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Biomedical subjects

A Reano

Publications and source records attributed to A Reano.

35 records · Page 2Linked to original sources
PubMed1986

Precocious appearance of involucrin and epidermal transglutaminase during differentiation of psoriatic skin.

We compared the distribution in psoriatic skin of three different markers usually found in the stratum granulosum of normal skin. Using dansylcadaverine, we demonstrate that epidermal transglutaminase activity can be detected in most of the suprabasal layers of involved psoriatic skin and that the epidermal transglutaminase activity closely matches involucrin distribution. The glycoprotein GP37 was not detected in involved psoriatic skin of stable lesions. These results suggest that the integrated control of several independent pathways of terminal differentiation is lost in psoriasis, resulting in the classical feature of parakeratosis with absence of the stratum granulosum.

Cell Differentiation↗
PubMed1986

GP37 expression in normal and diseased human epidermis: a marker for keratinocyte differentiation.

An antiserum prepared against a glycoprotein (GP37) extracted from the upper epidermal layers, was used to stain frozen sections of human oral mucosa, normal and abnormal skin by an indirect immunofluorescence technique. On normal human epidermis, this antiserum mainly reacted with the cytoplasm of granular cells, whereas on buccal mucosa the recognized antigen was observed as scattered dots limited to the upper epithelial layers. In epidermal diseases, alterations in the staining pattern were observed. In psoriasis, the labelling was markedly diminished; in contrast, in lichen planus it was intense and present on the 3-6 uppermost cellular layers. Basal cell epitheliomas were almost negative, except around horn cysts. In Bowen's disease dyskeratotic cells were strongly labelled. In squamous cell carcinomas a clear-cut staining was observed in squamous nests. On cultures, GP37 expression could be induced by growing epidermal cells in vitamin A-depleted medium. The biological significance of the observed staining patterns remains to be precised. Nevertheless, GP37 represents a sensitive marker of epidermal differentiation and may be useful in skin pathology and in in vitro studies.

Animals↗
PubMed1985

Heterogeneity of thymic epithelial cell (TEC) keratins--immunohistochemical and biochemical evidence for a subset of highly differentiated TEC in the mouse.

The mouse thymic epithelial network was studied using three different anti-keratin antibodies. One of these antibodies, KL1, exclusively recognized a small subset of medullary epithelial cells characterized by its content of a high molecular weight keratin (63 kD). Since epithelial differentiation is known to be associated with the acquisition of high molecular weight keratins, KL1-positive cells, which express the Ia antigen and secrete thymulin, may represent a subset of highly differentiated cells among mouse thymic epithelial cells (TEC). These data reflect the heterogeneity of the thymic epithelium and support the concept that distinct TEC subsets might provide the thymus with different microenvironments.

Animals↗
PubMed1985

A monoclonal antibody labelling the keratinocyte membrane: a marker of epidermal differentiation.

A murine hybridoma secreting an IgM monoclonal antibody (KL3) was produced by cell fusion of mouse myeloma cells with spleen cells from mice immunized with human epidermal keratins. On normal human epidermis KL3 stained the intercellular spaces from the stratum germinatum to the stratum granulosum with a fluorescence intensity increasing from the basal layer to the upper layers. Basal cells were not stained on the side facing the basement membrane. About 90% of free keratinocytes isolated after trypsinization were labelled by KL3 in a punctate staining. Immunoelectron microscopy allowed us to show that the antigen recognized by KL3 was exclusively localized on the keratinocyte membrane especially in the desmosomal plaques. KL3 reactivity was not modified by preincubation of skin sections with lectins showing a selective intercellular labelling of upper layers of epidermis or pemphigus antisera, nor by adsorption of the antibody on NP40 soluble proteins of the epidermis. Though KL3 reactivity was completely abolished after adsorption of purified keratins, no immunological reactivity of KL3 was detected with epidermal keratin polypeptides blotted on nitrocellulose paper. In psoriatic epidemis and epidermal tumors KL3 reactivity was drastically modified. These results suggest that KL3 recognized a keratinocyte membrane antigen implied in the epidermal differentiation process.

