Human papillomavirus-16-E7 oncoprotein enhances the expression of adhesion molecules in cervical endothelial cells but not in human umbilical vein endothelial cells.

OBJECTIVES: E7 is one of the oncoproteins encoded by human papillomavirus-16 (HPV-16), the major etiologic factor responsible for cervical cancer. Human papillomavirus-16-E7 expressed by human uterine cervix carcinoma cells is also released in the extracellular compartment where it induces immune suppression. We investigated whether E7 was also responsible for the enhanced endothelial adhesiveness required in cancer progression. STUDY DESIGN/METHODS: We treated cervical microvascular endothelial cells (CrMVEn) and human umbilical vein endothelial cells (HUVEC) with E7, tumor necrosis factor-alpha (TNF-alpha), and hydrogen peroxide (H2O2) and measured the expression of E-selectin, intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) by fluorescent-activated cell sorter analysis. RESULTS: E7 strongly induced the expression of E-selectin, ICAM-1, and VCAM-1 in CrMVEn, but not in HUVEC. Tumor necrosis factor-alpha further increased the endothelial expression of adhesion molecules in CrMVEn. Hydrogen peroxide pre-treatment resulted in an enhanced ICAM-1 and a decreased E-selectin and VCAM-1 expression. We also show indirect effects when endothelial cells were stimulated with the supernatant of E7-pretreated macrophages. CONCLUSIONS: These results show that HPV-16-E7 oncoprotein strongly induces adhesion molecules expression in organ-specific endothelial cells.     

Differential influences of bFGF and VEGF on the expression of vascular cell adhesion molecule-1 on human umbilical vein endothelial cells]

A fundamental feature of inflammation includes angiogenesis, adhesion of leukocytes to vascular endothelium, and entry of leukocytes into inflamed tissues. Recent studies have suggested that angiogenesis and cellular adhesion may be mutually linked processes. Both basic fibroblast growth factor (bFGF) and vascular endothelial growth factor (VEGF) have been shown to facilitate angiogenesis. However, their roles in the expression of adhesion molecules on the endothelial cells have not been clarified. The current studies therefore examined the effect of bFGF and VEGF on the expression of vascular cell adhesion molecule-1 (VCAM-1) on human umbilical vein endothelial cells (HUVEC) stimulated with tumor necrosis factor alpha (TNF-alpha). HUVEC (1 x 10(4)/well) were incubated in a 96 well microtiter plate with culture medium containing endothelial cell growth supplement (ECGS) for 24 h. After the incubation, culture medium was replaced by ECGS free culture medium with or without TNF-alpha (10 ng/ml), bFGF (10 ng/ml) and VEGF (10 ng/ml), and the culture was further carried out for additional 24 h. The expression of VCAM-1, E-selectin, and intercellular adhesion molecule-1 (ICAM-1) was measured by cell ELISA and the proliferation of HUVEC was measured by MTT colorimetric assay. Soluble VCAM-1 (sVCAM-1) in the supernatants were assessed by ELISA. Although, both bFGF and VEGF supported the proliferation of HUVEC, bFGF, but not VEGF, selectively suppressed the expression of VCAM-1 on HUVEC stimulated with TNF-alpha. The expression of ICAM-1 and E-selectin induced by TNF-alpha was not inhibited by either bFGF or VEGF. In addition, bFGF also decreased the levels of sVCAM-1 in the supernatants of TNF-alpha stimulated HUVEC. The data indicate that bFGF, but not VEGF, suppresses the production of VCAM-1 by HUVEC under stimulation with TNF-alpha. These results therefore suggest that angiogenic cytokines bFGF and VEGF play different roles in the regulation of the expression of adhesion molecules on endothelial cells under inflammation.     

Increased adhesion of human monocytes to IL-4-stimulated human venous endothelial cells via CD11/CD18, and very late antigen-4 (VLA-4)/vascular cell adhesion molecule-1 (VCAM-1)-dependent mechanisms.

