Sialomucin CD43 regulates T helper type 17 cell intercellular adhesion molecule 1 dependent adhesion,apical migration and transendothelial migration

T helper type 17 lymphocytes (Th17 cells) infiltrate the central nervous system (CNS), induce inflammation and demyelination and play a pivotal role in the pathogenesis of multiple sclerosis. Sialomucin CD43 is highly expressed in Th17 cells and mediates adhesion to endothelial selectin (E-selectin), an initiating step in Th17 cell recruitment to sites of inflammation. CD43^−/− mice have impaired Th17 cell recruitment to the CNS and are protected from experimental autoimmune encephalomyelitis (EAE), the mouse model of multiple sclerosis. However, E-selectin is dispensable for the development of EAE, in contrast to intercellular and vascular cell adhesion molecules (ICAM-1 and VCAM-1). We report that CD43^−/− mice have decreased demyelination and T-cell infiltration, but similar up-regulation of ICAM-1 and VCAM-1 in the spinal cord, compared with wild-type (WT) mice, at the initiation of EAE. CD43^−/− Th17 cells have impaired adhesion to ICAM-1 under flow conditions in vitro, despite having similar expression of LFA-1, the main T-cell ligand for ICAM-1, as WT Th17 cells. Regardless of the route of integrin activation, CD43^−/− Th17 cell firm arrest on ICAM-1 was comparable to that of WT Th17 cells, but CD43^−/− Th17 cells failed to optimally apically migrate on immobilized ICAM-1-coated coverslips and endothelial cells, and to transmigrate under shear flow conditions in an ICAM-1-dependent manner. Collectively, these findings unveil novel roles for CD43, facilitating adhesion of Th17 cells to ICAM-1 and modulating apical and transendothelial migration, as mechanisms potentially responsible for Th17 cell recruitment to sites of inflammation such as the CNS.     

Intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression and function on cultured human glomerular epithelial cells.

Glomerular epithelial cells are involved in extracapillary inflammation (crescents) but the mechanisms of this extracapillary accumulation of macrophages, epithelial cells and occasional lymphocytes are unknown. Human glomerular parietal epithelial cells express ICAM-1 and VCAM-1 on immunohistological stains of renal biopsies. We studied the expression of these cell adhesion molecules on cultured human glomerular epithelial cells (HGEC), their regulation by pro-inflammatory cytokines, and their role in mediating the adhesion of concanavalin A (Con A)-activated peripheral blood mononuclear cells. Human glomerular epithelial cells in culture constitutively express ICAM-1 and VCAM-1. The expression of ICAM-1 was not significantly altered by tumour necrosis factor-alpha (TNF-alpha) (P = 0.32), IL-1 beta (P = 0.24), interferon-gamma (IFN-gamma) (P = 0.66) or IL-4 (P = 0.85). VCAM-1 expression was increased by all four cytokines, but only significantly so by IL-4 (P = 0.0001). Con A-stimulated, monocyte-depleted peripheral blood lymphocytes bound to human glomerular epithelial cells, median 28.9% (range 14.5-37.9%). This adherence was significantly inhibited by anti-ICAM-1 (P = 0.03) and anti-LFA-1 (P = 0.02), but not by anti-VCAM-1 (P = 0.13) or by antibody to von Willebrand factor (P = NS). The interaction between ICAM-1 on HGEC and LFA-1 on mononuclear cells may be important in the pathogenesis of extracapillary inflammation in glomerulonephritis.     

Ontogeny and induction of adhesion molecule expression in human fetal intestine.

