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Cytomegalovirus- and interferon-related effects on human endothelial cells. Cytomegalovirus infection reduces upregulation of HLA class II antigen expression after treatment with interferon-gamma.

Cultured human umbilical vein endothelial cells (HUVEs) were infected with human cytomegalovirus (HCMV) strain AD169. Up to 50% HUVEs proved to be positive for HCMV early nuclear antigens 24 hours after inoculation with virus. Following infection kinetics of surface expression of HLA class I and II, intercellular adhesion molecule (ICAM-1) and endothelial lymphocyte adhesion molecule (ELAM-1) on HUVEs were investigated by means of flow cytometry. A slight increase in HLA class I expression was observed, whereas expression of HLA class II (DR, DP, DQ) antigens was not induced by infection with HCMV. Furthermore, when compared with uninfected cells treated with interferon-gamma (IFN-gamma), reduced enhancement of HLA-DR expression was conspicuous in HCMV-infected cells treated with IFN-gamma. There is evidence that only a portion of HUVE is affected in its ability to upregulate HLA class II antigens. While expression of ICAM-1 was found to be enhanced between 8 and 20 hours after infection with a maximum at 12 hours after infection, no modulation of ELAM-1 was seen.

Cell Adhesion Molecules↗

The effect of penile tourniquet and continuous artificial erection on penile erectile tissues: An experimental study.

INTRODUCTION: Penile tourniquet (PT) is known to cause ischemic injury, which worsens with prolonged application. Artificial erection (AE), formed by intracorporal saline injection mostly under PT, has been practiced for decades to evaluate penile curvature, yet its effect on erectile tissues has never been investigated. In this study, we examined a modified approach, continuous artificial erection (CAE), and investigated its effects on erectile tissues. OBJECTIVE: This study aims to investigate the histopathological and immunohistochemical effects of CAE on penile erectile tissues. STUDY DESIGN: Thirty-five rats were randomized into five groups. Four experiment groups received 20 or 40 min of isolated PT (20T and 40T) or PT with CAE (20T&E and 40T&E). CAE was achieved through continuous intracavernosal saline injection. Penectomy was performed three weeks post-procedure in the experiment groups and directly in the control group. Erectile tissue samples were evaluated using light microscopy for histopathological parameters including inflammation, neovascularization and fibrosis, and by immunohistochemistry. Endothelial function was assessed by eNOS and e-selectin staining, while ICAM-1 staining was used to assess chronic inflammation. RESULTS: 40T showed the highest levels of inflammation, fibrosis, and endothelial dysfunction. 20T had significantly less inflammation than 40T, with a non-significant increase in fibrosis and alteration of endothelial markers. 40T&E displayed the second-highest fibrosis rate (adjusted p > 0.05), while 20T&E showed complete absence of fibrosis. Both 40T&E and 20T&E preserved strong eNOS and e-selectin expression, identical to controls. ICAM-1 expression in 20T&E was also consistent with the control group. The most significant difference in erectile tissue damage was noted between 40T and 20T&E. CONCLUSION: This is the first study to evaluate the effects of AE on erectile tissues. Findings of this experimental model support that, CAE does not increase the tissue damage that is already caused by PT, but rather reduces it, likely through the washout of blood elements contributing to reperfusion injury. CAE possibly provides a protective effect on erectile tissues by preserving endothelial function, reducing inflammation and fibrosis, especially under 20 minutes of duration. These findings may support that AE maneuvers such as "artificial erection test" and CAE are potentially safe, while further studies are needed to assess the detailed effects of CAE.

Male↗

Vascular cell adhesion molecule-1 (VCAM-1) expression in murine lupus nephritis.

