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G Stingl

Publications and source records attributed to G Stingl.

At least 163 records · Page 9Linked to original sources
PubMed1986

Interleukin 2 receptors on cultured murine epidermal Langerhans cells.

Rat monoclonal antibodies 3C7 and 7D4 detect two distinct functional regions of the murine interleukin 2 (IL 2) receptor. When studying the emergence kinetics of IL 2 receptors in mixed epidermal cell (EC)-lymphocyte cultures by using 3C7 and 7D4 in an indirect immunofluorescence assay, we regularly encountered a distinctive membrane fluorescence not only on lymphocytes, but also on a subpopulation of cells exhibiting a dendritic morphology. Reasoning that these 3C7/7D4-reactive dendritic cells might represent a subpopulation of epidermal dendritic cells, we studied mouse EC for the presence of 3C7/7D4- reactive cells. Although 3C7/7D4 reactivity was never detected on freshly isolated EC or on epidermal sheets, a small number of 3C7/7D4+ cells was encountered after 24 to 48 hr of culture. These cells exhibited a dendritic shape, expressed Ia antigens, lacked Thy-1 antigens, and displayed the ultrastructural features of Langerhans cells (LC) with the notable exception of Birbeck granules. Although after 24 hr, only 20% of Ia+ EC were 3C7/7D4+, the vast majority of LC displayed 3C7/7D4 binding sites after 4 to 5 days of culture. Preincubation of cultured LC-enriched EC with recombinant human IL 2 prevented subsequent 3C7-but not 7D4-binding to these cells. Western blot analysis of 7D4-reactive material of detergent extracts from LC-enriched EC revealed three bands in the same m.w. range as reported for CTLL cells. These results demonstrate that cultured LC express IL 2 receptors and may bear important implications for a better understanding of growth regulation, differentiation, and immunologic functions of LC.

Animals↗
PubMed1986

Effects of physicochemical agents on murine epidermal Langerhans cells and Thy-1-positive dendritic epidermal cells.

The possibility that Thy-1-positive dendritic epidermal cells (Thy-1+DEC) may contribute to the immunologic functions of murine epidermal cells (EC) prompted us to simultaneously assess the effects of certain immunomodulating physicochemical agents on both Thy-1+DEC and Ia-bearing Langerhans cells (LC). C3H/He mice received one of the following treatment modalities: UV-B irradiation (four consecutive days); psoralen plus UV-A (PUVA; three times a week for three consecutive weeks); topically and systemically applied glucocorticosteroids (GCS). Beginning 2 days after the last treatment, animals were sacrificed and the structure and surface marker expression of Ia+EC and Thy-1+DEC were assessed by immunohistologic means on epidermal sheet preparations from ear skin by using appropriate monoclonal antibodies. Whereas low-dose UV-B irradiation (4 X 100 or 200 J/m2) had little, if any, effect on either Ia+EC or Thy-1+DEC, high-dose UV-B (4 X 700 or 1000 J/m2) or PUVA treatment led to an almost complete disappearance of both surface characteristics. Immunoelectron microscopic studies revealed that in the case of LC, high-dose UV-B or PUVA treatment results in the disappearance of their anti-Ia reactivity but leaves their ultrastructural morphology intact. In sharp contrast, Thy-1+DEC escape ultrastructural detection after PUVA treatment and are greatly reduced in number after high-dose UV-B. Ia+EC continuously reappeared with both treatment modalities over a course of 4 to 6 wk, whereas even after 14 to 22 wk Thy-1+DEC were present only in negligible numbers. Similar to high-dose UV-B or PUVA therapy, administration of GCS resulted in the disappearance of both anti-Thy-1- and anti-Ia-reactive cells. Ultrastructural studies disclosed, however, that these steroid-induced alterations in the surface characteristics were accompanied by a dramatic reduction of the LC population but were not paralleled by morphologic changes of Thy-1+DEC. In the course of 7 wk after cessation of steroid treatment, the number of both Ia+EC and Thy-1+DEC had returned to normal values. The selective removal of either of these two dendritic epidermal cell populations by physicochemical agents may provide an excellent strategy to further clarify the functional properties of both LC and Thy-1+DEC.

