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P Petzelbauer

Publications and source records attributed to P Petzelbauer.

At least 37 records · Page 2Linked to original sources
PubMed1998

MCP-1 and MIP-1alpha are most efficient in recruiting T cells into the skin in vivo.

To analyze T cell recruitment by chemokines in vivo, we used SCID mice grafted with human skin onto their backs and human T cells into their peritoneal cavities. rh MIP-1alpha and rh MCP-1, as well as mouse MCP-1, attracted significant amounts of human T cells into human skin grafts, whereas effects of rh RANTES, rh SDF-1, or rh IP-10 were minimal. Human T cells were found in a striking perivascular position exclusively at sites of human endothelium. None of the chemokines recruited human T cells across mouse endothelial barriers. For control purposes, chemokines were injected into the abdominal wall directly above the peritoneal cavity, where human T cells had been injected and were not subjected to flow. At this site all tested chemokines attracted human T cells to an equal extent. In summary, our experiments point towards an important role for MCP-1 and MIP-1alpha as T cell chemoattractants for skin inflammatory conditions.

Animals↗
PubMed1997

Endothelial cell tube formation depends on cadherin 5 and CD31 interactions with filamentous actin.

Capillary tube formation represents a specialized endothelial cell function and is a prerequisite for the establishment of a continuous vessel lumen. Tube formation is thought to depend on cell-cell adhesion molecules, but whereas cadherins, Ig superfamily proteins, and integrins have been considered as potential candidates, the specific proteins subserving this function are unknown. We identified cadherin 5 and CD31 as two molecules critical for endothelial cell tube formation. Using human dermal microvascular endothelial cells or human umbilical vein endothelial cells for an in vitro capillary tube formation assay or, for comparison, an in vivo wound healing model in SCID mice, we show that tube formation in vivo and in vitro were prevented by adhesion-blocking mAbs to both proteins when used in conjunction but not by either mAb alone. In addition, both mAbs but not each individual mAb blocked cytoplasmic filamentous actin (F-actin) reorganization that resulted in cytoplasmic F-actin clumps similar to those induced by cytochalasin D, suggesting that cadherin 5 and CD31 tune tube formation in concert with F-actin. Indeed, cytochalasin D blocked capillary tube formation but colchicine did not, the latter inhibiting microtubule but not F-actin assembly. Using immunoprecipitation methods, we show for the first time that not only cadherin 5 but also a portion of CD31 connects to beta-catenin, which is part of the adherens junction complex known to be linked to F-actin. In conclusion, we provide evidence that cadherin 5, CD31, beta-catenin, and F-actin shape a functional complex that controls endothelial cell tube formation.

Actin Cytoskeleton↗
PubMed1997

MUC18/MCAM (CD146), an activation antigen of human T lymphocytes.

Extravasation and tissue infiltration of leukocytes and metastatic tumor cells require the regulated expression and function of adhesive and pro-proteolytic surface molecules. We demonstrate here that human T cells, upon activation, neo-express the melanoma metastasis-associated surface molecule MUC18/melanoma cell adhesion molecule (MCAM). Expression of MUC18/MCAM (CD146) on T cells could be identified with two mAbs (541-10B2 and 541-2E5) obtained after immunization with HUT102 T cells and found to react with activated T cells. The specificity of our mAbs for MUC18/MCAM (CD146) was revealed by 1) definition of the appropriate molecular mass of approximately 110 kDa unreduced and 120 kDa reduced, 2) reactivity of mAbs with MUC18/MCAM (CD146) cDNA-transfected mouse L cells, 3) conclusive crosswise immunoblotting experiments with MUC18/MCAM (CD146)-specific mAbs, and 4) N-terminal amino acid sequencing of precipitated protein. In vitro activation by PHA caused neo-expression of MUC18/MCAM (CD146) on peripheral blood T cells within 1 day of stimulation, reaching a maximum on day 3. In vivo expression of MUC18/MCAM (CD146) was confirmed on CD3+ T cells infiltrating delayed-type hypersensitivity lesions of the skin, on synovial fluid T cells of rheumatoid arthritis patients, and on distinct T leukemia cells. MUC18/MCAM (CD146) cell surface expression on activated T cells is mirrored by the presence of specific mRNA. Leukocytes of healthy donors do not show significant MUC18/MCAM (CD146) expression. The finding that MUC18/MCAM (CD146) is also expressed on activated T cells might suggest that this adhesion molecule is involved in the extravasation and/or homing of activated T cells.