Vascular cell adhesion molecule-1 (VCAM-1) is a cell surface protein which mediates adherence of inflammatory cells to target cells by binding with the beta 1-integrin ligand Very Late Antigen-4 (VLA-4) on leukocytes. The expression of VCAM-1 was investigated in a murine model of lupus nephritis, the autoimmune MRL/lpr mouse. Compared with normal mice, MRL/lpr kidneys show increased VCAM-1 expression not only in the endothelium, but also in cortical tubules and glomeruli. Increased steady-state VCAM-1 mRNA levels (approximately 3 kB) are detected in the kidney of nephritic MRL/lpr mice. Two additional transcripts (approximately 2 and approximately 1.8 kB) are present in autoimmune MRL/lpr but not in normal mice. Like ICAM-1, VCAM-1 is also upregulated in vitro in renal cortical tubular and mesangial cells by TNF-alpha, IL-1 and IFN-gamma. T cell and macrophage cell lines adhere to TNF-alpha stimulated tubular epithelial cells by using the VCAM-1/VLA-4 and the ICAM-1/LFA-1 binding pairs. Kidney tissue sections from nephritic MRL/lpr also display increased adhesiveness for T cell and macrophage cell lines, and for MRL/lpr lymph node cells when compared with normal kidney sections. This enhanced adhesiveness of MRL/lpr kidney tissue is inhibited with monoclonal antibodies targeting the VCAM-1 and ICAM-1 molecules. Thus, VCAM-1 and ICAM-1 function as renal parenchymal adhesion molecules and mediate the adherence of pathogenic inflammatory cells in murine lupus nephritis.

Animals↗

Multiplexed perturbation enables scalable pooled screens.

CRISPR-based genetic perturbation screens have revolutionized the ability to link genes to cellular phenotypes with unprecedented precision and scale; however, conventional pooled CRISPR screens require large cell numbers to achieve adequate sgRNA representation, posing technical and financial challenges. Here, we investigate the impact of co-delivery of multiple guide RNAs via high multiplicity of infection (MOI) in pooled CRISPR interference screens as a strategy to enhance screening efficiency while reducing cell numbers. We systematically evaluate screen performance across varying MOIs, assessing the effects of multiplexing on knockdown efficiency, sgRNA representation and potential interference of multiple sgRNA phenotypes. Our data demonstrate that sgRNA multiplexing (MOI 2.5-10) can maintain screen performance while enabling significant reductions in cell number requirements. We further apply these optimized conditions to conduct a genome-wide CRISPR screen for regulators of the intracellular adhesion molecule ICAM-1, successfully identifying new candidates using as few as half a million cells. This study provides a framework for adopting multiplexed sgRNA strategies to streamline CRISPR screening applications in resource-limited settings.

Humans↗

A mechanism for the antiinflammatory effects of corticosteroids: the glucocorticoid receptor regulates leukocyte adhesion to endothelial cells and expression of endothelial-leukocyte adhesion molecule 1 and intercellular adhesion molecule 1.