Animals↗
PubMed1985

Surface distribution of wheat germ agglutinin binding sites of human melanoma cell lines with low and high tumorigenicity.

Wheat germ agglutinin (WGA) binding patterns of human malignant melanoma cell lines with a high or a low ability to grow subcutaneously in nude mice were compared. SDS-PAGE analysis of WGA binding glycoproteins revealed similar qualitative but different quantitative profiles. Striking differences were observed in the density of WGA binding sites, twice as high in the low tumorigenic cell line as in the high tumorigenic cell line. Differences were also observed in the topographical organization of these WGA binding sites patched on the low tumorigenic cell line and diffuse on the high tumorigenic cell line. Fluorescence photobleaching measurements showed clear-cut differences in their motion patterns.

Cell Line↗
PubMed1984

ConA- and PNA-binding glycoproteins of human epidermis.

Concanavalia ensiformis agglutinin (ConA) and Arachis hypogaea agglutinin (PNA) binding glycoproteins in NP-40 extracts of human epidermis and epidermal cell preparations have been investigated by incubation of SDS-polyacrylamide gels with 125I-labeled lectins. In whole epidermis, 125I-ConA labels numerous glycoproteins, of which some appear to be restricted to the more differentiated upper layers of the epidermis and thus may represent markers of epidermal differentiation. These glycoproteins are not expressed by cells cultured on collagen. 125I-PNA labels a limited number of components, of which the major one is intercellular and/or extremely trypsin-sensitive. This material is expressed in low amounts after 13 days in culture.

Carrier Proteins↗
PubMed1984

Concanavalin (ConA)-reactive human epidermal glycoproteins.

The possibility that glycoconjugates play a role in epidermal differentiation has stimulated attempts at their biochemical identification. We have examined the Concanavalin (ConA)-binding glycoproteins present: in whole human epidermis, epidermal cells obtained by trypsinization of human skin, non dissociated layers (the most differentiated ones) remaining after preparation of these cells and human epidermal cell cultures. 125I-ConA was applied to NP-40 soluble molecules separated by SDS-PAGE. ConA labelling of the whole epidermal extract visualized numerous bands. That of trypsinized cells differed in the intensity of some bands and the absence of others. However most of the latter bands could be identified in the most differentiated layers. These glycoproteins were absent or poorly labelled in the cultures of keratinocytes. The restriction of some ConA-binding glycoproteins to the most differentiated epidermal layers, suggests that these molecules are involved in, or can be considered as markers of the human epidermal differentiative process.

Cell Differentiation↗
PubMed1984

Thymic Hassall's corpuscles-epidermis antigenic relations defined by a common glycoprotein in man (GP 37).

Immunological identification of a common ConA reactive glycoprotein to Hassall's corpuscles (HC) and keratinocytes is reported. By using a gross separation of epidermis into upper and lower layers, we have demonstrated a group of Concanavalin A (ConA) reactive glycoproteins that are characteristic of the upper more differentiated layers of the epidermis. On of them, of 37 Kd MW (GP37), has been immunologically localized within human epidermal granular cells. This limited localization was confirmed by electron microscopy. In thymus, the HC and some medullary epithelial cells were found reactive. This study demonstrated that some thymic epithelial cells from the medulla and the HC shared a defined antigenic specificity common to epidermal granular cells. This immunocytochemical approach and previous ones allow a better understanding of epidermis-thymus interactions.

Antigens↗
PubMed1983

Keratin polypeptide profile in psoriatic epidermis normalized by treatment with etretinate (aromatic retinoid Ro 10-9359).

