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G Stingl

Publications and source records attributed to G Stingl.

At least 109 records · Page 6Linked to original sources
PubMed1993

Somatic gene therapy for cancer: the utility of transferrinfection in generating 'tumor vaccines'.

The last few years have seen the development of a branch of somatic gene therapy which aims at strengthening the immune surveillance of the body, leading to eradication of disseminated cancer tumor cells and occult micrometastases after surgical removal of the primary tumor. Such a tumor vaccination protocol calls for cultivation of the primary tumor tissue and the insertion of one of three types of genes into the isolated cultured tumor cells followed by irradiation of the transfected or transduced cells to render them incapable of further proliferation. The cells so treated constitute the 'tumor vaccine'. A review of the literature suggests that for mouse models, in the initial period after inoculation, rejection of the tumor cells is usually effected by non-T-cell immunity, whereas the long-term systemic immune response is based on cytotoxic T-cells. High expression of the gene inserted into the tumor cells may be critical for the success of the vaccination procedure. Examples are given which indicate that transferrinfection, a procedure to introduce genes by adenovirus-augmented receptor-mediated endocytosis, meets some important prerequisites for successful application of this type of gene therapy.

Animals↗
PubMed1993

Zidovudine in persons with asymptomatic HIV infection and CD4+ cell counts greater than 400 per cubic millimeter. The European-Australian Collaborative Group.

BACKGROUND: Zidovudine therapy is of benefit in the treatment of symptomatic and asymptomatic human immunodeficiency virus (HIV) infection in persons with CD4+ cell counts of less than 500 per cubic millimeter. The efficacy, safety, and duration of benefit of zidovudine in those with 500 or more CD4+ cells per cubic millimeter are uncertain. METHODS: In a double-blind, placebo-controlled trial, 993 patients with asymptomatic HIV infection and CD4+ cell counts above 400 per cubic millimeter were randomly assigned to receive zidovudine (500 mg twice daily) or placebo for three years. The primary end point was progression of disease, as defined by the development of Centers for Disease Control and Prevention (CDC) group IV disease (including recurrent oral candidiasis, hairy leukoplakia, or progressive diarrhea) or two CD4+ cell counts below 350 per cubic millimeter. This outcome measure was changed from the original end point of the acquired immunodeficiency syndrome (AIDS) or advanced AIDS-related complex to reflect changes in recommendations for management. The study was terminated after the first interim analysis. RESULTS: Disease progression was significantly less frequent in the zidovudine group (relative risk, 0.56; 95 percent confidence interval, 0.43 to 0.75; P < 0.001 by the log-rank test). The probability of disease progression at two years was 0.19 with zidovudine, as compared with 0.34 with placebo (95 percent confidence interval for the difference, -0.21 to -0.08). Progression to CDC group IV disease was reduced by half in the zidovudine recipients (relative risk, 0.49; P = 0.049) and decline in CD4+ cell counts to below 350 per cubic millimeter was reduced by 40 percent (relative risk, 0.60; P < 0.001). The inclusion of early HIV disease events (oral candidiasis, oral hairy leukoplakia, and herpes zoster) as end points confirmed the effects of zidovudine on the progression of clinical disease (relative risk, 0.55; 95 percent confidence interval, 0.37 to 0.84; P = 0.004). The median duration of treatment was 94 weeks. Severe hematologic or clinical side effects were rare. CONCLUSIONS: Treatment with zidovudine benefits HIV-infected persons with CD4+ cell counts above 400 per cubic millimeter. Despite the use of doses larger than those now generally prescribed, zidovudine was well tolerated for up to three years by most of our patients.

AIDS-Related Complex↗
PubMed1993

MCP-1 mRNA expression in basal keratinocytes of psoriatic lesions.