Animals↗
PubMed1986

Leu-3/T4 expression on epidermal Langerhans cells in normal and diseased skin.

Recent evidence exists that the expression of the Leu-3/T4 antigen is not restricted to thymus-derived lymphocytes but can also be detected on mononuclear phagocytes and epidermal Langerhans cells (LC). When searching for the presence of Leu-3/T4 antigen-bearing cells in tissue sections of a variety of inflammatory and neoplastic skin disorders, we observed quantitative and qualitative differences in the intensity of anti-Leu-3a labeling of epidermal dendritic cells. Reasoning that Leu-3/T4 expression by these cells might be a dynamic event, we compared the anti-Leu-3a LC staining pattern in clinically normal-appearing skin (CNAS) with the expression of this antigen on epidermal dendritic cells in a variety of skin disorders. For this purpose, 4-microns cryostat sections were exposed to the monoclonal anti-Leu-3a reagent and antibody binding was visualized by a sensitive 4-step immunoperoxidase technique. Within CNAS, Leu-3a+ dendritic epidermal cells were visualized at the threshold of detectability. Immunoelectron microscopic studies confirmed the LC nature of these cells. In sharp contrast to CNAS, strong and prominent anti-Leu-3a LC labeling was almost invariably encountered in biopsy specimens from patients with cutaneous T-cell lymphoma and various inflammatory conditions but not in proliferative disorders of resident skin cells. Whereas in CNAS the density of T6+ epidermal dendritic cells greatly exceeded that of anti-Leu-3a-reactive dendritic cells, these differences were less pronounced in diseased skin. Our results: confirm earlier observations that epidermal LC may bear Leu-3/T4 antigens; and in addition, suggest that the degree of Leu-3/T4 expression is regulated by signals from inflammatory cells. The induction of class II alloantigen receptors on class II alloantigen-bearing LC may represent an important regulation mechanism of antigen-presenting cell function.

Adolescent↗
PubMed1985

[Acquired immune deficiency syndrome (AIDS)].

Acquired immune deficiency syndrome (AIDS) is a new disease caused almost certainly by a transmissible agent, which is most likely a retrovirus termed HTLV-III. The disease is mainly spread by sexual, especially homosexual contact. Blood-borne transmission is another recognized form of spreading of the disease; it seems, however, that the disease is not readily spread via casual, non-sexual, or other than blood-borne routes. Although the disease is still concentrated in the major metropolitan areas of the United States, it is now increasingly observed in several countries throughout the world. The basic characteristic of the disease is a profound dysregulation of the immune system as proved by a qualitative and quantitative defect of helper T-lymphocytes as well as by B-cell hyperactivity. Clinical manifestations are those of severe and life-threatening opportunistic infections and unusual neoplasms, particularly Kaposi's sarcoma. The mortality is extremely high and may well approach 100%. Therapeutic efforts include the treatment of opportunistic infections and the search for agents which may reconstitute immunologic competence.

Acquired Immunodeficiency Syndrome↗
PubMed1985

The Thy-1-bearing cell of murine epidermis. A distinctive leukocyte perhaps related to natural killer cells.