Expression of adhesion molecules on endothelial cells (EC) can be up-regulated or induced by cytokines. The aim of the present study was to investigate the effect of IL-4 on both the expression of adhesion molecules on EC and monocyte adhesion to EC. Flow cytometric analysis showed that VCAM-1 expression on EC was up-regulated after stimulation with IL-4 for 24 h, whereas the expression of E-selectin (formerly called endothelial leucocyte adhesion molecule-1 (ELAM-1)) was not enhanced, and that of intercellular adhesion molecule-1 (ICAM-1) only slightly. The adhesion of monocytes to EC increased to maximum values upon stimulation of EC with IL-4 for 24 h. Coating of monocytes with MoAb against the integrin beta 2-subunit (CD18) significantly inhibited their adhesion to IL-4-stimulated EC; maximal inhibition was found when monocytes were coated with anti-CD18 MoAb in combination with MoAb against CD49d (the alpha-chain of VLA-4), whereas no inhibition was found when monocytes were coated only with MoAb against CD49d. Monocyte adhesion was not significantly inhibited when IL-4-stimulated EC were coated with MoAbs against ICAM-1 or VCAM-1 alone or in combination. Adhesion of monocytes was inhibited to a greater extent when in addition to coating of monocytes with MoAb against CD18 the EC were coated with MoAb against VCAM-1. From these results we conclude that monocytes bind to IL-4-stimulated EC via interaction of CD11/CD18 molecules on the monocytes with an as yet unknown endothelial ligand, and interaction of VLA-4 on monocytes with VCAM-1 on EC.     

Effect of ultraviolet light on the expression of adhesion molecules and T lymphocyte adhesion to human dermal microvascular endothelial cells

In order to determine the effect of ultraviolet radiation (UVR) on the cell adhesion molecules expressed in human dermal microvascular endothelial cells (HDMEC), the cells were exposed to varying UVR doses and the cell surface was examined for expression of intercellular cell adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM- 1), and E-selectin. The effect of UVB irradiation on the binding of T lymphocytes to HDMEC was also examined. UVA irradiation did not affect the surface expression of ICAM-1, VCAM-1, or E-selectin on the HDMEC. However, following UVB exposure, ELISA demonstrated a significant increase in the baseline ICAM-1 cell surface expression on the HDMEC. However, no induction of either E-selectin or VCAM-1 was noted. UVB also significantly augmented ICAM-1 induction by IL-1alpha and TNF-alpha. VCAM-1 was induced by stimulating HDMEC with IL-1alpha following a UVB irradiation dose of 100 mJ/cm2. Flow cytometric analysis of the HDMEC stimulated with IL-1alpha for 24h demonstrated that 12% of the cells expressed VCAM-1 but either IL-1alpha or UVB irradiation alone failed to induce VCAM-1 expression. Enhancement of T cell-HDMEC binding by IL-1alpha or TNF-alpha treatment was not significantly affected after UVB irradiation. This study demonstrated that UVB irradiation can alter ICAM-1 and VCAM-1 expression on the HDMEC surface and that augmentation of ICAM-1 expression and the IL-1alpha-dependent induction of VCAM-1 following UVB exposure might be important steps in the pathogenesis of sunburn.     

轻度修饰低密度脂蛋白对血管内皮细胞粘附功能影响及其机理初探

目的:观察轻度修饰LDL(MM-LDL)对培养人脐静脉内皮细胞(HUVEC)与人类单核细胞系U937粘附功能及其表面粘附分子表达的影响。方法:利用计数法观察经MM-LDL作用的HUVEC与U937细胞的粘附率;用ELISA方法检测MM-LDL作用后HUVEC膜表面粘附分子血管细胞粘附分子-1(VCAM-1)、细胞间粘附分子-1(ICAM-1)及P选择素(P-selectin)的表达。结果:MM-LDL(75mg/L)作用HUVEC4h后,其对U937细胞粘附率明显增加(P<0.01),HUVEC膜表面未见VCAM-1,ICAM-1,P-selectin表达上调,作为阳性对照重组肿瘤坏死因子α(rTNF_α)5.0μg/L可显著诱导以上3种粘附分子表达。延长MM-LDL与HUVEC作用时间至18h可诱导产生P-selectin表达,对VCAM-1表达无影响。结论:MM-LDL诱导的HUVEC与U937粘附不是通过ICAM-1、VCAM-1介导的,P-selectin可能起一定的作用。     