Antibodies, Monoclonal↗
PubMed1997

HECA-452+ T cells migrate through superficial vascular plexus but not through deep vascular plexus endothelium.

The skin is nourished by two interconnected vascular systems, the superficial vascular plexus coursing just beneath the epidermis and the deep vascular plexus located above the subcutaneous tissue. Skin inflammatory T cells in diseases, such as psoriasis or dermatitis, strikingly aim for the superficial vascular plexus without involving the deep vascular plexus, and the infiltrating T cells bear a distinct phenotype expressing the cutaneous lymphocyte-associated antigen, which is recognized by mAb HECA-452. We wanted to know whether HECA-452+ lymphocytes indeed are able to distinguish between superficial and deep vascular plexus homing sites. Employing the hu-SCID mouse model grafted with human skin and human T cells, as described previously, we developed a new skin-grafting strategy providing superficial and deep vascular plexus skin specimens placed separately onto the same mouse. Fourteen days after allogeneic human T cell grafting, both human skin sites were densely infiltrated by human T cells, but only T cells within the superficial vascular plexus, but not within the deep vascular plexus, expressed the cutaneous lymphocyte-associated antigen. IL-2 and IFN-gamma expression and allogeneic vessel destruction were present within both superficial and deep vascular plexus skin. This model provides direct evidence that expression of a specific homing receptor is indeed able to direct lymphocyte traffic, not only to a distinct organ but also to a distinct vascular bed within one organ.

Animals↗
PubMed1997

Differences in tumor microvessel density between squamous cell carcinomas and basal cell carcinomas may relate to their different biologic behavior.

Tumor microvessel density (TMVD) has been recognized as an important indicator for the metastatic risk in certain tumors. The purpose of this study was to analyse whether there is an association of TMVD in epithelial neoplasms of the skin with their clinical behavior. Paraffin sections of keratoacanthomas (KA, n = 10), squamous cell carcinomas (SCC, n = 9), nodular (nod-BCC, n = 13), and sclerosing (scl-BCC, n = 12) basal cell carcinomas were immunohistochemically stained for factor-VIII-related antigen and TMVD was determined. In all SCC, KA and nod-BCC, TMVD significantly exceeded perilesional skin microvessel density (PSMVD) (SCC:TMVD/PSMVD = 20.54:11.25, p < 0.0001; KA:TMVD/PSMVD = 20.90:12.17, p < 0.0001; nod-BCC:TMVD/PSMVD = 16.77:13.34, p = 0.03). In contrast, no significant difference between TMVD and PSMVD was found in scl-BCC (15.44:12.86, p = 0.22). TMVD was significantly higher in SCC and KA compared to nod-BCC (p = 0.036 and 0.006, respectively). Our data demonstrate that SCC and KA are highly vascularized tumors. The fact that TMVD does not differ significantly between SCC and KA (p = 0.80) suggests that MVD is not an indicator for the metastatic risk or aggressive growth behavior of epithelial skin tumors. The finding that MVD in both nod- and scl-BCC is significantly lower than in SCC and KA, might at least in part explain the slow growth of BCC.

Biopsy↗
PubMed1996

Dermal microvascular endothelial cells express CD32 receptors in vivo and in vitro.