Bone marrow-derived leukocytes of murine epidermis can express two phenotypes: typical Langerhans cells, which are Ia+ and Thy-1-, and a recently discovered second population that is Thy-1+ and Ia-. To verify that these phenotypes are expressed by two different cell types, and to help understand their lineage and function, we have studied morphology and reactivity with a large panel of antibodies. Dual antibody immunofluorescence combined with electron microscopy showed that Thy-1+ and Ia+ cells were each distributed in a regular fashion and formed adjacent dendritic systems in or close to the basal layer. Double-labeling studies with anti-Ia and a second monoclonal antibody revealed that all Langerhans cells expressed F4/80 (macrophage), Mac-1 (C3bi receptor), and 2.4G2 (Fc receptor), as well as the thymus leukemia (TL) and heat-stable (M1.69/16) antigens. A large fraction expressed S100 and all exhibited membrane ATPase and nonspecific esterase. In contrast, Thy-1+ cells lacked all these features of Langerhans cells, except that a minority were strongly reactive with 2.4G2. Thy-1+ cells also lacked differentiation antigens of most other types of leukocytes, except they were rich in asialo GM1. By electron microscopy, Thy-1+ cells had cytoplasmic granules that were similar in structure and in their aryl sulfatase content to those previously described in natural killer cells. The granules were enlarged in beige mice, suggesting a lysosomal origin, and were present in mast cell-deficient W/Wv mice, indicating no relation to mast cells. We conclude that Thy-1+ epidermal cells are thoroughly distinct from Langerhans cells. On the basis of morphology and phenotype, they may represent a type of tissue natural killer cell. Thy-1+ natural killer cells are now being identified in several nonlymphoid sites, such as gut epithelium and the livers of mice given adjuvants. If Thy-1+ epidermal cells prove to be natural killer cells, it is noteworthy that they represent a resident population regularly distributed in the basal layer of all mouse strains. The notion that Thy-1+ epidermal cells are immature natural killer cells is intriguing in light of recent evidence that Ia+ Langerhans cells are also immature with respect to accessory cell function. The epidermis may not have the functional capacities of a lymphoid organ, but it could contribute immature cells important for both natural and acquired resistance.

Animals↗
PubMed1985

Human epidermal cells synthesize HLA-DR alloantigens in vitro upon stimulation with gamma-interferon.

Under certain pathologic conditions, human keratinocytes synthesize and express HLA-DR antigens. Assuming that soluble mediators might be responsible for this phenomenon, differentiating, primarily DR-keratinocytes were grown in the presence or absence of mixed leukocyte culture supernatants and tested for Ia antigen expression. After 6 days of culture, keratinocytes displayed surface-bound HLA-DR alpha/beta complexes when exposed to mixed leukocyte culture supernatants but not when cultured in media alone. These HLA-DR moieties on keratinocytes result from active biosynthesis as evidenced by the demonstration of the intracytoplasmic HLA-DR gamma (invariant) chain within these cells. In view of reports that interferon-gamma promotes Ia-production in a variety of cell types, we reasoned that this lymphokine might be responsible for the Ia-inducing property of mixed lymphocyte culture supernatants. Indeed, recombinant interferon-gamma, but not interferon-alpha or interleukin-2, proved to be a potent stimulator of Ia expression by keratinocytes. The further finding that this event can be prevented by the addition of a monoclonal anti-interferon-gamma antibody strongly suggests that this cytokine is directly responsible for HLA-DR production by keratinocytes. The interferon-gamma-induced acquisition of HLA-DR antigens by primarily DR-keratinocytes may provide a useful tool to study the role of these alloantigens in T-cell activation and may also add to our understanding of mechanisms operative in epidermal cell-T-cell interactions.

Antibodies, Monoclonal↗
PubMed1985

Expression of the Ly-5 alloantigenic system on epidermal cells.