Corticosteroids are the preeminent antiinflammatory agents although the molecular mechanisms that impart their efficacy have not been defined. The endothelium plays a critical role in inflammation by directing circulating leukocytes into extravascular tissues by expressing adhesive molecules for leukocytes [e.g., endothelial-leukocyte adhesion molecule 1 (ELAM-1) and intercellular adhesion molecule 1 (ICAM-1)]. We therefore determined whether corticosteroids suppress inflammation by inhibiting endothelial expression of adhesion molecules for neutrophils (polymorphonuclear leukocytes). Preincubation of endothelial cells with endotoxin [lipopolysaccharide (LPS), 1 microgram/ml] led to a 4-fold increase in subsequent adherence of polymorphonuclear leukocytes (P < 0.0001, n = 10) to endothelial cells, an increase that was markedly attenuated when endothelial cells were treated with dexamethasone (IC50 < 1 nM, P < 0.0001, n = 6 or 7) during preincubation with LPS. Moreover, the steroid receptor agonist cortisol (10 microM), but not its inactive metabolite tetrahydrocortisol (10 microM), diminished LPS-induced endothelial cell adhesiveness. Further evidence that the action of dexamethasone was mediated through ligation of corticosteroid receptors [human glucocorticoid receptors (hGRs)] was provided by experiments utilizing the steroid antagonist RU-486. RU-486 (10 microM), which prevents translocation of ligated hGR to the nucleus by inhibiting dissociation of hGR from heat shock protein 90, completely aborted the effect of dexamethasone on adhesiveness of endothelial cells (P < 0.0005, n = 3). Treatment of endothelial cells with LPS (1 microgram/ml) stimulated transcription of ELAM-1, as shown by Northern blot analysis, and expression of membrane-associated ELAM-1 and ICAM-1, as shown by quantitative immunofluorescence (both P < 0.001, n = 9). Dexamethasone markedly inhibited LPS-stimulated accumulation of mRNA for ELAM-1 and expression of ELAM-1 and ICAM-1 (IC50 < 10 nM, both P < 0.001, n = 4-9); inhibition of expression by dexamethasone was reversed by RU-486 (both P < 0.005, n = 4-6). As in the adhesion studies, cortisol but not tetrahydrocortisol inhibited expression of ELAM-1 and ICAM-1 (both P < 0.005, n = 3 or 4). In contrast, sodium salicylate (1 mM) inhibited neither adhesion nor expression of these adhesion molecules. These studies suggest that antagonism by dexamethasone of endotoxin-induced inflammation is a specific instance of the general biological principle that the glucocorticoid receptor is a hormone-dependent regulator of transcription.

Adrenal Cortex Hormones↗

SUMO modification of the Ets-related transcription factor ERM inhibits its transcriptional activity.

A variety of transcription factors are post-translationally modified by SUMO, a 97-residue ubiquitin-like protein bound covalently to the targeted lysine. Here we describe SUMO modification of the Ets family member ERM at positions 89, 263, 293, and 350. To investigate how SUMO modification affects the function of ERM, Ets-responsive intercellular adhesion molecule 1 (ICAM-1) and E74 reporter plasmids were employed to demonstrate that SUMO modification causes inhibition of ERM-dependent transcription without affecting the subcellular localization, stability, or DNA-binding capacity of the protein. When the adenoviral protein Gam1 or the SUMO protease SENP1 was used to inhibit the SUMO modification pathway, ERM-dependent transcription was de-repressed. These results demonstrate that ERM is subject to SUMO modification and that this post-translational modification causes inhibition of transcription-enhancing activity.

Adenoviridae↗

Tumor necrosis factor alpha induces adhesion molecule expression on human fetal astrocytes.

Leukocyte adhesion molecules on endothelial cells of the blood-brain barrier may participate in the entry of leukocytes into the central nervous system. Because astrocytes are also a component of the blood-brain barrier and have been associated with inflammation, we studied the ability of astrocytes to express leukocyte adhesion molecules using Northern blot and immunocytochemical techniques. Astrocytes treated with the proinflammatory cytokine tumor necrosis factor alpha (TNF) expressed messenger RNA for the adhesion molecules E-selectin, vascular cell adhesion molecule 1, and intercellular adhesion molecule 1, as well as their corresponding proteins. In addition, TNF-treated astrocytes expressed a monocyte adhesion protein identified by our laboratory, recognized by the monoclonal antibody IG9. These results indicate that under inflammatory conditions in the central nervous system, such as multiple sclerosis and acquired immune deficiency syndrome, astrocyte expression of adhesion molecules may facilitate the migration of leukocytes and contribute to the disease process.

Astrocytes↗

TCGA-based identification of prognostic biomarkers and candidate traditional Chinese medicine compounds in papillary thyroid carcinoma: An observational study.