Leucocyte Endothelial Cell Adhesion: a Study comparing Human Umbilical Vein Endothelial Cells and the Endothelial Cell Line EA-hy-926

EA-hy-926 is a cell line produced by hybridizing human umbilical vein endothelial cells (HUVEC) and the epithelial cell line A549. To establish whether EA-hy-926 could be used as a model for endothelial cells (EC) in leucocyte-EC adhesion interactions, the effect of interleukin-4 (IL-4), tumour necrosis factor (TNF) or interferon-γ (IFN) stimulation on their adhesiveness and expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and intercellular adhesion molecule-1 (ICAM-1) was compared with that of HUVEC and A549. Although HUVEC exhibited increased adhesiveness and adhesion molecule expression with IL-4, TNF or IFN, EA-hy-926 exhibited these responses only with TNF. CD11/CD 18-dependent binding accounted for a significant component of basal binding to HUVEC and EA-hy-926, but did not account for the increased binding of T cells, JY, J6, ICH-BJ or ICH-KM cell lines to TNF-stimulated monolayers. At least part of the CD1l/CD18-independent adhesion was attributable to VCAM-1 induction on HUVFC and FA-hy-926. TNF-stimulation also induced F-selectin expression on EA-hy-926 and HUVEC and an accompanying increase in neutrophil (PMN) binding. The EA-hy-926 cells used in this study, therefore, showed responses similar to HUVEC when stimulated with TNF but not when stimulated with IL-4 or IFN.     

IL-6 acts on endothelial cells to preferentially increase their adherence for lymphocytes

Using a quantitative monolayer adhesion assay, the current report shows that treatment of human umbilical vein endothelial cells (HUVEC) with IL-6 increases their adhesiveness for blood lymphocytes, particularly CD4⁺ cells, but not for polymorphonuclear cells and monocytes. This effect, which was most pronounced when using low concentrations of the cytokine (0.1–1.0 U/ml) and a short incubation period (4 h), was also apparent with microvascular endothelial cells and a hybrid endothelial cell line. Skin lesions from patients with mycosis fungoides contain high levels of IL-6, and blood lymphocytes from patients with this disorder also exhibited an enhanced adhesion to IL-6-treated HUVEC. The cytokine enhanced intercellular adhesion molecule-1 (ICAM-1) expression and induced the expression of vascular cell adhesion molecule-1 (VCAM-1) and E-selectin on endothelial cells. Antibody blocking studies demonstrated that the vascular adhesion molecules ICAM-1, VCAM-1 and E-selectin and the leucocyte integrin LFA-1 all contributed to lymphocyte binding to endothelium activated by IL-6. It is proposed that IL-6 may be involved in the recruitment of lymphocytes into non-lymphoid tissue.     

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.     

Expression of ICAM-1, VCAM-1, E-selectin and TNF-alpha on the endothelium of femoral and iliac arteries in thromboangiitis obliterans

Immunohistochemical light and electron microscopical analysis of surgical biopsies obtained from femoral and iliac arteries of patients with thromboangiitis obliterans (TAO) were performed to investigate the presence of tumour necrosis factor-alpha (TNF-alpha) and expression of the endothelial cell adhesion molecules intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin. Expression of ICAM-1, VCAM-1 and E-selectin was increased on endothelium and some inflammatory cells in the thickened intima in all TAO patients. Ultrastructural immunohistochemistry revealed contacts between mononuclear blood cells and ICAM-1-, and E-selectin-positive endothelial cells. These endothelial cells showed morphological signs of activation. The present data indicate that endothelial cells are activated in TAO and that vascular lesions are associated with TNF-alpha secretion by tissue-infiltrating inflammatory cells, ICAM-1-, VCAM-1- and E-selectin expression on endothelial cells and leukocyte adhesion via their ligands. The preferential expression of inducible adhesion molecules in microvessels and mononuclear inflammatory cells suggests that angiogenesis contributes to the persistence of the inflammatory process in TAO.     