In this study we examined the distribution of the adhesion molecules ICAM-1, VCAM-1 and E-selectin in human fetal intestine, to determine whether they may have a role in the development of gut-associated lymphoid tissue. Secondly, we studied the tempo of induction of these molecules after T cell activation in explants of human fetal intestine cultured in vitro. In the fetus from 11 to 20 weeks gestation, endothelial expression of ICAM-1 and diffuse staining of VCAM-1 was observed in the lamina propria. In contrast, there was intense expression of ICAM-1 and VCAM-1 in the developing Peyer's patches, suggesting that these molecules may be involved in the accumulation or organization of lymphoid tissue in the gut. After T cell activation in fetal intestinal explants, the expression of ICAM-1 and VCAM-1 was increased on most endothelial cells, leucocytes, and stromal cells in the lamina propria. Expression was maintained for at least 4 days. In contrast, the induction of E-selectin was rapid, and the expression was transient, despite the continuing presence of activated T cells and macrophages. This suggests that other factors are required to prevent the down-regulation of E-selectin to maintain the sustained expression sometimes observed in vivo.     

Expression of leucocyte–endothelial adhesion molecules is limited to intercellular adhesion molecule-1 (ICAM-1) in the lung of pneumoconiotic patients: role of tumour necrosis factor-alpha (TNF-α)

Coal workers' pneumoconiosis (CWP) is characterized by a chronic inflammatory lung reaction associated with macrophage accumulation in alveolar spaces. In this study, we investigated in CWP the implication of adhesion molecules such as E-selectin, ICAM-1 and vascular cell adhesion molecule-1 (VCAM-1) and the role of TNF-α which is one of the cytokines inducing their expression. Adhesion molecule expression was analysed by immunohistochemistry on lung biopsies from patients with CWP and from healthy subjects. In parallel, soluble adhesion molecules were detected in bronchoalveolar lavage fluids (BALF) from patients by specific ELISA. The involvement of TNF in the induction of these adhesion molecules was measured (i) by immunohistochemistry on sections from lung fragments, and (ii) by evaluating in vitro the expression of adhesion molecules on endothelial cells and on alveolar epithelial cells in the presence of alveolar macrophage supernatants. In control subjects, a weak staining of ICAM-1 was detected only in alveolar walls, while E-selectin and VCAM-1 were undetectable. In pneumoconiotic patients, ICAM-1 was expressed at a high level by endothelium, by alveolar and bronchial epithelial cells and by alveolar macrophages. E-selectin and VCAM-1 expression remained undetectable. Measurement of soluble adhesion molecule showed that only the concentration of sICAM-1 was significantly increased in BALF from patients with CWP compared with controls. The involvement of TNF in this ICAM-1 expression was shown by the in vitro effect of alveolar macrophage supernatants on adhesion molecule expresssion by endothelial cells and epithelial cells (this effect was neutralized by anti-TNF antibodies) and by the increased production of TNF in the lung of pneumoconiotic patients. These data provide evidence for the involvement of ICAM-1, induced at least in part by alveolar macrophage-derived TNF, in the development of the inflammatory reaction in CWP.     

Adhesion molecules (E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1)) in sera from patients with Staphylococcus aureus bacteraemia with or without endocarditis

The aim of this prospective study was to evaluate if patients with endocarditis display a more extensive endothelial activation than those with bacteraemia but without endocarditis. Sixty-five patients with blood culture-verified Staphylococcus aureus bacteraemia were included and serum samples collected on admission were analysed by enzyme immunoassays. Elevated serum concentrations of adhesion molecules were found in most of the patients with S. aureus bacteraemia. Patients with endocarditis (n = 15) showed significantly higher serum E-selectin (median 156 ng/ml) and VCAM-1 (median 1745 ng/ml) concentrations compared with those with S. aureus bacteraemia but without endocarditis (80 ng/ml and 1172 ng/ml, respectively; P = 0.01 and P = 0.003). No significant difference was found between the groups concerning ICAM-1 (median 451 ng/ml versus 522 ng/ml). In addition, serum tumour necrosis factor-alpha (TNF-alpha) concentrations were significantly correlated (P < 0.002) to serum levels of E-selectin, ICAM-1 and VCAM-1.     