The expression of Ly-5 alloantigens is confined to hemopoietic cell types and is therefore considered a valuable indicator for the bone marrow derivation of a given cell. The further finding that different hemopoietic cell lineages express different molecular forms of the Ly-5 alloantigens prompted us to investigate (1) whether murine epidermal cells or subpopulations thereof express Ly-5 specificities and if so, (2) whether the expression of particular molecular configurations of Ly-5 antigens would allow us to gain a clue about the derivation of certain epidermal cell populations. When epidermal sheets from BALB/c, C57Bl/6, and C3H/He mice, were exposed to monoclonal anti Ly-5.1 antibody in an indirect immunofluorescence technique, a system of evenly distributed, dendritic cells was visualized. Allelic exclusion of the Ly-5 system was demonstrated by replacing anti-Ly-5.1 antibody by anti-Ly-5.2 reagent and by using epidermal sheets from SJL/J mice. Studies on epidermal cell (EC) suspensions revealed that about 1.6-5.2% of C3H/He EC were Ly-5-reactive and that approximately equal numbers of Ly-5-positive cells bore either Thy-1 or Ia antigens. Electron microscopic studies disclosed two morphologically different Ly-5-positive cell populations, i.e., cells of the Langerhans cell lineage and a recently defined cell system, whose most prominent feature is the expression of the Thy-1 antigen. We have termed these cells dendritic Thy-1+EC (dTHY-1+EC). In order to define the molecular configurations of the Ly-5 alloantigens, EC and spleen cells were internally labeled and--after immunoprecipitation of cell-membrane detergent extracts with anti-Ly-5.1--were analyzed on sodium dodecyl sulfate-polyacrylamide gels. Spleen cells yielded 3 bands with a molecular weight of 180,000, 195,000, and 215,000, respectively, as is characteristic for T lymphocytes, non-T/non-B cells, and B lymphocytes. In contrast, a single 195,000-200,000 dalton band was found in precipitates of both untreated and Langerhans cell-depleted (anti-Ia+C) EC. These data demonstrate the existence and active biosynthesis of the Ly-5 alloantigenic system on certain EC populations, i.e., Langerhans cells and dThy-1+EC, and therefore imply that both cell types originate from a bone marrow-derived precursor. The expression of the same molecular configuration of Ly-5 alloantigens on both LC and dThy-1+EC suggest that these two cell populations do not belong either to the T-cell or to the B-cell lineage and imply an ontogenetic relationship between dThy-1+EC and Ia-positive EC.

Animals↗
PubMed1985

Morphological and phenotypical characterization of bone marrow-derived dendritic Thy-1-positive epidermal cells of the mouse.

Increasing evidence exists that the spectrum of dendritic cells within the epidermis is more complex than previously thought. In addition to Langerhans cells, Merkel cells, and melanocytes, the murine epidermis contains a dendritic cell population whose most prominent phenotypic feature is the Thy-1 antigen. These cells are now generally referred to as dendritic Thy-1+ epidermal cells (dThy-1+EC). The ultrastructural features of these cells do not resemble those of other resident epidermal cells (EC). In particular, their cytoplasm contains abundant intermediate-sized filaments of the vimentin type as well as membrane-limited organelles with a central granular core. The bone marrow derivation of dThy-1+EC is now well established: dThy-1+EC carry Ly-5 determinants whose expression is restricted to cells of the hemopoietic differentiation pathway, and studies using Thy-1-disparate radiation bone marrow chimeras have revealed the presence of donor-type Thy-1+ cells within the epidermis; by immunoelectron microscopy, these cells represent dThy-1+EC. dThy-1+EC repopulate the epidermis at a slower rate than Langerhans cells as evidenced by a direct comparison of the repopulation kinetics of both cell systems in radiation bone marrow chimeras, and by experiments studying the emergence of either Ia+- or dThy-1+EC in an epidermis which had been previously depleted of either Langerhans cells (glucocorticosteroids) or of dThy-1+EC (PUVA). The phenotypical features of dThy-1+EC differ from those of thymus-derived lymphocytes, B cells, dendritic cells, and mononuclear phagocytes. The surface marker repertoire of dThy-1+EC (Thy-1, Ly-5, asialo-GM1) resembles certain members of the rather heterogeneous natural killer (NK) cell system but functional studies are needed to ascertain this contention.

Animals↗
PubMed1985

Inhibition of DNA synthesis of melanoma cells by azelaic acid.