Immune complexes are thought to be the major cause of cutaneous necrotizing vasculitis, but the mechanism of immune complex targeting to specific vessels is largely unknown. In myelomonocytic cells, immune complex binding and receptor-mediated endocytosis are mediated by Fc gamma R. We asked whether dermal microvascular endothelial cells (DMEC) express Fc gamma Rs. In cryostat sections of normal human skin, mAb IV.3 or AT10, both recognizing CD32 (Fc gamma RII), localizes to the luminal surface of DMEC of the superficial but not of the deep vascular plexus. All DMEC do not express CD16 (Fc gamma RIII) or CD64 (Fc gamma RI) molecules. Adult skin-derived DMEC in culture express CD32 (Fc gamma RII) molecules, as measured by FACS, but are negative for CD16 or CD64. HUVEC, tested for comparison, do not express CD16, 32, or 64 proteins. By reverse-transcriptase PCR and subsequent Southern blot analysis, the isoform of the CD32 molecule expressed on DMEC is determined as Fc gamma RIIa. HUVEC do not contain Fc gamma RIIa or Fc gamma RIIb mRNA. In DMEC, Fc gamma RIIa cross-linking results in immediate intracellular free Ca2+ ([Ca2+]i) concentration fluxes and in rapid internalization of the occupied receptors. We conclude that DMEC are equipped with fully functional Fc gamma RIIa molecules.

Adult↗
PubMed1996

Human delayed-type hypersensitivity reaction in a SCID mouse engrafted with human T cells and autologous skin.

We have developed and animal model to study human delayed-type hypersensitivity reactions occurring in a human environment within a mouse host. Human skin was grafted onto the backs and autologous human immune cells were injected into the peritoneal cavity of mice with severe combined immunodeficiency. Seven and 14 d after grafting, 2-50% of total white blood and spleen cells were of human origin. Mouse spleen-derived human T cells from tetanus toxoid-sensitized donors proliferated in response to tetanus toxoid as measured by [3H]thymidine uptake, and the strength of this proliferative response equaled that with pre-graft T cells from the same donor. Proliferation was blocked with monoclonal antibodies to human but not to mouse major histocompatibility complex antigens and with anti-human CD4 monoclonal antibodies. In vivo vaccination of mice with tetanus toxoid did not enhance proliferation of mouse spleen-derived human T cells in response to antigen. Injection of tetanus toxoid into the human skin graft caused a perivascular human CD4+/CD25+ T-cell infiltrate, which was not present when tetanus toxoid was injected into adjacent mouse skin. We conclude that human T cells grafted into mice with severe combined immunodeficiency retain their function, that human T cells specifically recognize human but not mouse skin as homing sites, and that human T-cell responses depend on the human micro-environment. This model lends itself to studies of endothelium-T-cell interactions, T-cell activation within skin, and chronic inflammatory skin diseases.

Animals↗
PubMed1995

Contact-dependent endothelial class II HLA gene activation induced by NK cells is mediated by IFN-gamma-dependent and -independent mechanisms.

NK lymphocytes adhere avidly to allogeneic endothelial cells (ECs) and induce their membrane expression of MHC class II Ags in vitro. Endothelial class II expression augments EC-driven CD4+ T cell proliferation in vitro, and may amplify T cell recruitment and clonal expansion in vivo. Using an ex vivo lymphocyte-skin organ coculture model, NK cells could be found lining and inducing class II HLA on microvessel endothelium. Using neutralizing anti-IFN-gamma and anti-IFN-gamma receptor Abs, a spectrum of IFN-gamma dependence was observed for NK-mediated EC HLA-DR induction at the membrane and transcriptional levels, from negligible to moderate. Trans-well experiments displayed that direct NK-EC contact is required, and Ab inhibition studies indicated that the beta 2 integrin-ICAM-1 pathway(s) is critical in the generation of these responses. The use of HLA-DR alpha promoter constructs in transient transfection assays demonstrated that the highly conserved X and S transcription boxes are required in both IFN-gamma- and NK-mediated gene activation. As expected, because of the receptor species specificity, human IFN-gamma did not induce HLA-DR alpha promoter constructs transfected in Chinese hamster ovary cells, whereas NK cells did. Taken together, these results indicate that human allogeneic NK lymphocytes induce EC class II HLA gene activation and membrane expression in an adhesion-dependent, IFN-gamma-independent fashion and suggest that, in concert with any IFN-gamma-dependent component, this induction could represent an efficient mode of endothelial activation and immune amplification in vivo.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1995

IL-8 and angiogenesis: evidence that human endothelial cells lack receptors and do not respond to IL-8 in vitro.