In addition to hyperproliferation of keratinocytes, psoriasis is characterized by pronounced leukocytic infiltration. In contrast to the epidermal localization of neutrophils and T lymphocytes, macrophages are almost exclusively restricted to the dermal compartment. By immunohistologic analysis, these dermal macrophages were mainly encountered in the papillary dermis and arranged along the rete ridges in close proximity to proliferating keratinocytes. Monocyte chemoattractant protein (MCP-1) anti-sense RNA probes yielded abundant signals over the proliferating basal keratinocytes of the tips of the rete ridges, and, to a lesser extent, in cells in the papillae. Thus, the strongest MCP-1 message in psoriatic lesions is found above the dermal-epidermal junction and this may explain the characteristic sub-basal distribution of dermal macrophages. These results suggest that MCP-1 is important in regulating the interaction between proliferating keratinocytes and dermal macrophages in psoriasis pathogenesis.

Antigens, CD↗
PubMed1993

In vivo cytokine expression in normal and perturbed murine skin--analysis by competitive quantitative polymerase chain reaction.

Although cells from both epidermis and dermis have been shown to produce a variety of soluble mediators in vitro, it is not clear whether this reflects the in vivo situation. To study in vivo cytokine expression, whole skin as well as dispase-separated epidermis and dermis from normal adult mice were prepared and snap-frozen immediately. RNA was then extracted and analyzed both by conventional and by competitive quantitative polymerase chain reaction. Molecular analysis showed that murine skin in vivo constitutively expresses several cytokine genes at moderate (e.g., interleukin-1 alpha) or low (e.g., interleukin-6 and granulocyte-macrophage colony-stimulating factor) abundance. A striking, rapid upregulation was observed for some of these cytokines in the process of tissue separation. Of interest, the epidermal and dermal compartments exhibited different induction patterns: interleukin-1 alpha, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha expression were detected preferentially in the epidermis, whereas upregulation of interleukin-6 was found to be most prominent in the dermis. This pattern of cytokine expression was also reflected in supernatants generated from the respective single-cell suspensions. Thus, this study determines the baseline in vivo cytokine expression in the skin and the occurrence of immediate, compartment-specific alterations on perturbation. These data should contribute to our understanding of both skin homeostasis and the host-defense mechanisms initiated following injury to this organ.

Amino Acid Sequence↗
PubMed1993

[Immune mechanisms of atopic dermatitis].

The syndrome of atopy consists of three major clinical entities, i.e., allergic rhinoconjunctivitis, allergic asthma and atopic dermatitis, and is usually associated with elevated serum IgE levels. Whereas the pathogenetic role of IgE is clearly established in the case of allergic rhinoconjunctivitis and allergic asthma, the occurrence of atopic dermatitis cannot be easily explained by hyperimmunoglobulinemia E. Atopic dermatitis clinically presents as eczematization of certain predisposed (mostly flexural) areas of the skin. The clinical and histopathological picture, as well as the emergence kinetics of atopic eczema, roughly follow the criteria of delayed type (type IV) immune reactions. It is at present unclear whether the type I-like and the type IV-like allergic reactions of atopy are events occurring independently of each other or, alternatively, are pathogenetically linked to each other. Recent data suggest that in contrast to allergic contact dermatitis where Th 1-like T cells producing interleukin (IL)-2 and interferon (IFN)-gamma are the cells eliciting the lesions, the cellular infiltrate of atopic dermatitis lesions is dominated by Th2 cells capable of producing IL-4 and IL-5. Consequently, two clinical findings of atopic disorders are explicable by the observed Th2 cytokine secretion pattern i.e. i) the hypereosinophilia by the hyperproduction of IL-5 and ii) the hyperimmunoglobulinemia E, for which the presence of IL-4 is a "conditio sine qua non".(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1992

Cytokine pattern of Langerhans cells isolated from murine epidermal cell cultures.