This study aimed to identify prognostic genes associated with papillary thyroid carcinoma (PTC) and explore candidate traditional Chinese medicine (TCM) compounds using integrated bioinformatics and molecular docking. In this observational study, PTC gene expression profiles and clinical data were obtained from The Cancer Genome Atlas. Differentially expressed genes were screened using differential-expression sequencing (DESeq2), followed by protein-protein interaction network analysis to identify hub genes. Their expression, diagnostic value, immune relevance, prognostic significance, protein-level validation, and single-cell distribution were assessed using gene expression profiling interactive analysis, receiver operating characteristic analysis, immune infiltration analysis, Kaplan-Meier survival analysis, the human protein atlas, and single-cell RNA-sequencing data. Candidate TCM compounds were predicted using symptom mapping (SymMap) and the TCM Systems Pharmacology Database and Analysis Platform, and molecular docking was performed to evaluate potential ligand-target interactions. Five hub genes, colony-stimulating factor 2, apolipoprotein E, fibronectin 1 (FN1), collagen type I alpha 1 chain (COL1A1), and intercellular adhesion molecule 1, were identified and found to be significantly upregulated in PTC tissues, with diagnostic value in receiver operating characteristic analysis. Immune infiltration analysis showed associations with macrophages, dendritic cells, and T helper 1 cells, whereas single-cell analysis demonstrated heterogeneous expression across immune and stromal cell populations, including fibroblasts. Higher FN1 and COL1A1 expression was associated with poorer outcomes. Immunohistochemistry supported the expression patterns, while single-cell analysis provided exploratory cell-type-level context for the cellular distribution of selected genes. Ginseng and Smilax glabra were predicted as common candidate TCMs, and docking suggested favorable binding between their active compounds and selected hub targets. Colony-stimulating factor 2, apolipoprotein E, FN1, COL1A1, and intercellular adhesion molecule 1 may be biologically relevant hub genes in PTC, while FN1 and COL1A1 may have prognostic value. Predicted TCM compounds provide preliminary computational evidence for possible compound-target interactions, requiring experimental and clinical validation.

Female↗

Adhesion molecules involved in the interaction of LGL/NK cells and human endothelial cells stimulated with Salmonella bacteria.

Previously we showed that pretreatment of LGL/NK or HUVE cells with Salmonella bacteria augments the adhesion of LGL/NK cells to endothelium. Here we analyse the roles of HUVEC adhesion molecules VCAM-1, ICAM-1 and E-selectin, and the counter-receptors VLA-4, LFA-1 and SLex in the increase of LGL/NK adhesion to HUVEC, stimulated with Salmonella Minnesota mR595 bacteria, LPS or TNF-alpha. On Salmonella-stimulated HUVEC, VCAM-1 and ICAM-1 were the major binding structures involved, and their effect was additive in monoclonal antibody inhibition experiments. We could demonstrate the induction of both structures on cultured HUVEC after 24 h of Salmonella stimulation in flow cytometric analysis. For Salmonella-stimulated LGL/NK, the principal binding structure was LFA-1. Stimulation of LGL/NK cells did not alter the expression of the adhesion structures (subunits CD11a/CD18, CD49d/CD29), as determined by flow cytometric analysis, and thus the increased adherence is presumably produced by an increased avidity of the receptors on LGL/NK cells. Pretreatment of endothelium or lymphocytes with various stimuli, including Salmonella bacteria or LPS, leads to an activation state which provides for characteristic anchorage sites for the increased migration of LGL/NK cells towards the site of inflammation.

Antibodies, Monoclonal↗

Human blood dendritic cells exhibit a distinct T-cell-stimulating mechanism and differentiation pattern.