Biocompatibility evaluation of surface-treated AISI 316L austenitic stainless steel in human cell cultures

The effects of AISI 316L austenitic stainless steel, tested in untreated state or subjected to glow-discharge nitriding (at 10 or 20 hPa) and nitriding + post-oxidizing treatments, on human umbilical vein endothelial cells (HUVEC) and on peripheral blood mononuclear cells (PBMC) were evaluated. All the treated samples showed a better corrosion resistance in PBS and higher surface hardness in comparison with the untreated alloy. In HUVEC put in contact for 72 h with the sample types, proliferation and apoptosis decreased and increased, respectively, in the presence of the nitrided + post-oxidized samples, while only slight differences in cytokine (TNF-alpha, IL-6, and TGF-beta1) release were registered. Intercellular adhesion molecule-1 (ICAM-1) increased in HUVEC incubated with all the treated samples, while vascular cell adhesion molecule-1 (VCAM-1) and E-selectin increased in the presence of all the sample types. PBMC incubated for 48 h with the samples showed a decrease in proliferation and an increase in apoptosis in the presence of the untreated samples and the nitrided + post-oxidized ones. All the sample types induced a remarkable increase in TNF-alpha and IL-6 release in PBMC culture medium, while only the untreated sample and the nitrided at 10 hPa induced an increase in ICAM-1 expression. In HUVEC cocultured with PBMC, previously put in contact with the treated AISI 316L samples, increased levels of ICAM-1 were detected. In HUVEC coincubated with the culture medium of PBMC, previously put in contact with the samples under study, a noteworthy increase in ICAM-1, VCAM-1, and E-selectin levels was always registered, with the exception of VCAM-1, which was not affected by the untreated sample. In conclusion, even if the treated samples do not show a marked increase in biocompatibility in comparison with the untreated alloy, their higher corrosion resistance may suggest a better performance as the contact with physiological environment becomes longer.     

Effects of plasma treated PET and PTFE on expression of adhesion molecules by human endothelial cells in vitro

The aim of this study was to evaluate the expression of adhesion molecules on the surface of human endothelial cells in response to the systematic variation in materials properties by the ammonia plasma modification of polyethylene terephthalate (PET) and polytetrafluorethylene (PTFE). These adhesion molecules act as mediators of cell adhesion, play a role in the modulation of cell adhesion on biomaterials and therefore condition the response of tissues to implants. First and second passage human umbilical vein endothelial cells (HUVECs) were cultured on plasma treated and untreated PET and PTFE. HUVECs grown on polystyrene tissue culture coverslips and HUVECs stimulated with tumour necrosis factor (TNF-alpha) were used as controls. After 1 day and 7 days, the expression of adhesion molecules platelet endothelial cell adhesion molecule-1 (PECAM-1), intercellular adhesion molecule-1 (ICAM-1), Integrin alphavbeta3, vascular cell adhesion molecule-1 (VCAM-1), E-selectin, P-selectin and L-selectin were evaluated using flow cytometry and immunohistochemistry. There was a slight increase in positive cell numbers expressing the adhesion molecules ICAM-1 and VCAM-1 on plasma treated PET and PTFE. A significant increase in E-selectin positive cells on untreated PTFE was demonstrated after 7 days. Stimulation with TNF-alpha demonstrated a significant increase in the proportion of ICAM-1. VCAM-1 and E-selectin positive cells. Almost all cells expressed PECAM-1 and integrin alphavbeta3, on both materials and controls but did not express P- and L-selectin on any surface. When second passage cells were used, the expression of the adhesion molecules ICAM-1 and VCAM-1 was markedly increased on all surfaces but not with TNF-alpha. These significant differences were not observed in other adhesion molecules. These results were supported by immunohistochemical studies. The effects of plasma treated PET and PTFE on cell adhesion and proliferation was also studied. There was a 1.3-fold increase in cell numbers adhered on ammonia plasma treated PET compared to untreated PET and a 5.5-fold increase in cell numbers on treated PTFE compared to untreated PTFE after 1 day. This is significantly different when analysed statistically. After 7 days, cell number increased significantly on all surfaces compared to 1 day, except for untreated PTFE which conversely reduced by 41%. Cell number on the surface of untreated PET was no different to treated PET on days 1 and 7 when second passage cells were used. The study has shown that the plasma treatment of PET and PTFE with ammonia improves the adhesion and growth of endothelial cells and slightly upregulates the expression of adhesion molecules. This surface modification should promote colonisation of an artificial vascular prosthesis by endothelial cells and make it less vulnerable to immune system cells of the recipient. In addition, it should be considered which passage of cells is used due to the different adhesion features of different passages of HUVECs on untreated PET.     