The variations in the expression of epidermal keratins occurring during retinoid therapy were studied in patients with psoriasis before and during oral administration of etretinate (aromatic retinoid Ro 10-9359) and compared with normal epidermis. Sodium dodecyl sulfate polyacrylamide gel electrophoresis densitometric readings were performed on keratins extracted from epidermal cells obtained through trypsinization of skin specimens. Epidermal cells were also tested by immunofluorescence (IF) for the presence of BMZ antigens as markers of basal cells and for the presence of TK and KP (67 K, 63 K, and 55 K) with sera with antibodies against BMZ antigens and specific antisera for TK and KP. In psoriasis-involved epidermis, SDS-PAGE anaLysis showed lower amounts of 67 K and increased amounts of 63 K and 55 K, as compared with normal epidermis. Low proportions of cells expressing by IF the 67 K and the 63 K were also noted, with a defective expression of these two KP by suprabasal keratinocytes in psoriasis-involved epidermis. During etretinate administration, a return toward the normal electrophoretic pattern and a correction of the defective cellular expression of these two KP were obtained parallel with clinical improvement. These findings indicate the presence in involved psoriatic epidermis of a population of suprabasal keratinocytes that do not express the high-molecular-weight KP and show a normalization of the relative proportions of the KP with etretinate.

Adolescent↗
PubMed1983

Reactivity pattern of a monoclonal antikeratin antibody (KL1).

A monoclonal antibody against keratins (KL1) from normal human stratum corneum was obtained using hybridoma techniques. Spleen cells from immunized BALB/c mice were fused with NS1, a mouse myeloma cell line, to produce hybrids. Antibody activity to epidermal keratins was tested using an indirect immunofluorescence test on cryostat sections of human epidermis and rabbit lip. A stable clone producing antikeratin antibody was isolated and an ascitic fluid was produced and used as a source of antibody (IgG1 kappa). KL1 was characterized by its immunohistochemical staining of various epithelia and by its recognition of 55-57 kilodalton (kd) keratin polypeptide from normal epidermis using the immunoblot technique. Frozen and deparaffinized sections of normal human epidermis, mucosa, and esophagus were stained by this antibody only in the upper cell layers as demonstrated by both indirect immunofluorescence and immunoperoxidase techniques. Approximatively 80% of normal keratinocytes isolated after trypsinization were labeled by KL1 whereas most negative cells showed basement membrane zone antigens. This confirmed differences in the expression of medium-sized polypeptides between basal and supra-basal cells during the course of human epidermal differentiation. All epithelial cells from other human epithelia (thymus, thyroid, bronchial mucosa, stomach, intestines) were positive with KL1 whereas nonepithelial cells and tissues did not show any staining. In view of these results KL1 promises to be a useful tool in the exploration of human epithelial differentiation.

Antibodies, Monoclonal↗
PubMed1982

Expression of common cytoplasmic antigens by epithelial cells of thymus and epidermis.

The expression of common cytoplasmic antigens by thymic epithelial cells and keratinocytes was analyzed by immunolabelling on cryostat sections of human and animal thymus and epidermis. Experimental sera to human epidermal keratin subunits of molecular weight (MW) 67 K, 63 K and 55 K were used, as well as human sera with antibodies to epidermal cytoplasmic antigens (KCA), reacting either with U-Cyt antigens expressed by cells from the upper compartment of the epidermis or with BLC antigens in cells from the basal layer. It was demonstrated that keratin subunits of MW 67 K and 63 K were detected only in the upper layers of human epidermis, whereas 55 K was present in all epidermal layers. On rabbit lip a labelling was obtained throughout the epidermis by the three immune sera. On thymus sections a cytoplasmic staining of epithelial cells was observed with the three immune sera, suggesting an antigenic similarity between cytokeratins of thymus epithelial cells and keratins of the upper layers of human epidermis. Two human sera with U-Cyt antibodies and one with BCL antibodies labelled human thymic epithelial cells but were negative with mice thymus. Ten other sera with KCA were negative on both thymus. These results show that the expression of keratins and cytoplasmic antigens, defined by human KCA, differed in immunofluorescence on normal human epidermis, rabbit lip and thymic epithelial cells. These suggests a heterogeneity among human keratinocyte cytoplasmic antigens defined by KCA and the presence in man of common antigenic constituents from keratins in epidermal cells and thymic epithelial cells.

Animals↗
PubMed1982

Lectins as markers of human epidermal cell differentiation.