In the present study we demonstrate that supernatants of highly enriched cultured Langerhans cells (cLC) display IL-1, IL-6, granulocyte/macrophage (GM)-CSF, and TNF-alpha, but no IL-2, IL-3, IL-4, and IFN-gamma activities. We further show that IL-6, GM-CSF, and TNF-alpha bioactivities can be specifically blocked in the presence of the respective neutralizing mAb. Concerning the IL-1 bioactivity, the combined use of anti-IL-1 alpha and anti-IL-1 beta mAb was needed to completely inhibit the proliferative response of the indicator cell line D10. One of the difficulties in studying the secretory potential of LC is that even highly enriched cLC are contaminated with keratinocytes (KC), which are known to be a rich source of cytokines. To overcome this problem we compared cytokine bioactivities in supernatants of cell cultures consisting of selected cLC:cKC ratios. These cell mixing experiments revealed that cLC are the major source of the IL-6 bioactivity, whereas IL-1, GM-CSF, and TNF-alpha are predominantly generated by cKC. In order to determine whether the cytokine bioactivities measured in supernatants of epidermal cell cultures are simply caused by an increased release or by de novo synthesis, we performed molecular biologic studies. Polymerase chain reaction analysis of cLC and cKC revealed that IL-1 beta and IL-6 transcripts are virtually limited to cLC, whereas IL-1 alpha, GM-CSF, and TNF-alpha messages are preferentially exhibited by cKC. mRNA coding for IL-2, IL-3, IL-4, and IFN-gamma could neither be amplified from cLC nor from cKC. Furthermore, the quantitative comparison of cytokine transcripts in cLC vs cKC using Northern blot analysis and mRNA detection on the single cell level using in situ hybridization confirmed that cLC generate IL-6, whereas cKC synthesize IL-1 alpha and GM-CSF. Taken together our results demonstrate that cultured murine LC synthesize and secrete IL-1 beta and IL-6, cytokines known to be important accessory molecules in T cell activation.

Animals↗
PubMed1992

Fetal skin: a site of dendritic epidermal T cell development.

Thy-1 Ag and CD3-associated TCR-gamma (V gamma 3)/delta (V delta 1) are coexpressed on virtually all dendritic epidermal T cells (DETC) in the adult mouse. In contrast, day 16 fetal mouse skin contains small numbers of CD45+/Thy-1+/CD3- but no CD3+ cells. To see whether the CD45+/Thy-1+/CD3- fetal skin cells can qualify as DETC precursors, we transplanted day 16 fetal skin of C57BL/6 (Thy-1.2) mice onto adult B6Pl-Thy-1a (Thy-1.1) animals. At certain time points after transplantation, grafts were analyzed for the presence of Thy-1 and CD3/TCR Ag. Examination of the grafts, 4 days after transplantation, revealed the presence of few donor-type Thy-1.2+/CD3- and some Thy-1.2+/CD3+ epidermal cells of either round or dendritic configuration. At 10 weeks after transplantation, essentially all CD45+/Thy-1.2+ epidermal cells were anti-TCR V gamma 3 and anti-CD3-reactive, displayed a uniformly dendritic configuration, and, thus, represent DETC. Our assumption that CD45+/Thy-1+/CD3- cells are the only lymphocytes within day 16 fetal skin gained additional support by the observations: 1) that unfractionated as well as anti-CD45 gated single cell suspensions prepared from day 16 fetal skin were consistently devoid of anti-CD3 epsilon and anti-TCR V gamma 3-reactive cells; and 2) that stimulation of these cell suspensions with either Con A plus IL-2 or IL-2 alone regularly resulted in the outgrowth of CD45+/Thy-1+/CD3-/TCR V gamma 3- cells, but never in the appearance of CD45+/Thy-1+/CD3+/TCR V gamma 3+ cells. Our additional finding that Con A plus IL-2- or IL-2-stimulated day 16 fetal skin cells and cell lines derived therefrom contain transcripts of some (CD3 gamma, TCR C beta, TCR C gamma 1, TCR C gamma 4) but not of other (CD3 delta, CD3 epsilon, TCR C alpha, TCR C delta) genes encoding the CD3/TCR complex suggests that Thy-1+/CD3- fetal murine skin cells are of T cell lineage. We therefore propose that the fetal skin microenvironment can provide the stimuli promoting growth and maturation of CD3/TCR V gamma 3/V delta 1-expressing DETC from their CD3- precursors.

Animals↗
PubMed1992

Demonstration of a CD3+ lymphocyte subset in the epidermis of athymic nude mice. Evidence for T cell receptor diversity.