Azelaic acid was successfully used in the clinical treatment of 7 cases of lentigo maligna in that remission of the lesions was observed in all our patients. In order to elucidate mechanism(s) of the beneficial clinical effects, we studied the effect of azelaic acid on cultured melanoma cells. Cell numbers recovered from melanoma cell cultures grown for several days in the presence of 10 mM azelaic acid were 50-70% less than those recovered from control cultures or from cultures containing 10 mM adipic acid. This reduction of cell numbers was not due to a simple cytotoxic or cytolytic effect of azelaic acid but rather due to a dose-dependent inhibition of DNA synthesis. Interestingly, nontoxic concentrations of azelaic acid, which significantly reduced DNA synthesis of cultured melanoma cells, had no overt effect on the protein synthesis of these cells. It is conceivable that inhibition of DNA synthesis is one of the mechanisms by which azelaic acid prevents growth and proliferation of abnormal melanocytes.

Administration, Topical↗
PubMed1985

Epidermal cells as accessory cells in the generation of allo-reactive and hapten-specific cytotoxic T lymphocyte (CTL) responses.

The capacity of epidermal cells (EC) to stimulate T cell activation is a Langerhans cell (LC)-dependent phenomenon. In all in vitro assays probed, LC subserve antigen-presenting cell functions in that they display surface-bound foreign or altered-self structures and thereby activate T cell responses. In contrast, attempts to demonstrate accessory cell (ACC) function of LC-containing EC have yielded negative results, i.e., EC lacking foreign cell surface antigens were not able to restore cytotoxic T lymphocyte (CTL) responses in Ia+ adherent cell-depleted cultures. Reasoning that the ACC function of EC might be critically linked to cluster formation between LC and other cell types involved, we tested the ACC function of EC under experimental conditions that allow a close physical contact between the cell types involved (round-bottomed microtiter plates and brief centrifugation of culture plates). By using these modifications, the failure of highly purified B6 T cells to develop alloreactive CTL activity when stimulated with either highly purified, mitomycin C-treated C3H or B6CF1 T cells was restored by the addition of B6 EC. The CTL thus generated produced significant lysis of Con-A-stimulated C3H or BALB/c, but not B6, spleen cell targets. In a similar fashion, TNP- or FITC-specific CTL were generated when (in a syngeneic system) mitomycin C-treated TNP- or FITC-modified stimulator T cells and responder T cells were co-cultured in the presence, but not in the absence, of unmodified EC. The capacity of EC to restore CTL activity in a culture system depleted of Ia-bearing cells was not dependent upon their H-2 type, but was critically linked to the presence of Ia-bearing LC. We therefore conclude that LC-containing EC can subserve the ACC function in the generation of H-2-restricted CTL, provided that culture conditions are chosen that allow a close physical contact between the cell types involved.

Animals↗
PubMed1985

Thymopentin treatment of herpes simplex infections. An open, monitored, multicenter study.

Twenty-seven patients suffering from long-standing, severe, recurrent herpes simplex (14 labial and 13 genital) who had not responded adequately to prior therapy were recruited for this open, monitored study. They were treated with thymopentin 50 mg subcutaneously three times weekly for a period of 6 weeks. Clinical controls were performed once a week and then again 6 weeks after cessation of therapy; laboratory investigations were done at time points 0, 3, and 6 weeks. Additionally, information was collected with regard to the clinical course during the following year. Thirteen of 14 patients with labial infection and 10 of the 13 with genital herpes improved markedly (p less than 0.05) as shown by decrease in the relapse rate of at least 50%, shorter relapse episodes, and improvement of symptoms such as pain and itching. Fourteen of these 27 patients experienced no relapse for a period longer than 4 months after cessation of therapy. These favorable results were paralleled by a statistically significant increase in the T cell helper/suppressor ratio. This finding indicates that thymopentin acts as an immunodomulator; it is assumed that the activation of T helper cells induces-presumable via interleukin 2-the proliferation of cytotoxic T lymphocytes and natural killer cells which play a major role in the natural immune defense. No serious side effects of thymopentin were recorded.

Adjuvants, Immunologic↗
PubMed1984

Evidence of HLA-DR antigen biosynthesis by human keratinocytes in disease.