The expression of sugar residues on human epidermal cells was investigated by means of lectin binding, as a way of determining membrane structural changes occurring during the differentiation of the epidermis. Fourteen lectins of different sugar specificity were conjugated with fluorescein isothiocyanate (FITC-lectins) and tested in fluorescence microscopy on frozen sections of normal human epidermis. In parallel, FITC-lectins were tested on psoriatic-involved epidermis to visualize differences in the expression of sugar residues that might occur during abnormal epidermal differentiation. No labelling could be obtained with lectins from Bandeira simplicifolia I, Dolichos biflorus, Limulus poyphemus, Tetragonolobus purpureas, Ulex europeus I, and Triticum vulgaris (group 1 lectins). A "pemphigus-like" intercellular labelling of the whole epidermis, except the stratum corneum, was obtained with lectins from Canavalia ensiformis. Maclura pomifera, Phaseolus vulgaris, and Ricinus communis I (group 2 lectins). A selective intercellular labelling of the stratum spinosum and the stratum granulosum was seen in normal epidermis with lectins from Arachis hypogaea, Glycine max, Helix pomatia, and Sophora japonica (group 3 lectins). In psoriatic epidermis, not only the basal cell layer, but also cells from the adjacent lower stratum spinosum were found to be negative, using FITC-lectins of group 3. These data indicate that the expression of lectin binding sites in normal epidermis differs according to the maturation of the cell from the basal cell to the more mature keratinocyte in the stratum granulosum. They suggest that lectins may be used as markers of epidermal cells in various stages of normal and abnormal differentiation.

Cell Differentiation↗
PubMed1982

Cytokeratins in human basal and squamous cell carcinomas: biochemical, immunohistological findings and comparisons with normal epithelia.

The nature of epithelial cell cytokeratins from epidermal basal cell carcinomas (BCC) (8 cases) and squamous cell carcinomas (SCC) (5 cases) was investigated by biochemical and immunological analysis. Cytokeratin proteins were extracted with high salt buffer and triton X 100 and were comparatively analyzed by SDS (sodium dodecyl sulphate) polyacrylamide gel electrophoresis. Both types of tumor showed either an absence or a very low amount (5% of the total protein) of the major protein band (MW 67000) present in normal human epidermis. This correlated well with results of immunolabelling showing that 67000 keratin antisera, only reacted with some dyskeratotic cells in sections of these tumors. Gel electrophoresis showed in BCC and SCC, three distinct groups of predominant polypeptide bands of apparent relative MW: (1) 60-62000 (2) 54-56000 and (3) 49000, representing respectively about 43.0%, 31.0% and 20.4% of the total proteins. Antibodies raised in animals against polypeptide bands C1 (MW 62000), C2 (MW 56000) and C3 (MW 49000) from SCC, strongly labelled (indirect immunofluorescence) all malignant cells present in the 2 kinds of tumors. These antisera showed a preferential reaction with the basal epithelial cells, in sections of human and animal epidermis and mucosa thus, suggesting numerous common antigenic determinants between epithelial cells from diverse origins. On the other hand, strong differences between mucosal and epidermal upper layers were noted with C1, C2, C3 and 67000 antisera. These results are further evidence for the existence of different pathways of keratinization in epidermis and mucosa.

Animals↗
PubMed1982

[Monoclonal antibodies (BL7 and BL9) having crossed reactivity with cells of the human epidermis].

The relationships between epithelial cells and immunocompetent cells could be approached by studying of the common antigens expressed by these two cell types. This paper reports the study of two monoclonal antibodies (BL7 and BL9) which react with epidermal cells. BL7 was obtained after immunization of mice with human thymic cell suspensions and BL9, after immunization with Raji cells. BL7 stained the epithelial network of the thymus and the basal cell layer of the epidermis. BL7 also reacted with the endothelial cells of the vessels of the dermis. This reactivity against the basal cell layer of the epidermis was observed in man, mice and rabbit. BL9 showed a reactivity against thymic epithelial cells and stained the membrane of the keratinocytes of the human epidermis. The antigenic expression revealed by BL9 decreased during the epidermal cell differentiation and disappeared in the horny layer. BL9 showed no reactivity with the epidermis of mice and rabbit. These two monoclonal antibodies are new tools in cutaneous immunopathology: BL7 is the first monoclonal experimental marker which identifies the basal cells of the epidermis, BL9 identifies an antigen related to the human epidermal cell differentiation.

Animals↗