The existence of CD3/TCR-bearing lymphocytes in athymic and thymectomized chimeric mice implies that T cell maturation can occur in the absence of a thymus. Considering the possibility that the epidermis may be one of the organs providing T cell educating stimuli, we attempted to characterize the Thy-1+ epidermal lymphocyte population of athymic mice. Immunohistologic studies of epidermal sheets revealed (1) that Thy-1+ epidermal cells of C57BL/6 nu/nu mice are CD5-, CD4-, and predominantly CD8-, and (2) that a minor subset of these cells displays anti-CD3 epsilon reactivity. Although these CD3+ epidermal cells could hardly be detected at 6 wk of age, they comprised approximately 2% of all Thy-1+ epidermal cells in 12-mo-old athymic mice. Most of these CD3+ cells expressed TCR-gamma/delta, but TCR-alpha/beta+ cells were also present. TCR-gamma/delta+ epidermal T cells of athymic mice preferentially expressed TCR V gamma 2, V gamma 4, and V gamma 5 specificities rather than TCR V gamma 3 as found on DETC of euthymic mice. Using mitogenic stimuli, we have succeeded in establishing cell lines and clones from BALB/c nu/nu and C57BL/6 nu/nu epidermis. Their marker profile corresponds to that seen on resident CD3+ epidermal cells, as well as on a very small subset of CD3+ splenic and lymph node lymphocytes of athymic mice. The ontogenetic relationship, if any, between the epidermal and lymphoid CD3+, CD5-, CD4-, CD8- cells, has yet to be clarified. Cell lines/clones representative of resident CD3+ epidermal cells of nu/nu mice should provide a useful tool in the elucidation of homing patterns and functional properties of extrathymically matured T cells.

Age Factors↗
PubMed1992

Epidermal Langerhans cells from normal human skin bind monomeric IgE via Fc epsilon RI.

Human epidermal Langerhans cells (LC) bearing IgE are found in disease states associated with hyperimmunoglobulinemia E. When studying the mechanism(s) underlying this phenomenon, immunohistology revealed that a majority of epidermal LC from normal skin of healthy individuals can specifically bind monomeric IgE. IgE binding to LC could neither be prevented by preincubation of the tissue with monoclonal antibodies (mAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32, nor by the addition of lactose. However, binding could be entirely abrogated by preincubation with the anti-Fc epsilon RI alpha mAb 15-1, which interferes with IgE binding to Fc epsilon RI alpha gamma transfectants. These observations indicated that IgE binding to epidermal LC is mediated by Fc epsilon RI rather than by CD23, CD32, or the D-galactose-specific IgE-binding protein. This assumption gained support from our additional findings that: (a) the majority of LC exhibited distinct surface immunolabeling with the anti-Fc epsilon RI alpha mAbs 15-1 and 19-1, but not with any of eight different anti-Fc epsilon RII/CD23 mAbs; and (b) transcripts for the alpha, beta, and gamma chains of Fc epsilon RI could be amplified by polymerase chain reaction from RNA preparations of LC-enriched, but not of LC-depleted, epidermal cell suspensions. In view of the preeminent role of Fc epsilon RI crosslinking on mast cells and basophils in triggering the synthesis and release of mediators of allergic reactions, the demonstration of this receptor on epidermal LC may have important implications for our understanding of allergic reactions after epicutaneous contact with allergens.

Animals↗
PubMed1992

CD69, an early activation antigen on lymphocytes, is constitutively expressed by human epidermal Langerhans cells.

When screening skin cryosections with a panel of monoclonal antibodies (MoAb), we found that the anti-CD69 MoAb Leu-23 reacted with a subpopulation of epidermal dendritic cells, presumably Langerhans cells (LC). The staining intensity was enhanced by gentle trypsin pretreatment of the sections. Flow cytometric analysis of LC-enriched epidermal cells (EC) revealed that nearly all CD1a-bearing LC display anti-CD69 reactivity when tested briefly after termination of the enrichment procedure. Immunoprecipitation experiments showed that isolated LC specifically express a disulphide-linked dimer composed of 26/30kDa subunits that therefore slightly differs from the 28/32kDa CD69 complex described on activated T or natural killer (NK) cells. This difference is probably due to a different post-translational glycosylation pattern as evidenced by Endoglycosidase-F treatment of the immunoprecipitate disclosing the 24-kDa core protein of CD69. When freshly isolated LC-enriched EC were kept in culture, anti-CD69 reactivity gradually decreased but the addition of IFN-gamma to the culture medium sustained the CD69 expression on LC in vitro. These results strongly suggest that resident but not LC recovered from EC cultures bear CD69 moieties. It remains to be seen whether the expression of this antigen can be linked to (a) particular functional property (ies) of intraepidermal LC.