Inhibition of endothelial cell adhesion molecule expression with SJC13, an azaindolidine derivative,in vitro

Stimulation of cultured human umbilical vein endothelial cells (HUVEC) with lipopolysaccharide (LPS) induces adherences for human promyelocytic cell line HL60. Adherence of HL60 cells to HUVEC stimulated with LPS for 4h was completely inhibited by pretreatment with SJC13, an azaindolidine derivative. The mechanism whereby SJC13 inhibits the adhesiveness of HUVEC was investigated. Pretreatment of SJC13 inhibited LPS-induced expression of E-selectin and vascular cell adhesion molecule-1 (VCAM-1), but not intercellular adhesion molecule-1 (ICAM-1), in HUVEC, determined by flow cytometry and cellular enzyme-linked immunosorbent assay (cell-ELISA). The inhibitory activity was concentration dependent between 62.5 and 1,000 g/ml. SJC13 also selectively inhibited LPS-induced increases in E-selectin and VACM-1 mRNAs, indicating that the action of SJC13 is to inhibit synthesis of these molecules. These data demonstrate that SJC13 is capable of selectively inhibiting the expression of E-selectin and VCAM-1, but not ICAM-1, in endothelial cells.accepted by I. Ahnfelt-Rønne     

The distribution of adhesion molecules in chronic periaortitis

Chronic periaortitis is a local complication of human atherosclerosis. It is defined as the triad of advanced atherosclerosis, medical thinning and aortic adventitial chronic inflammation. It is present to a variable degree in association with atherosclerotic abdominal aortic aneurysms. These aortic adventitial infiltrates differ from those described solely within the atheroma itself, in that they consist predominantly of B lymphocytes. Many of the lymphocytes are activated and proliferating, and germinal centres are common. In this study, an immunohistochemical analysis was carried out on fresh surgical aortic aneurysm tissue in order to investigate the presence and distribution of activation-inducible adhesion molecules, and to correlate this with the degree of inflammation. A consistent finding was the presence of E-selectin on endothelial cells in up to 50% of the vessels throughout the aortic wall and at the base of the atheroma, independent of the severity of inflammation. ICAM-1 expression was abundant on many cell types and increased with the severity of chronic inflammation, being strongest in the germinal centres. VCAM-1 expression was predominant on follicular dendritic cells and also increased with severity of inflammation. VCAM-1 expression was also detected on vessels within lymphoid follicles. The pattern of expression of the adhesion molecules suggests a role in the initiation and progression of chronic inflammation associated with advanced atherosclerosis.     

Expression of VCAM-1, ICAM-1, E- and P-selectin and tumour-associated macrophages in renal cell carcinoma

AIMS: Neoangiogenesis is accompanied by an increase in endothelial surface, which can support infiltration by immune cells depending on adhesion molecule expression. Therefore, the expression of cell adhesion molecules on microvessels and epithelial cells was analysed in renal cell carcinomas as compared to tumour-free tissue. METHODS AND RESULTS: PECAM-1, CD34, ICAM-1, VCAM-1, VLA-4, P- and E-selectin, the macrophage antigens Ki-M1P and Mac-1, and lymphocyte function antigen LFA-1 were identified immunohistochemically. VCAM-1, ICAM-1, and E-selectin were equally or less expressed, whereas P-selectin was increased on microvessels in tumour tissue. The density of VCAM-1-positive tumour microvessels correlated positively with an advanced tumour stage and E- and P-selectin-positive tumour microvessels with the amount of associated macrophages. The expression of ICAM-1 and VCAM-1 on neoplastic epithelia correlated with an increased density of macrophages and a minor degree of tumour differentiation. CONCLUSIONS: The positive correlation of macrophage infiltration and expression of cell adhesion molecules on tumour microvessels and epithelia with minor tumour differentiation and an advanced stage indicates that adhesion molecule expression is not associated with an effective antitumour function of macrophages     