It has been established that IL-8 triggers angiogenesis in vivo, but this effect may be mediated either by IL-8-recruited leukocytes or by direct actions of IL-8 upon endothelial cells (EC). We have approached this question by examining interactions of recombinant human IL-8 with cultured large vessel and microvascular human EC. We are unable to detect specific IL-8 binding to cultured human umbilical vein endothelial cells (HUVEC) or leukocyte-like IL-8 receptor mRNA expression by either cultured HUVEC or human dermal microvascular endothelial cells (DMEC). We find no alteration of cytoplasmic calcium concentration ([Ca2+]i) in either cell type in response to IL-8 treatment. Finally, we find no IL-8-induced change in EC proliferative rates in the presence or absence of endothelial cell growth factor. Our data favour an indirect action for IL-8 as an angiogenic factor.

Base Sequence↗
PubMed1994

Human T-cell-mediated destruction of allogeneic dermal microvessels in a severe combined immunodeficient mouse.

We developed a chimeric human-severe combined immunodeficient mouse model to study human allograft rejection. Mice received first partial thickness human skin grafts and then, after anastomosis of the mouse with graft human microvessels, human lymphocytes allogeneic to the skin. By 2 weeks, the skin grafts uniformly developed changes that resemble first-set skin rejection in humans. Vascular cell adhesion molecule 1 and major histocompatibility complex class II molecules were induced on the human vascular endothelium at day 6, prior to significant T-cell infiltration. Perivascular human CD4+ and CD8+ T-cell infiltrates were marked by day 11. Some T cells, adjacent to injured human vessels, expressed the cytolytic granule protein perforin. The human microvessels were destroyed by day 16 without significant damage to human keratinocytes or adjacent mouse microvessels. This small animal model may permit evaluation of potential therapeutic reagents that inhibit human T-cell-mediated injury.

Animals↗
PubMed1994

Inducibility and expression of microvascular endothelial adhesion molecules in lesional, perilesional, and uninvolved skin of psoriatic patients.

Previous studies have demonstrated 1) that patterns of inducible endothelial cell expression of endothelial leukocyte adhesion molecule-1 (ELAM-1) and vascular cell adhesion molecule-1 (VCAM-1) in response to cytokines varies both with anatomic position within the dermal microvasculature and with the presence of perivascular inflammatory infiltrates, and 2) that the anatomic architecture of the dermal superficial plexus (SVP) is altered in inflamed lesional but not in univolved skin of psoriatic patients. The present study was designed to evaluate the pattern of cytokine inducibility of ELAM-1 and VCAM-1 in altered dermal microvessels of psoriatic patients. At the light microscope level, preculture biopsies of uninvolved and perilesional skin were indistinguishable by morphology and ELAM-1 and VCAM-1 expression were virtually absent. In contrast, biopsied lesional skin showed elongated capillary loops and increased numbers of T cells compared to uninvolved and perilesional skin. The dermal microvasculature of the SVP of lesional skin contained ELAM-1+ in 29.4% of vessels and VCAM-1+ endothelial cells in 8.7% of vessels. After 24 h of organ culture in medium supplemented with tumor necrosis factor and interleukin-4, ELAM-1+ endothelial cells in the SVP were increased significantly in uninvolved (from mean 0.5% to 27% of vessels), perilesional (from mean 5.5% to 41.8% of vessels), and lesional skin (from mean 29.4% to 45.7% of vessels). VCAM-1 was not inducible on SVP endothelial cells in uninvolved skin but VCAM-1+ endothelial cells were increased significantly in perilesional (from mean 0.7% to 23.7% of vessels) and lesional skin (from mean 8.7% to 41.4% of vessels). In uninvolved and perilesional skin ELAM-1 and VCAM-1 were confined to endothelial cells below the rete. In contrast, endothelial cells of the intrapapillary part of the capillary loop of lesional skin became cytokine responsive, in that ELAM-1 and VCAM-1 could be induced at this site. By immunoelectron microscopy, expression was most intense on the luminal surface of venular endothelial cells and at the interendothelial junctions. In conclusion, we have presented evidence that the cytokine responsiveness of microvascular endothelial cells is altered in psoriasis in a pattern that may explain both the circumscribed nature and the epidermal involvement of the psoriatic plaque.