Antibodies, Monoclonal↗
PubMed1992

Isolation of human immunodeficiency virus type 1 from human epidermis: virus replication and transmission studies.

For a better understanding of the pathogenetic events operative in the cutaneous manifestations of human immunodeficiency virus type 1 (HIV-1) disease, we investigated whether epidermal cells (EC) from HIV-1-seronegative persons can be infected with HIV-1 and, vice versa, whether HIV-1 can be rescued from the epidermis of HIV-1-infected individuals. In a series of three experiments, we consistently found that exposure of EC from HIV-1-seronegative donors to HIV-1 led to viral replication in these cells as evidenced by the detection of HIV-1 p24 in culture fluids. Because EC had been substantially enriched for Langerhans cells (LC) before being exposed to HIV-1, it is reasonable to assume that these CD1a+/CD4+/MHC class II+ antigen-presenting cells of the epidermis represented the actual targets of infection. This assumption is further strengthened by the observation that T cell-depleted cell suspensions from Langerhans cell histiocytosis (LCH) lesions could be productively infected with HIV-1. Conversely, co-culture of epidermal sheets from HIV-1-seropositive individuals with mononuclear phagocytes (MNP) from HIV-1-seronegative donors resulted, after 3 to 5 weeks, in the detection of HIV-1 p24 in 12 of 23 cases. Immunocytochemical analysis, using a monoclonal antibody specific for p24, revealed the presence of HIV-1 in adherent MNP in three cocultures tested. In addition, cellular DNA from these cultures showed strong signals when hybridized to a HIV-1-specific DNA probe. The further finding that two isolates examined exhibited different restriction enzyme patterns indicates that they are separate entities rather than contaminants. Transmission of these isolates to MNP, B- or T-cell lines resulted in cultures strongly positive for p24 and, in the case of H9 cells, for viral particles as detected by electron microscopy. Our results therefore strongly suggest that EC not only can serve as targets for HIV-1, but also can allow efficient virus replication and transmit HIV-1 to various cell types of the hematopoietic lineage.

Cell Line↗
PubMed1992

Fc epsilon RI mediates IgE binding to human epidermal Langerhans cells.

In a recent series of experiments, we observed that epidermal Langerhans cells (LC) of healthy, non-atopic individuals have the capacity of specifically binding monomeric serum or myeloma IgE. IgE-binding to LC could neither be prevented by pre-incubation of the cryostat sections with monoclonal antibodies (MoAb) against either Fc epsilon RII/CD23 or Fc gamma RII/CD32 nor by the addition of excess amounts of lactose, but could be entirely abrogated by pre-incubation with the anti-Fc epsilon RI MoAb 15-1. A direct testing of the anti-Fc epsilon RI MoAb 15-1 and 19-1 on cryostat sections in an indirect immuno-double-labeling technique showed that, in contrast to eight different anti-Fc epsilon RII/CD23 MoAb, these MoAb react with the majority of CD1a-bearing epidermal cells. At an ultrastructural level, 15-1 immunogold-labeling in the epidermis was confined to the surface of cells exhibiting Birbeck granules. In further experiments, we were able to amplify by polymerase chain reaction (PCR) technology transcripts for the alpha, beta, and gamma chains of Fc epsilon RI from LC-enriched epidermal cells and dermal cells, but not from LC-depleted epidermal cells. Transcripts for the mast cell enzyme tryptase were exclusively found in dermal cell-derived RNA preparations, thus excluding a contamination of the LC-enriched epidermal cell preparations by dermal mast cells. Collectively, these data show that epidermal LC, but not other epidermal cells, express Fc epsilon RI molecules.

Dermatitis, Atopic↗
PubMed1991

Circulating CD3+/T cell receptor V gamma 3+ fetal murine thymocytes home to the skin and give rise to proliferating dendritic epidermal T cells.