Progress in computer-generated three-dimensional reconstruction

The expression of PECAM, ICAM-1, VCAM-1, and E-selectin was studied in 64 samples of human coronary arteries taken from 15 explanted hearts obtained within 5 min of transplantation. Normal artery (n=12), predominantly fibrous plaques (n=23), and plaques containing extracellular lipid (n=26) and three segments showing recanalization channels were studied. All endothelial cells strongly and equally expressed PECAM; positive staining was used to check that artefactual denudation of the endothelial surface had not occurred. PECAM was also present in some lipid-filled macrophages. Normal arteries showed no VCAM-1 staining but focal segments of the endothelium were positive for ICAM-1 and E-selectin. ICAM-1 was strongly and constantly expressed by the endothelium over all types of plaques and in macrophages. E-selectin expression was confined to endothelial cells and occurred on the surface in 35 per cent of fibrous and 22 per cent of lipid-containing plaques. VCAM-1 staining of surface endothelium occurred in 39 per cent of fibrous and 20 per cent of lipid-containing plaques. A population of spindle-shaped cells of macrophage type (positive for EMB11 antigen) expressed VCAM-1 in lipid-containing plaques. Adventitial vessels adjacent to plaques showed endothelial expression of ICAM-1 and E-selectin. VCAM-1 staining of adventitial vessel endothelium was associated with local lymphoid aggregation. In conclusion, the expression of cell adhesion molecules is an important element in the inflammatory component of atherosclerosis and contributes to both monocyte and lymphocyte activation and recruitment from advential vessels and the arterial lumen.     

Elevated expression in situ of selectin and immunoglobulin superfamily type adhesion molecules in retroocular connective tissues from patients with Graves' ophthalmopathy.

Activation of certain adhesion molecules within vascular endothelium and the surrounding extravascular space is a critical event in the recruitment and targeting of an inflammatory response or autoimmune attack to a particular tissue site. We have recently demonstrated that the adhesion of lymphocytes to cultured retroocular fibroblasts obtained from patients with Graves' ophthalmopathy (GO) is mediated predominantly by the interaction of lymphocyte function-associated antigen-1 (LFA-1), expressed on lymphocytes, with intercellular adhesion molecule-1 (ICAM-1), expressed by these cells following exposure to interferon-gamma (IFN-gamma), tumour necrosis factor-alpha (TNF-alpha), IL-1 alpha or purified thyroid-stimulating immunoglobulins. We now report the expression and localization in situ of several adhesion molecules, ICAM-1, endothelial leucocyte adhesion molecule-1 (ELAM-1), vascular cell adhesion molecule-1 (VCAM-1), and LFA-3 in retroocular tissues derived from patients with severe GO (n = 4) and normal individuals (n = 3). Serial cryostat sections of tissue specimens were processed for immunoperoxidase staining using various MoAbs against ICAM-1, ELAM-1, VCAM-1 and LFA-3. In addition, consecutive sections were stained with MoAbs against LFA-1, CD45RO (UCHL-1)DR-human leucocyte antigen (HLA-DR), CD11b/CD18 (Mac-1), and CD11c/CD18 (p150,95). In GO-retroocular tissues, strong immunoreactivity for ICAM-1 and LFA-3 was detected in blood vessels (> 90%), in perimysial fibroblasts surrounding extraocular muscle fibres, and in connective tissue distinct from extraocular muscle. No ICAM-1 or LFA-3 immunoreactivity was present in extraocular muscle cells themselves. ICAM-1 and LFA-3 immunoreactivity in normal tissues was minimal or absent both in connective and muscle tissues. Vascular endothelium was strongly positive for ELAM-1 and VCAM-1 in GO-retroocular tissues, while VCAM-1 immunoreactivity was minimal (< 5% of blood vessels) and ELAM-1 immunoreactivity was generally absent in normal retroocular tissue. LFA-1-expressing, activated mononuclear cells and memory T lymphocytes (CD3+/CD45RO+) were only detected in GO-retrocular tissues, and were mainly localized around blood vessels and in areas of ICAM-1-expressing connective and perimysial tissue. HLA-DR expression was restricted to GO-tissue specimens, with strong immunoreactivity detected in blood vessels, macrophages and connective tissue and perimysial fibroblasts. No HLA-DR was detectable in extraocular muscle cells. In conclusion, infiltration of the orbit in GO by mononuclear cells, and their targeting within the orbit, may depend upon the coordinate expression of certain adhesion and MHC molecules.(ABSTRACT TRUNCATED AT 400 WORDS)     

Circulating adhesion molecules in sarcoidosis.