Adult↗
PubMed1993

Heterogeneity of dermal microvascular endothelial cell antigen expression and cytokine responsiveness in situ and in cell culture.

Microvascular endothelial cells (EC) recruit circulating leukocytes at sites of inflammation, in part through cytokine-regulated expression of endothelial-leukocyte adhesion molecules. Adhesion molecule expression varies among vascular beds and among EC within microvessels of a particular vascular bed. In the present study, we have examined the patterns of antigen expression and cytokine responsiveness of dermal microvascular endothelial cells (DMEC) in a skin organ culture model and, for comparison, in cell culture. Within the superficial vascular plexus (SVP) of normal skin, CD36 molecule expression is undetectable on capillary loops and is expressed on DMEC in only 20% of the larger, horizontal vessels. CD36 expression is not modulated by cytokines. Endothelial-leukocyte adhesion molecule-1 (ELAM-1) expression induced at 6 and 24 h by TNF or IL-1, is restricted to the venular side of the capillary loop and to the venules proper. Vascular cell adhesion molecule-1 (VCAM-1) expression is not inducible on EC of the SVP in normal skin by TNF, IL-1, or IL-4, alone or in combination at either time point. When inflamed skin is examined in organ culture, SVP EC are cytokine responsive regarding VCAM-1 expression. Within the deep vascular plexus (DVP). CD36 molecules are expressed on EC in all capillaries and small vessels. Both ELAM-1 and, to a lesser extent, VCAM-1 expression are inducible by TNF, IL-1, and/or IL-4 on capillaries and larger microvessels at 6 and 24 h. The larger vessels at the dermal-subcutaneous border were found to be CD36-/ELAM-1+/VCAM-1+ after cytokine treatment. CD36 expression of DMEC in cell culture varies from 47 to 98% of cells (mean 75%) in seven separate isolates and is not modified by cytokines. Upon TNF or IL-1 activation, 50 to 90% of DMEC express ELAM-1 molecules at 6 h and expression persists at high levels for 24 h. VCAM-1 expression is negligible at both times. These results with DMEC differ from human umbilical vein EC analyzed in parallel, which are completely CD36- and show transient ELAM-1 and sustained VCAM-1 expression in response to TNF and IL-1. In summary, we have demonstrated that DMEC comprise a heterogeneous population that differ from umbilical vein EC.

Animals↗
PubMed1993

CD68 positive epidermal dendritic cells.

In a pilot study designed to investigate immunopathologic events in the evolution of cutaneous lesions in pemphigus foliaceus, we found that in this condition the epidermis is replete with CD68+ dendritic cells. The present study was designed to investigate the nature of this novel intraepidermal CD68+ cell population. For that purpose lesional skin of five patients with PF and, for comparison, of patients with another acantholytic autoimmune disease, pemphigus vulgaris, were examined using a panel of monoclonal antibodies in a three-step immunoperoxidase technique, in an immunofluorescence double-labeling technique, and by immunoelectron microscopy. We found epidermal CD1a+ Langerhans cells significantly decreased in pemphigus foliaceus compared to pemphigus vulgaris, but pemphigus foliaceus and not pemphigus vulgaris epidermis harbored large amounts of bone marrow-derived (CD45+) cells that expressed CD68, HLA-DR, and beta 2-integrin antigens, the most pronounced expression being observed for CD11c and CD18. These epidermal CD68+ cells were of dendritic shape, were CD1a-, and lacked Birbeck granules (BG); however, a small portion of CD68+ cells was also CD1a+ and exhibited BG as revealed by immunoelectron microscopy. These findings demonstrate that in certain conditions, i.e., in pemphigus foliaceus but not in pemphigus vulgaris, there is a shift from CD1a+/CD68- epidermal Langerhans cells towards CD1a-/CD68+ dendritic epidermal cells. The detection of a small number of CD1a+/CD68+/BG+ dendritic epidermal cells may identify these cells as a link between the CD1a+/CD68+/BG+ Langerhans cells and the CD1a-/CD68+/BG- cell population and suggests that these cells represent a transitional form of myelomonocytic cells during their phenotypic and morphologic transformation into resident epidermal Langerhans cells.