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     

Direct interaction with primed CD4+ CD45R0+ memory T lymphocytes induces expression of endothelial leukocyte adhesion molecule-1 and vascular cell adhesion molecule-1 on the surface of vascular endothelial cells.

The process of recruitment of leukocytes at sites of inflammation involves direct cell-to-cell interactions between leukocytes and vascular endothelial cells (EC) mediated by various adhesion receptors on leukocytes and their inducible endothelial ligands. In this study we have examined the induction on EC of endothelial leukocyte adhesion molecule-1 (ELAM-1), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) upon their interaction with subpopulations of human T cells. When co-cultured with EC both resting CD4+ T and CD8+ T cells caused a modest increase in the expression of endothelial ICAM-1. Moreover, resting CD4+ but not CD8+ T cells induced expression of ELAM-1 and VCAM-1 on a small fraction of unstimulated EC. Prior activation with phorbol 12-myristate 13-acetate (PMA) significantly increased the ability of T cells to up-regulate endothelial ICAM-1 and also induced the expression of both ELAM-1 and VCAM-1. PMA-primed CD4+ T cells induced both VCAM-1 and ELAM-1 on EC more efficiently than CD8+ T cells. Furthermore, the ability to induce the expression of ELAM-1 and VCAM-1 was confined to the CD4+ CD45R0+ memory/primed subpopulation of T cells. This induction of various endothelial adhesion ligands could also be mediated by antigen-primed CD4+ T cell lines. The CD4+ T cell-mediated induction of adhesion ligands required direct intercellular contact with EC because neither cultures of EC and PMA-primed CD4+ T cells separated by a microporous membrane insert nor the conditioned medium of PMA-primed T cells induced expression of ELAM-1 and VCAM-1 on EC. Cyclosporin A significantly inhibited the activation of T cells with PMA but had no effect on the ability of PMA-primed T cells to up-regulate endothelial CAM. Thus, CD4+CD45R0+ T cells via as yet unknown mechanism can significantly enhance the expression of each of the three endothelial adhesion ligands and, thereby, may facilitate the process of recruitment of additional leukocytes to exacerbate inflammation.     

CELL ADHESION MOLECULE EXPRESSION WITHIN HUMAN GLOMERULAR AND KIDNEY ORGAN CULTURE

A glomerular and kidney organ culture method was developed to study cytokine inducibility of adhesion molecules and MHC antigen expression. Glomerular cells showed constitutive expression of intercellular cell adhesion molecule-1 (ICAM-1) and MHC class I and II antigens, but not vascular cell adhesion molecule-1 (VCAM-1), E-selectin, or P-selectin. Expression of E-selectin on glomerular endothelial cells (ECs) was induced by interleukin-1 (IL-1), tumour necrosis factor (TNF), interferon-γ (IFN-γ) and granulocyte/macrophage-colony stimulating factor (GM-CSF); this induction was inhibited by transforming growth factor beta (TGFβ) and by IL-4. P-selectin expression was never seen within glomeruli. VCAM-1 was constitutively expressed by Bowman's capsule and proximal tubules and was weakly induced on glomerular ECs by TNF and IL-4 in combination. Glomerular endothelial ICAM-1 expression was increased by IL-1, TNF, IFN-γ, and GM-CSF, while TGFβ inhibited induction by TNF and IL-1. Expression of MHC class I and II antigens by glomerular ECs was constitutive; further upregulation of MHC class II by IFN-γ was observed. These studies suggest that leukocyte–endothelial cell interactions that occur within the kidney follow broadly similar principles as are proposed to occur elsewhere in the body but, in addition, there are subtle differences that reflect local conditions. © 1997 by John Wiley & Sons, Ltd.     