Sarcoidosis is a disease of unknown etiology characterized by non-caseating granulomata together with a number of systemic abnormalities. We have recently shown these include increased expression of the integrins CD11/CD18 on peripheral blood leucocytes. Here we have measured serum levels of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1), E-selectin and vascular cell adhesion molecule-1 (VCAM-1) in 23 patients and 14 normal controls using antigen capture sandwich ELISAs. Median circulating E-selectin levels in the patients were nearly three times those of the controls (P < 0.0001, Mann-Whitney U-test), whilst ICAM-1 but not VCAM-1 levels were only slightly elevated. These results show that endothelial cell activation and shedding of E-selectin into the circulation are additional features of the pathology of sarcoidosis.     

Morphological aspects of LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways in human lymph nodes

Monoclonal antibodies specific for the adhesion molecules participating in lymphocyte homing, lymphocyte function associated antigen-1 (LFA-1) and very late antigen 4 (VLA4), and their respective ligands, intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1), were used to characterize their expression pattern in human lymph nodes by immunohistochemical and immunoelectron microscopic techniques. The location of LFA-1-positive lymphocytes and selective expression of ICAM-1 on the luminal plasma membrane of high endothelial venule endothelium suggested that the LFA-1/ICAM-1 adhesion pathway participates only in the initial step of the lymphocyte migration process. Lymphocytes passing through endothelium appear not to be influenced by this pathway. VCAM-1 was detected occasionally on the endothelium of high endothelial venules in the hyperplastic lymph nodes in the mesentery, but not in peripheral lymph nodes. VLA4-positive lymphocytes tended to be more frequently observed within high endothelial venules in mesenteric lymph nodes than in peripheral ones. Strong expression of both ligands, ICAM-1 and VCAM-1, was noted on the plasma membrane of follicular dendritic cells, and was especially prominent on their labyrinthine folding, and on the interdigitating cells in the paracortex. Furthermore, both LFA-1-and VLA4-positive lymphocytes localized around these cells. This suggests that LFA-1/ICAM-1 and VLA4/VCAM-1 adhesion pathways play an important role in the lymphocyte recognition of antigen-presenting cells.     

Biological function of CD40 on human endothelial cells: costimulation with CD40 ligand and interleukin-4 selectively induces expression of vascular cell adhesion molecule-1 and P-selectin resulting in preferential adhesion of lymphocytes

The expression of adhesion molecules on vascular endothelial cells determines the pattern of migration and extravasation of leucocytes in inflammation and immunity. Here we show that costimulation with CD40 ligand (CD40L) and interleukin (IL)-4 (or IL-13) gives rise to a unique pattern of adhesion molecule expression by human umbilical vein endothelial cells (HUVEC). CD40 ligation alone enhanced expression of vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1) and E-selectin whereas IL-4 and IL-13 increased expression of VCAM-1 and P-selectin but not ICAM-1 or E-selectin. When IL-4 and CD40L were combined there was an additional increase of both VCAM-1 and P-selectin, but ICAM-1 and E-selectin were both inhibited. The combined effects of IL-4 and CD40L signalling were not the result of altered response kinetics, enhanced sensitivity of the endothelium, or increased expression of CD40 or the IL-4 receptor. The rise in VCAM-1 expression induced by combined IL-4 and CD40L stimulation was slower and more sustained than with tumour necrosis factor-alpha (TNF-alpha) and occurred only on a subset (75-80%) of the endothelial cell population compared to 100% with TNF-alpha. Costimulation with IL-4 and CD40L increased adhesion of T cells and B cells above levels obtained with either signal alone, but decreased adhesion of neutrophils. Furthermore, CD40 and IL-4 synergistically increased IL-6 but decreased IL-8 production by HUVEC. These results show that interactions between IL-4 and CD40 on endothelial cells give rise to specific patterns of adhesion molecule expression and cytokine production that may have important implications for lymphocyte and neutrophil migration and function at sites of inflammation.     