The presence of CD3/TCR V gamma 3 moieties on both dendritic epidermal T cells (DETC) and fetal murine thymocytes has led to the concept that fetal thymocytes expressing this particular TCR phenotype are the actual DETC precursors. To test this assumption, we injected i.v. thymocyte suspensions prepared from day 16 and day 19 fetal mice as well as from adult animals, into syngeneic and Thy-1-disparate nude mice, the epidermis of which contains only Thy-1+/CD3- lymphocytes. Phenotypic analysis of the recipient epidermis by in situ immunolabeling revealed that injection of day 16 and day 19 fetal, but not of adult, thymocytes resulted in the appearance of distinct clusters of DETC as judged by their dendritic morphology and uniform expression of CD3/TCR V gamma 3 receptors. The presence of CD3+/TCR V gamma 3+ cells in the fetal, but not in the adult, thymocyte population(s) together with the failure to detect DETC after transfer of Thy-1+/CD3- fetal thymocytes strongly suggest that CD3+/TCR V gamma 3+ thymocytes are the DETC precursors. Kinetic studies of the DETC population from 2 to 12 wk after cell transfer revealed a substantial increase in the cell density within the DETC clusters that was not accompanied by an increase in the number of clusters. Thus, it appears that newly arriving DETC undergo proliferative activity in situ. Collectively, our results show that, under the experimental conditions chosen, CD3+/TCR V gamma 3+ fetal thymocytes are actual DETC precursors. Although it is not clear whether these experimental conditions are representative of the in vivo situation, they may serve as a useful model for studying the mechanisms underlying the homing properties of different lymphocyte subsets.

Aging↗
PubMed1991

The role of fetal epithelial tissues in the maturation/differentiation of bone marrow-derived precursors into dendritic epidermal T cells (DETC) of the mouse.

Our attempts to clarify the contribution of the thymic vs. the cutaneous microenvironment in the maturation of dendritic epidermal T cell (DETC) precursors into DETC gave diverse results. In one series of experiments, we found that i.v. injection of fetal thymocytes (containing a TCR V gamma 3-expressing subpopulation), but not of adult thymocytes (containing no TCR V gamma 3+ cells) results in the appearance of CD3/TCR V gamma 3+ dendritic epidermal cells (=DETC). In other experiments, we have obtained evidence that transplantation of day 16 fetal skin onto a Thy-1-disparate recipient results in the appearance of donor-type DETC. Our further observation that the transplanted skin contains CD45+/Thy-1+/CD3- lymphocytes, but no mature T cells, therefore implies that fetal skin can provide stimuli promoting the expression of CD3/TCR genes in immature (CD3-) DETC precursors. It remains to be seen whether both or only one of these maturational pathways are (is) followed under physiological conditions.

Animals↗
PubMed1991

Cyclosporin A suppresses ICAM-1 expression by papillary endothelium in healing psoriatic plaques.

To analyze the mode of action of Cyclosporin A (CsA) in psoriasis, we examined the phenotypic profile of resident and passenger skin cells in seven psoriatic patients before and after 2 weeks of CsA treatment using a large panel of monoclonal antibodies in a three-step immunoperoxidase technique. For comparison, skin biopsies from psoriatic patients receiving psoralen + UVA (PUVA) therapy were examined. Although both treatment protocols were equally effective in inducing resolution of psoriatic lesions, the phenotypic changes induced by CsA differed greatly from those seen after PUVA. In CsA-treated patients there was a dramatic reduction in the ICAM-1 expression by papillary endothelial cells, but density, pattern, and phenotype of infiltrating inflammatory cells remained essentially unchanged. In contrast, PUVA therapy had no visible effect on ICAM-1 expression by papillary endothelial cells, but resulted in a significant reduction of the hemopoietic resident and infiltrating mononuclear cells within the epidermis. These results favor, but do not prove, the assumption that the CsA regimen chosen in this study exerts its anti-psoriatic effect primarily at the level of the keratinocyte, i.e., by inhibiting events leading to keratinocyte proliferation as well as by interfering with the secretion of mediators responsible for ICAM-1 expression by papillary endothelial cells.

Adult↗