补肾宁心方对人单核-血管内皮细胞粘附的影响

目的:探讨补肾宁心方对人单核-血管内皮细胞粘附的影响及机理。方法:以培养人脐静脉内皮细胞(HUVECs)作为靶细胞,在内皮细胞培养基中加入氧化的低密度脂蛋白(ox-LDL)或在试验体系中加入灌服补肾宁心方的兔血清,以孟加拉玫瑰红活细胞染色法测定人单核细胞系U937与HUVECs的粘附,并用流式细胞仪检测内皮细胞表面粘附分子细胞间粘附分子-1(ICAM-1)、血管细胞粘附分子-1(VCAM-1)以及E-选择素的表达。结果:ox-LDL显著增强单核U937细胞与内皮细胞之间的相互粘附,如在试验体系中加入灌服补肾宁心方的动物血清,则粘附率明显降低(P＜0.01)。流式细胞仪分析结果显示ox-LDL能明显促进内皮细胞表面ICAM-1、VCAM-1以及E-选择素的表达,补肾宁心方中药灌服血清可显著下调内皮细胞表面ICAM-1、VCAM-1以及E-选择素的表达(P＜0.01)。结论:补肾宁心方含药血清可能通过下调内皮细胞表面粘附分子的表达抑制单核-血管内皮细胞粘附,从而发挥对血管内皮细胞的保护作用。     

Importance of IFN-gamma-mediated expression of endothelial VCAM-1 on recruitment of CD8+ T cells into the brain during chronic infection with Toxoplasma gondii.

Interferon-gamma (IFNgamma) is essential for preventing reactivation of chronic infection with Toxoplasma gondii in the brain. We examined the role of IFNgamma on lymphocyte and endothelial adhesion molecule expression and T cell recruitment into the brain during chronic infection with T. gondii in IFNgamma knockout (IFNgamma(-/-)) and wild-type (WT) mice. Although the number of cerebral vessels expressing intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) increased in both WT and IFNgamma(-/-) mice following infection, there were more VCAM-1(+) vessels in brains of infected WT than of infected IFNgamma(-/-) mice; in contrast, numbers of ICAM-1(+) vessels did not differ between strains. We did not detect endothelial E-selectin, P-selectin, MAdCAM-1, or PNAd in any of the brains. Significantly fewer CD8(+) T cells were recruited into brains of infected IFNgamma(-/-) than WT mice. Treatment of infected IFNgamma(-/-) mice with recombinant IFN-gamma restored the expression of VCAM-1 on their cerebral vessels and recruitment of CD8(+) T cells into their brains, confirming an importance of this cytokine for upregulation of VCAM-1 expression and CD8(+) T cell trafficking. In infected WT and IFNgamma(-/-) animals, almost all cerebral CD8(+) T cells were lymphocyte function-associated antigen-1 (LFA-1)(high), CD44(high), and CD62L(neg), and approximately 38% were alpha4beta1 integrin(+). In adoptive transfer of immune spleen cells, pretreatment of the cells with a monoclonal antibody (mAb) against alpha4 integrin markedly inhibited recruitment of CD8(+) T cells into the brain of chronically infected WT mice. These results indicate that IFN-gamma-induced expression of endothelial VCAM-1 and its binding to alpha4beta1 integrin on CD8(+) T cells is important for recruitment of the T cells into the brain during the chronic stage of T. gondii infection, although LFA-1/ICAM-1 interaction may also be involved in this process.     

Effect of cytokines on the expression of cell adhesion molecule and on the adhesion of melanoma cells to endothelial cells.