In this study, the mechanisms underlying stimulation of T-cell proliferation by human blood dendritic cells (BDC) and their differentiation have been defined with a panel of monoclonal antibodies (MoAbs). It was found that the MoAbs against LFA-1 (CD11a), CD11c, LFA-3 (CD58), ICAM-1 (CD54) or HLA-DR could significantly suppress T-cell proliferation in an allogeneic mixed lymphocyte reaction (P < 0.05), while being unable to inhibit clustering of BDC with T cells. Addition of anti-CD18 or CD45 MoAbs increased the size of clusters after 18 h of culture, but had no effect on the proliferation of T cells (P < 0.05). The suppressive effect of the MoAbs may be viewed not as an inhibition of contact between BDC and T cells, but rather as a blocking of co-stimulatory signals for T-cell activation, which are mediated by interaction of the adhesion molecules. After depleting the BDC preparations of monocytes, we used a double staining in FACS analysis to demonstrate that BDC do not express specific T (CD3), B (CD20 and CD21) and myeloid cell markers (CD11b, CD13 and CD14), but abundant class II antigens. This pattern remained unaltered after 8 days of culture in the presence of 100 U/ml GM-CSF, although a threefold increase of HLA-DQ and ICAM-1 molecules on the cultured cells was observed.

Antibodies, Monoclonal↗

Expression of vascular cell adhesion molecule-1 in human renal allografts.

The expression of vascular cell adhesion molecule-1 (VCAM-1) in 11 human renal allograft biopsies and 3 normal kidney specimens was investigated by immunocytochemistry. VCAM-1 expression was correlated with the degree of CD3+ T cell infiltration and the clinicopathologic diagnosis of acute rejection. CD3+ infiltrates were seen in all biopsies with rejection, but not in normal biopsies or one with acute tubular necrosis, and were accompanied by CD68+ monocyte/macrophage infiltrates. In normal biopsies, VCAM-1 was present on occasional tubules, where its expression was patchy and restricted to the basolateral surface of cells with slight cytoplasmic staining. The total number of tubules expressing VCAM-1 significantly increased in specimens infiltrated with CD3+ T cells. Moreover, in these infiltrated biopsy specimens, VCAM-1 was present throughout the cytoplasm of tubular cells concentrated on the basolateral surface. VCAM-1 was also observed on vascular endothelial cells where its expression correlated with the degree of CD3+ infiltrate. Mean scores (0 to 3+) for endothelial VCAM-1 expression increased from 0 (CD3+ score, 0) to a mean score of 2.25 in association with CD3+ T cell infiltrates (CD3+ score, 3). Endothelial VCAM-1 was predominantly on vessels in areas of infiltrate, including peritubular capillaries, venules, and arterioles, but was notably absent on glomerular endothelium. VCAM-1 also stained mesangial cells in an occasional CD3+ infiltrated specimen. It was concluded that the expression of VCAM-1 is increased on renal tubules and renovascular endothelium in rejecting renal allografts in association with CD3+ infiltrates.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

Multi-omics-based study on the biological characteristics of kidney renal deficiency and blood stasis in ankylosing spondylitis.

OBJECIVE: To explore the objective biological evidence for the classification and diagnosis of Traditional Chinese Medicine (TCM) syndromes in ankylosing spondylitis (AS) using multiomics analysis. METHODS: Patients with AS were categorized into kidney deficiency and blood stasis syndrome (SX group) and damp-heat stasis syndrome (SR group). Transcriptomic sequencing and quantitative plasma proteomics were performed on patients with AS and healthy volunteers. Multiomics integration was used to characterize the biological basis of AS with renal deficiency and blood stasis syndrome. Specific proteins were validated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). RESULTS: Transcriptomic sequencing identified 31 significantly upregulated genes in patients with AS compared to healthy controls. These genes were primarily involved in tumor necrosis factor, interleukin-17, and nuclear factor kappa-B signaling pathways, as well as osteoblast differentiation and various viral infection pathways. Differentially expressed genes, including intercellular adhesion molecule 1 (ICAM1), 6-phosphofructo-2-kinase, cyclin-dependent kinase inhibitor 1A, interleukin 1 receptor antagonist, integrin alpha IIb, and myosin light chain 9 were more upregulated in the SX group than in the SR group. Quantitative proteomics identified 723 differential proteins associated with the disease and 788 differential proteins between the SX and SR groups. Notable proteins such as myeloperoxidase, cluster of differentiation 14, macrophage simulating 1 (MST1), and Ras homolog enriched in brain may serve as characteristic proteins of the SX group. By integrating transcriptomic and proteomic data, 45 associated differential molecules involved in platelet activation, pathogenic intestinal flora infection, glycolysis/gluconeogenesis, and T-cell receptor signaling pathways were identified in patients with AS compared to healthy controls. Additionally, ICAM1, MST1, C-X-C motif chemokine ligand 8 (CXCL8), suppressor of cytokine signaling 3 (SOCS3), and insulin-like growth factor binding protein 1 (IGFBP1) were detected in TCM syndromes by RT-qPCR and ELISA, showing upregulation in AS renal deficiency and blood stasis syndromes, which is consistent with the proteomic and transcriptomic results. CONCLUSIONS: ICAM1, MST1, CXCL8, SOCS3, and IGFBP1 were identified as biomarkers of renal deficiency and blood stasis syndrome in AS. This study provides a biological basis for the differential diagnosis of TCM syndromes in AS, offering new insights into Chinese medicine evidence and more precise Chinese medicine treatments for AS.