Pirfenidone induces intercellular adhesion molecule-1 (ICAM-1) down-regulation on cultured human synovial fibroblasts

Pirfenidone has been shown to modify some cytokine regulatory actions and inhibit fibroblast biochemical reactions resulting in inhibition of proliferation and collagen matrix synthesis by fibroblast. We have investigated the effect of pirfenidone on the expression of cell adhesion molecules. The synovial fibroblasts were treated with IL-1α in the presence or absence of pirfenidone (range 0–1000 μM ), and assayed for the expression of adhesion molecules such as ICAM-1 and endothelial-leucocyte adhesion molecule-1 (E-selectin) by cell ELISA. Pirfenidone significantly down-regulated the expression of ICAM-1 on cultured synovial fibroblasts in a dose-dependent manner. In contrast, expression of E-selectin was not affected. Furthermore, we examined whether pirfenidone affects the cellular binding between cultured lymphocytes and IL-1α-stimulated synovial fibroblasts by in vitro binding assay and found their mutual binding was significantly suppressed in a dose-dependent manner by pirfenidone. It is speculated that down-regulation of ICAM-1 might be one of the novel mechanisms of action of pirfenidone. These data indicate a novel mechanism of action for pirfenidone to reduce the activation of synovial fibroblasts.     

Adhesion molecule expression in Graves'' thyroid glands; potential relevance of granule membrane protein (GMP-140) and intercellular adhesion molecule-1 (ICAM-1) in the homing and antigen presentation processes.

To assess the potential role of adhesion molecules in the pathogenesis of Graves' disease, we examined the expression of several of these adhesion molecules, including intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule (VCAM-1) and granule membrane protein-140 (GMP-140), in sections of Graves' thyroid glands and control thyroids, using immunohistochemical techniques. Up-regulated expression of GMP-140 was frequently observed on endothelial cells (EC) of post-capilliary venules in all Graves' thyroids examined, compared with an occasional weak staining on EC control glands. Some capillary EC around thyroid follicles (perifollicular EC) were strongly positive for GMP-140 in the Graves' thyroids in contrast to a negative staining on the same structures in the control glands. In addition, there was a correlation between the reactivity and frequency of GMP-140 expression on EC and the severity of mononuclear cell (MNC) infiltration in the Graves' thyroids. The expression of ICAM-1 was up-regulated on perifollicular EC and EC of small venules in some thyroids of both Graves' and control groups. Conversely, no significant expression was observed on any type of EC for both endothelial-leucocyte adhesion molecule-1 (ELAM-1) and VCAM-1. However, dendritic-like cells, present within lymphocytic infiltrates, were positive for VCAM-1 in most of the Graves' thyroids examined, especially in those with a severe lymphocytic infiltration. Thyrocytes were constantly negative for the expression of all four adhesion molecules investigated. These data suggest that GMP-140, as well as ICAM-1, could play an important role in the initiation of MNC infiltration in Graves' disease. ELAM-1 and VCAM-1 appear not to be relevant for the migration of MNC from the blood vessels into the target gland, although VCAM-1 expression on dendritic-like cells might play an additively tissue-selective role in autoantigen presentation and subsequent elicitation of autoimmune phenomena.     