We examined the role of cell adhesion molecules (CAM) by which tumor cells bind to the endothelial cells using human umbilical vein endothelial cells (HUVEC) and cultured melanoma cells. Endothelial cells from human umbilical veins were isolated and examined for CAM expression and its modulation by tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6) or interferon-gamma (IFN-gamma). The expression of intercellular adhesion molecule 1 (ICAM-1) on HUVEC was increased by TNF-alpha, IL-1 and IFN-gamma when measured by ELISA or flow cytometric (FACS) analysis. IL-6 did not increase ICAM-1 expression on HUVEC. Two melanoma cell lines, Malme-3M and SK-Mel-28, showed increased expression of ICAM-1 after treatment with TNF-alpha, IL-1 and IFN-gamma in FACS analysis. IFN-gamma induced increased expression of HLA-DR only in SK-Mel-28 melanoma cells, not in Malme-3M melanoma cells. Neither HUVEC nor melanoma cells expressed lymphocyte function-associated antigen 1 (LFA-1) in either the basal (i.e., cytokine untreated) condition or the cytokine treated condition. Melanoma cells showed minimal increment in adhesion to TNF-alpha or IL-1 treated HUVEC than to cytokine untreated HUVEC. HUVEC and melanoma cells did not express LFA-1 and increased ICAM-1 expression by TNF-alpha, IL-1 and IFN-gamma treatment in FACS analysis did not coincide with minimal increase of melanoma cells adhesion to cytokine treated HUVEC. These results suggest that adhesion between melanoma cells and HUVEC is probably mediated by molecular interaction other than ICAM-1/LFA-1.     

Histamine induces IL-6 production by human endothelial cells.

Histamine is one of the major mediators implicated in the physiopathology of allergy. On vascular endothelium, histamine mainly induces early effects: an increase in vasopermeability leading to oedema, a release of lipid mediators and a transient expression of P-selectin. The aim of this study was to evaluate the effects of histamine on adhesion molecule expression and IL-6 production by human endothelial cells. Histamine did not modulate the expression of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, but induced a transient expression of P-selectin as previously reported. In addition, histamine increased in a dose- (from 10(-5) to 10(-3) M) and time- (from 4 h to 24 h) dependent fashion the IL-6 synthesis by endothelial cells. Tumour necrosis factor-alpha (TNF-alpha)-induced IL-6 production was also potentiated in a dose-dependent manner by histamine, without modification of the time course of IL-6 secretion. Moreover, this increase of IL-6 production induced by histamine was inhibited in a dose-dependent manner by H1 and H2 histamine receptor antagonists (50% inhibition of IL-6 production at 5 x 10(-4) M and 4 x 10(-5) M, respectively). So, histamine induces, besides already well known effects, a late stimulation of endothelial cells, i.e. the production of IL-6.     

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.     

Borrelia burgdorferi upregulates expression of adhesion molecules on endothelial cells and promotes transendothelial migration of neutrophils in vitro.

The accumulation of leukocytic infiltrates in perivascular tissues is a key step in the pathogenesis of Lyme disease, a chronic inflammatory disorder caused by Borrelia burgdorferi. During an inflammatory response, endothelial cell adhesion molecules mediate the attachment of circulating leukocytes to the blood vessel wall and their subsequent extravasation into perivascular tissues. Using cultured human umbilical vein endothelial cells (HUVEC) in a whole-cell enzyme-linked immunosorbent assay, we demonstrated that B. burgdorferi activated endothelium in a dose- and time-dependent fashion as measured by upregulation of the adhesion molecules E-selectin, vascular cell adhesion molecule 1 (VCAM-1), and intercellular adhesion molecule 1 (ICAM-1). As few as one spirochete per endothelial cell stimulated increased expression of these molecules. Expression of E-selectin peaked after spirochetes and HUVEC were coincubated for 4 h and returned to near-basal levels by 24 h. In contrast, expression of VCAM-1 and ICAM-1 peaked at 12 h and remained elevated at 24 h. HUVEC monolayers cultured on acellular amniotic tissue were used to investigate the consequences of endothelial cell activation by spirochetes. After incubation of HUVEC-amnion cultures with B. burgdorferi, subsequently added neutrophils migrated across the endothelial monolayers. This process was mediated by E-selectin and by CD11/CD18 leukocytic integrins. The extent of migration depended on both the number of spirochetes used to stimulate the HUVEC and the length of the coincubation period. These results raise the possibility that B. burgdorferi induces a host inflammatory response and accompanying perivascular damage through activation of vascular endothelium.