Humans↗

Elevated levels of circulating adhesion molecules in IDDM patients and in subjects at risk for IDDM.

Serum levels of recently discovered circulating forms of adhesion molecules, ICAM-1 and L-selectin, were found to be elevated in IDDM patients and in subjects at risk for developing IDDM compared with 100 normal, nondiabetic blood donors. Both adhesion molecules were determined by sandwich ELISA. Serum concentrations of either clCAM-1 or cL-selectin were > 2SD of normal mean in 10 of 14 recent-onset IDDM patients (P < 0.05). Serum levels of clCAM-1 and cL-selectin did not correlate. In first-degree relatives, elevated adhesion molecule levels were observed in the 6 ICA+ individuals and in the ICA- individuals all (n = 14) with a genetic risk of IDDM (sharing HLA-DR3 and/or-DR4 with the diabetic relative) but not in the HLA-DR3- and/or -DR4- relatives (n = 13). We conclude that elevated clCAM-1 and cL-selectin levels occur independently of ICA status and probably reflect ongoing immune processes in recent-onset IDDM patients and first-degree relatives at risk for IDDM.

Adult↗

Molecular interactions mediating T-B lymphocyte collaboration in human lymphoid follicles. Roles of T cell-B-cell-activating molecule (5c8 antigen) and CD40 in contact-dependent help.

In lymphoid follicles, CD4+ T lymphocytes provide contact-dependent stimuli to B cells that are critical for the generation of specific antibody responses in a process termed Th function. The CD4+ T cell-restricted surface activation protein, 5c8 Ag (T-BAM), has recently been shown to be a component of the contact-dependent helper signal to B cells. To further dissect this process, we utilized a Jurkat T cell lymphoma clone, termed D1.1, that constitutively expresses T-BAM and activates peripheral B cells to express surface CD23 in a contact-dependent mechanism that is inhibited by mAb anti-T-BAM (5c8). Similar to its effect on peripheral B cells, Jurkat D1.1 activates B cells from lymphoid organs, as well as a B cell lymphoma clone, RAMOS 266,4CN 3F10 (RAMOS 266), to up-regulate surface CD23. Interestingly, mAb to the B cell surface molecule, CD40 (mAb G28-5 and B-B20), inhibit D1.1 induced activation of RAMOS 266 and peripheral and lymphoid B cells. In contrast, mAb to CR2 or the adhesion molecules, LFA1, LFA3, or ICAM-1, have little effect. The inhibitory effect of anti-CD40 mAb on B cell activation induced by D1.1 is specific because anti-CD40 potentiates, rather than inhibits, the up-regulation of CD23 on B cells induced by rIL-4. Moreover, cross-linking CD40 molecules by anti-CD40 mAb bound to Fc gamma RII+ (CD32) L cells induces B cell CD23 expression. In vivo, T-BAM-expressing cells are CD4+ T cells that are restricted to lymphoid organs and are localized in the mantle and centrocytic zones of lymphoid follicles and the spleen periarteriolar lymphoid sheath in association with CD40+ B cells. Taken together, these data demonstrate that T-BAM on T cells and CD40 on B cells are involved in contact-dependent T-B help interactions that occur in lymphoid follicles.