As opposed to normal human skin where HLA-DR expression is restricted to the Langerhans cell (LC) population, HLA-DR, but not HLA-DS antigens can be readily detected on keratinocytes (KC) in certain disease states, i.e., cutaneous T cell lymphoma (CTCL), graft-vs-host disease (GVHD), and lichen planus (LP). To clarify the cellular origin of KC-bound HLA-DR antigens, we used a monoclonal antibody directed against determinants solely expressed on the cytoplasmic HLA-DR gamma chain (VIC-Y1) and observed that, by immunofluorescence, KC displaying HLA-DR alpha/beta complexes on their surface uniformly displayed cytoplasmic VIC-Y1 reactivity. In view of the crucial role of the gamma chain for HLA-DR biosynthesis, we conclude that HLA-DR antigens on KC are actively synthesized by these cells.

Epidermis↗
PubMed1984

The effect of thymopentin treatment on the relapse rate in frequently relapsing herpes simplex virus infections.

Twenty-four patients suffering from longstanding severe recurrent herpes simplex, who had not responded to prior therapy, were treated with s.c. thymopentin injections 50 mg, three times weekly, over a period of six weeks. They were followed up at weekly intervals over this period and then six weeks later. Moreover, the longest relapse-free period observed in the year after the treatment was recorded in the investigator's documentation. Thirteen of the 14 patients with labial herpes simplex and 10 of the 13 patients with genital herpes simplex improved markedly as shown by a decrease in the relapse rate of at least 50%, shorter episodes of relapse and improvement of symptoms such as pain and itching. Fourteen of these 27 patients experienced no relapse for a period longer than four months after cessation of the therapy. No serious side-effects were observed. Laboratory examinations before, during and after thymopentin did not reveal significant alterations except for an increase in the T-helper/T-suppressor ratio. The effect of thymopentin is assumed to be due to T-helper cell activation resulting in enhanced interleukin-2 production with subsequent proliferation of cytotoxic T lymphocytes and natural killer cells which are capable of producing immune interferon.

Adult↗
PubMed1984

A human Ia cytoplasmic determinant located on multiple forms of invariant chain (gamma, gamma 2, gamma 3).

An antigenic determinant present in the cytoplasm, but not on the surface membrane of human Ia+ cells, is defined by a monoclonal antibody (VIC-Y1) and is shown by immunoprecipitation and by NEPHGE to be expressed by Ia oligomers. Immunoprecipitations of cellfree translates and of purified Ia subunits indicate that the VIC-Y1 determinant is located on the Ia gamma-(invariant) chain, as well as on two other related molecules, provisionally termed gamma 2 and gamma 3. Within our experimental conditions, the three forms of gamma-chains co-precipitate exclusively with Ia oligomers. As detected by VIC-Y1 and in the limits of our assays, gamma-chains could not be found at the cell surface; their tissue distribution, determined by cytoplasmic indirect immunofluorescence with VIC-Y1, closely resembles that of Ia antigens, with the possible exception of acute lymphatic leukemia cells (Ia+, gamma-chain-).

Animals↗
PubMed1984

Effect of glucocorticosteroids on epidermal cell-induced immune responses.

Recent reports indicate that pharmacologic doses of glucocorticosteroids induce structural alterations in epidermal Langerhans cells. In this study we hoped to determine whether steroid-induced changes in Langerhans cell surface characteristics are paralleled by alterations in Langerhans cell-dependent immunologic functions of epidermal cells. We found that both topically and systemically administered steroids led to a dose-dependent reduction in the number of Ia-bearing epidermal cells. This numerical decrease was paralleled by a substantial impairment of Langerhans cell-dependent immunologic functions of epidermal cells in that their capacity to induce antigen-specific, syngeneic, and allogeneic proliferation of T cells from non-steroid-treated animals was substantially reduced. The capacity of epidermal cells to generate ETAF activity, however, was not adversely affected by the steroid treatment. After cessation of treatment, Langerhans cell numbers and Langerhans cell-dependent in vitro functions slowly and gradually returned to normal values. We propose that the ability of glucocorticosteroids to interfere with the generation of T cell-dependent immune responses may be due, at least in part, to their interference with antigen-presenting cell function.

Animals↗