Upregulation and co-localization of connexin43 and cellular adhesion molecules in inflammatory renal disease

Connexin43 (Cx43) is a major component of gap junctions. These are widely distributed in the human kidney and are thought to be involved in the inflammatory response and in the regulation of cell growth. Cellular adhesion molecules (CAMs) are also thought to be important in these processes, where they possibly facilitate gap junction formation. The aims of the current study were to define for the first time the expression of Cx43 in inflammatory glomerulonephritis and to compare the localization of this connexin with that of the intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and E-selectin. Human renal biopsies and control sections of normal human kidney were stained using the alkaline phosphatase/anti-alkaline phosphatase immunohistochemical technique, demonstrating that Cx43 was strongly expressed on inflammatory cells, on damaged tubular cells, and on interstitial cells. This pattern of expression was paralleled closely by that of ICAM-1 and, to a lesser extent, by that of VCAM-1. Cx43 is therefore primarily implicated in tubulointerstitial inflammation.© 1997 John Wiley & Sons, Ltd.     

Expression of adhesion molecules in human intestinal graft-versus-host disease.

The distribution of three cellular adhesion molecules, ICAM-1, ELAM-1 and VCAM-1, was studied in normal rectal mucosa and in graft-versus-host disease (GvHD) using immunohistological and morphometric techniques. In normal controls, ICAM-1 was demonstrable on endothelial cells and leucocytes within the lamina propria, ELAM-1 on endothelial cells only and VCAM-1 on lamina propria leucocytes, many of which exhibited long dendritic processes surrounding the glands. In GvHD, the enterocytes became positive for ICAM-1 and this was often associated with the presence of intra-epithelial LFA-1+ lymphocytes and macrophages, the latter containing debris of apoptotic cells. The staining was, however, restricted to the luminal membrane of the epithelial cells, raising doubts about the role of ICAM-1 as a ligand for LFA-1 on mucosal leucocytes in rectal GvHD. ELAM-1 expression was increased in GvHD both in terms of the length of positive endothelium and staining intensity. VACM-1 was increased on endothelial cells but not leucocytes in the lamina propria in contrast to our previous findings in cutaneous GvHD where VCAM-1+ dendritic cells were increased and endothelial cells remained negative. Normal patterns of adhesion molecule staining were seen in two biopsies exhibiting no morphological evidence of GvHD, from patients who had strong clinical evidence of the disease, indicating that immunostaining for these molecules is unlikely to be of help in improving the sensitivity of histological diagnosis. However, the possibility that adhesion molecule staining may be useful in improving diagnostic specificity by helping to distinguish GvHD from identical histological changes produced by irradiation and cytotoxic drugs is worthy of further investigation.     

The immunosuppressive drug mycophenolate mofetil impairs the adhesion capacity of gastrointestinal tumour cells

Immunosuppression correlates with the development and recurrence of cancer. Mycophenolate mofetil (MMF) has been shown to reduce adhesion molecule expression and leucocyte recruitment into the donor organ. We have hypothesized that MMF might also prevent receptor-dependent tumour dissemination. Therefore, we have investigated the effects of MMF on tumour cell adhesion to human umbilical vein endothelial cells (HUVEC) and compared them with the effects on T cell-endothelial cell interactions. Influence of MMF on cellular adhesion to HUVEC was analysed using isolated CD4+ and CD8+ T cells, or WiDr colon adenocarcinoma cells as the model tumour. HUVEC receptors ICAM-1, VCAM-1, E-selectin and P-selectin were detected by flow cytometry, Western blot or Northern blot analysis. Binding activity of T cells or WiDr cells in the presence of MMF were measured using immobilized receptor globulin chimeras. MMF potently blocked both T cell and WiDr cell binding to endothelium by 80%. Surface expression of the endothelial cell receptors was reduced by MMF in a dose-dependent manner. E-selectin mRNA was concurrently reduced with a maximum effect at 1 microm. Interestingly, MMF acted differently on T cells and WiDr cells. Maximum efficacy of MMF was reached at 10 and 1 microm, respectively. Furthermore, MMF specifically suppressed T cell attachment to ICAM-1, VCAM-1 and P-selectin. In contrast, MMF prevented WiDr cell attachment to E-selectin. In conclusion, our data reveal distinct effects of MMF on both T cell adhesion and tumour cell adhesion to endothelial cells. This suggests that MMF not only interferes with the invasion of alloactivated T cells, but might also be of value in managing post-transplantation malignancy.     

