trimester decidua. Type VI-collagen is abundant in endometrium in the proliferative phase, but is progressively lost in the secretory phase and decidua, in which it is retained only in blood vessel walls. Vitronectin is present in some blood vessels in decidua. Decidualising stromal cells also produce basement membrane components (type IV-collagen, laminin, heparan sulphate proteoglycan and a glycoprotein family recognised by monoclonal antibody G71) and these become organised into a pericellular aura.

A monoclonal antibody to a cell surface determinant in human endometrial epithelium: stage-specific expression in the menstrual cycle

A monoclonal antibody (CC25) was obtained after immunization of mice with intact glandular epithelial cells from secretory phase endometrium. Here we report a preliminary immunohistologic study in the endometrium of 29 patients in different phases of the menstrual cycle and early pregnancy. In immunofluorescence, CC25 binds to a basolaterally oriented epithelial cell surface antigen that is absent during the proliferative phase and appears suddenly in both glandular and uterine surface locations soon after ovulation. In mid and late secretory phase, the level of expression diminishes slowly. The epitope is absent from glandular epithelial cells in first-trimester decidua. However, it is associated with vascular smooth muscle cells in endometrium and decidua. CC25 promises to be a useful reagent for the analysis of endometrial function during the menstrual cycle.

Importance of vitamin C in maintenance of the normal amnion: an experimental study

Collagenous matrix in amnion accounts for most of the dry weight of the tissue and provides its mechanical strength and resistance to rupture. Cell and organ culture techniques have been utilized to study the influence of vitamin C upon the synthesis and deposition of extracellular matrix by cells of normal amnion at term. The cultures have been examined using light and electron microscopy and metabolic labelling. These studies show that both epithelial cells and fibroblasts of the deeper stromal layer are active in the production of fibrillar matrix at this time. Matrix deposition by epithelial cells in culture increases several-fold when the vitamin C concentration in the supernatant medium is increased from zero to 50 micrograms/ml, and, at the latter concentration, a continuous anastomosing fibrillar collagenous meshwork appears beneath the cells. This study thus provides new evidence that an adequate dietary supply of vitamin C is probably needed to maintain the strength of the chorioamnion.

Monensin-dependent and -independent mechanisms of cell-matrix adhesion

Attachment and spreading of human FL cells on a subcellular matrix (SCM) preparation made by treating confluent cell monolayers with deoxycholate are insensitive to the presence of monensin. However, if the cell suspension is surface-iodinated prior to adhesion using the LPO/H2O2 system, cell spreading on SCM is inhibited by 1 microM monensin. The suggested interpretation is that cell surface components required for cell spreading on SCM are inactivated by iodination and need replacement from intracellular reserves by a monensin-sensitive pathway. This pathway is not required in the absence of iodination when sufficient surface components (or a monensin-independent pathway of surface expression) are available. Support for this interpretation is obtained by means of double-iodination experiments in which surface-labelled cells adhere and spread, are detached and labelled a second time and then allowed to adhere again to SCM. Cell spreading in the second case is inhibited by approximately 80%, suggesting that both previously expressed and newly recruited receptors are inactivated.

An immunofluorescence study of extracellular matrix associated with cytotrophoblast of the chorion laeve

Using immunofluorescence we have studied the distribution within and beneath the cytotrophoblast of chorion laeve of five extracellular matrix components: types I, III and IV collagen, fibronectin and laminin. Fibronectin, laminin and types I and IV collagen are located in a network of extracellular matrix which encapsulates cells of the cytotrophoblast multilayer. The results suggest that cytotrophoblast in all layers is active in matrix biosynthesis. The pseudo-basement membrane, which links this intercellular matrix to the underlying reticular layer, contains rich deposits of fibronectin and type III collagen along with more restricted foci of laminin and type IV collagen. The reticular layer contains fibronectin, type III collagen and small amounts of type I collagen, but no laminin or type IV collagen. Type III collagen is also found in the maternal decidua. Extracellular matrix markers may be useful in defining trophoblast differentiation pathways. Possible reasons are discussed for the unusual architecture of extracellular matrix of cytotrophoblast of the chorion laeve. Cytoplasmic actin occurs in cells throughout the chorion laeve, while cytokeratin appears only in cytotrophoblast. Plasminogen also occurs throughout cytotrophoblast in pericellular locations.

The extracellular matrix of human amniotic epithelium: ultrastructure, composition and deposition

Ultrastructural comparisons have been made between human amnion extracellular matrix in tissue and cell culture. Immunochemical analysis of matrix deposited by monolayers of cultured amnion epithelial cells has also been undertaken. The basal cell surfaces are highly invaginated with an associated basal lamina that is more electron dense at the distal tips of basal cell processes where hemidesmosomes are frequent. Immediately below the lamina densa is a zone rich in collagen bundles. In the underlying stroma two types of fibril predominate, one striated of 50 nm diameter and one of 18 nm diameter. The observations suggest that at gestational term the epithelial cells are still active in the production of matrix. Secretion appears to occur into invaginations in the basal cell surface where a loosely organized mixture of stromal-type and basal laminal-type aggregates is formed. In culture on plastic, cells also deposit a mixture of basal laminal (type IV collagen + laminin) and stromal (collagens type I + III) components as well as fibronectin. However, segregation into a true basal lamina with underlying stroma does not occur in vitro, suggesting the need for an organized subcellular template to complete matrix morphogenesis. The in vitro and in vivo evidence suggest that the epithelium contributes to the subjacent dense collagenous zone as well as to the basal lamina.

Basally located epithelial cell surface component identified by a novel monoclonal antibody technique

Tubular aggregates of glandular epithelial cells (gland fragments) were isolated from human endometrium by collagenase digestion of surrounding stroma, thus exposing the basal surfaces of the cells. Using these aggregates as immunogen, monoclonal antibodies could be derived that recognized basally located antigens. One such antibody, G71, is described, that binds to a basal epithelial cell antigen present in a variety of human epithelia. Epitope-bearing molecules in the range Mr 60 000-180 000 are present in two of the tissues studied, amnion and endometrium. The epitope is associated with areas of epithelial cell-extracellular matrix contact.

Defective adhesion to extracellular matrix leads to altered social behaviour in cultured fibroblasts

We describe the properties of variant mouse fibroblasts selected for poor adhesion to growth substratum containing subcellular matrix accumulated by adherent cells at confluence. The variant cells adhere to virgin plastic and grow normally to confluence in the presence of serum. After subculture and reseeding onto the same surface the cells initially adhere, but after a further 2 days of growth they retract into aggregates and detach. If the aggregates are dispersed and cells reseeded onto the same surface they remain rounded. However, if the same cells are added back to virgin plastic they adhere and grow normally. The retraction can be abolished by treating the subcellular matrix-coated plastic with papain. This behaviour therefore reflects the ability of the cells to modify the composition of the underlying substratum during growth. The variant cells also exhibit retraction 2 days after seeding on a surface previously containing wild-type cells at confluence, while wild-type cells do not retract on subcellular matrix deposited by variants. This shows that the variant behaviour arises not from a deficiency in the subcellular matrix, but from an alteration in the adhesive capacity of the cells. The results are interpreted in terms of three putative adhesion mechanisms: cell-cell adhesion in confluent monolayers and aggregates; ‘early’ type cell-substratum adhesion, which occurs during culture on virgin plastic; and ‘late’ type cell-substratum adhesion occurring on surfaces containing accumulated subcellular matrix. The variant phenotype is characterized by a deficiency in the last of these. It is also associated with an increased ability to grow in suspension culture at high dilution.