Adolescent↗
PubMed1992

Severe sun sensitivity and the presence of antinuclear antibodies in patients with polymorphous light eruption-like lesions. A form fruste of photosensitive lupus erythematosus?

BACKGROUND: Initial lesions seen in some cases of lupus erythematosus may simulate the clinical features of polymorphous light eruption. OBJECTIVE: To evaluate the significance of antinuclear antibody screening in patients with polymorphous light eruption or to find better methods to define patients at risk to have lupus erythematosus, we analyzed the data of 198 patients with polymorphous light eruption. METHODS: History, type, and persistence of skin lesions were reviewed, and serologic variables, the minimal erythema dose, and the ultraviolet action spectrum for inducing skin lesions were determined. RESULTS: The morphologic features of skin lesions and results of phototesting were consistent with previously published characteristics of patients with polymorphous light eruption. Twenty-eight (14%) had high titers of antinuclear antibody (greater than or equal to 1:80). We found a highly significant correlation between severe sun sensitivity and the presence of high antinuclear antibody titers. Of these patients with severe sun sensitivity and high titers of antinuclear antibody, in three the diagnosis of systemic lupus erythematosus could be established according to American Rheumatism Association criteria. CONCLUSION: These results suggest that a combination of severe sun sensitivity and high titers of antinuclear antibody may characterize a subset of sun-sensitive patients with some features of lupus erythematosus.

Adult↗
PubMed1992

Necrobiosis lipoidica: treatment with systemic corticosteroids.

In an attempt to find an effective therapy for necrobiosis lipoidica, we have treated six patients with this disease with a 5-week course of systemic corticosteroids. This treatment resulted in complete cessation of disease activity in all patients and no recurrence in a mean follow-up period of 7 months; however, restitution of atrophic skin lesions could not be achieved. The therapy was well tolerated and did not pose problems, even in diabetic patients. These results strongly suggest that short-course therapy of necrobiosis lipoidica with corticosteroids is of lasting benefit to these patients and should probably be considered early in the course of their skin disease.

Administration, Oral↗
PubMed1992

Effects of cyclosporin A on resident and passenger immune cells of normal human skin and UV-induced erythema reactions.

Cyclosporin A (CyA) has proved effective in various dermatological diseases, but its mechanisms of action within the skin are still ill-defined. In order to characterize more clearly the cellular targets of CyA we examined its effects on skin immune cells in normal and UVB- and PUVA-irradiated skin by means of a three-step immunoperoxidase reaction and immunofluorescence double-labelling technique. The CyA-induced depletion of epidermal Langerhans cells equals that seen with UVB or PUVA alone. CyA alone has no effect on the number and distribution of dermal cells. CyA modulates the UV irradiation-induced changes by: (i) inhibiting the UVB- and PUVA-induced ICAM-1 expression by keratinocytes and (ii) suppressing the PUVA-induced upregulation of CD11a expression by macrophages (72 +/- 12% of Ki-M8+ macrophages express CD11a with PUVA, compared with 20 +/- 5% with CyA + PUVA, P < 0.001). Neither treatment affected ICAM-1 expression by endothelial cells. In addition, CyA increases PUVA minimal phototoxicity dose from 10 +/- 2.6 J/cm2 (PUVA alone) to 15.3 +/- 3.1 J/cm2 (CyA + PUVA), (P < 0.001). In conclusion, the effects of CyA on the skin include a down-modulation of the PUVA-erythema reaction, associated with a direct or indirect modulation of adhesion molecule expression.

Adult↗