Interaction of endothelial cells and neutrophils in vitro: kinetics of thrombomodulin, intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular cell adhesion molecule-1 (VCAM-1): implications for the relevance as serological disease activity markers in vasculitides

Recently markers of endothelial cell activation or injury gained increasing interest as serological parameters of disease activation in vasculitides. Among these, soluble serum thrombomodulin, ICAM-1, VCAM-1 and E-selectin are of particular interest. However, only thrombomodulin showed the expected close correlation. The objective of this study was to investigate in vitro the kinetics of these endothelial cell receptors after interaction of unstimulated or cytokine-activated polymorphonuclear neutrophils (PMN) and endothelial cells in order to find evidence explaining these different clinical findings. Over the time period of up to 48 h of incubation the kinetics of thrombomodulin, ICAM-1, E-selectin, and VCAM-1 levels in the supernatant of endothelial cells in co-culture with neutrophils were determined in vitro by ELISA under basal and partially cytokine-activated (tumour necrosis factor-alpha) conditions. Increased levels of ICAM-1, E-selectin and VCAM-1 were already found due to cytokine activation of endothelial cells alone. This increase was augmented after coincubation with neutrophils. In contrast, a significant increase of thrombomodulin in the supernatant was only found due to cell injury after cell-cell interaction of cytokine-activated endothelial cells with neutrophils. In conclusion, this in vitro model of the kinetics of soluble endothelial cell receptors after cell-cell interaction of cytokine-activated PMN and endothelial cells underlines the advantage of thrombomodulin in contrast to the adhesion molecules as a marker of endothelial damage. Therefore, soluble thrombomodulin seems to be a promising, valuable serological disease activity marker in vasculitides.     

Expression and cell distribution of the intercellular adhesion molecule, vascular cell adhesion molecule, endothelial leukocyte adhesion molecule, and endothelial cell adhesion molecule (CD31) in reactive human lymph nodes and in Hodgkin''s disease.

The immunocytochemical expression of intercellular adhesion molecule (ICAM-1), vascular cell adhesion molecule (VCAM-1), endothelial leukocyte adhesion molecule (ELAM-1), endothelial cell adhesion molecule (EndoCAM CD31), and HLA-DR antigens was investigated in sections of 24 reactive lymph nodes and in 15 cases of Hodgkin's disease. ICAM-1 was detected in sinus macrophages, follicular dendritic reticulum cells (FDRCs), interdigitating reticulum cells (IDRCs), epithelioid macrophages, Hodgkin's cells (HCs), and vascular endothelium. ICAM-1 expression was often associated with that of HLA-DR antigens. VCAM-1 was detected in FDRCs, in fibroblast reticulum cells (FRCs), in macrophages, and in rare blood vessels. EndoCAM (CD31) was constitutively expressed in all types of endothelial cells, sinus macrophages, and in epithelioid granulomas. ELAM-1 was selectively expressed by activated endothelial cells of high endothelium venules (HEVs). When expression of the inducible adhesion molecules ICAM-1, VCAM-1 and ELAM-1 was comparatively evaluated in HEVs, it was found that ICAM-1 + HEVs were present in all reactive and HD nodes, whereas ELAM-1 and/or VCAM-1 were expressed only in those pathologic conditions characterized by high levels of interleukin-1/tumor necrosis factor (IL-1/TNF) production, such as granulomatosis and Hodgkin's disease. In Hodgkin's disease, the expression of ELAM-1/VCAM-1 was more pronounced in cases of nodular sclerosis and was associated with a significantly higher content of perivascular neutrophils.