Antigens, CD↗

Adhesion molecules on the endothelium and mononuclear cells in human atherosclerotic lesions.

Atherosclerotic lesions show features of a cell-mediated immune inflammatory process. From this viewpoint, the potential role of arterial endothelium in the recruitment of mononuclear cells (T lymphocytes and macrophages) was studied. The endothelium of diffuse intimal thickening (DIT) and atheromatous plaques (AP) in human coronary arteries and abdominal aortas was characterized for the expression of adhesion molecules ELAM-1, ICAM-1, and the major histocompatibility complex (MHC) class II antigens HLA-DR/DP. A marked increase in expression of ICAM-1 and ELAM-1, and to a lesser extent HLA-DR/DP was observed on endothelial cells that were adjacent to subendothelial infiltrates of T lymphocytes (CD3+, CD11a+, HLA-DR/DP+) and macrophages (CD14+, CD11a+, CD11c+, HLA-DR/DP+). This contrasted with a lower or absent expression of these activation markers at sites without prominent inflammatory cell infiltrates. These findings could be demonstrated in DIT as well as in AP. The observations suggest that cytokines produced by the subintimal infiltrates may activate the endothelium in a similar way as is observed in the microvasculature at sites of immune inflammation. The expression of these activation markers in the microvasculature is associated with enhanced leukocyte adhesion, permeability for macromolecules, and procoagulant activity, features known to occur also in early experimental atherosclerosis. The findings therefore support the concept that arterial endothelium plays an active role in the recruitment of mononuclear cells in atherosclerotic lesions.

Adult↗

Contribution of ICAM-1 and VCAM-1 to the morphological changes in monocytes bound to human venous endothelial cells stimulated with recombinant interleukin-4 (rIL-4) or rIL-1 alpha.

The present study focused on the question of whether the expression of intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) on the surface of cultured human venous endothelial cells (EC), stimulated with recombinant interleukin-4 (rIL-4) or rIL-1 alpha, contributes to the stretching of human monocytes following their binding to EC. Stimulation of monolayers of venous EC with rIL-4 for 24 hr induced marked expression of VCAM-1 but not ICAM-1 on EC, increased the adhesiveness of EC for monocytes but did not promote stretching of EC-bound monocytes over the surface of EC. Stimulation of EC with rIL-1 alpha for 24 hr induced surface expression of both ICAM-1 and VCAM-1, enhanced the binding of monocytes to EC and increased the percentage of EC-bound monocytes with a stretched morphology about 2.7-fold. Anti-ICAM-1 but not anti-VCAM-1 mAb markedly reduced the percentage stretched monocytes on rIL-1 alpha-stimulated EC. We conclude that ICAM-1 but not VCAM-1 on cytokine-stimulated EC is essential for the stretching of EC-bound monocytes.

Cell Adhesion↗

[The onset mechanism of experimental autoimmune uveoretinitis induced by interphotoreceptor retinoid-binding protein].

In order to analyze the onset mechanism of experimental autoimmune uveoretinitis (EAU), two experimental models were used; one was EAU induced by one injection of purified bovine interphotoreceptor retinoid-binding protein (IRBP) with complete Freund's adjuvant in Lewis rat, and the other was an IRBP-induced autoimmune uveoretinitis that occurred spontaneously in nude (nu/nu) mice at 4 weeks of age reconstituted by the grafting of rat embryonic thymus (TG nude mouse). EAU develops when the IRBP-reactive lymphocytes in the regional lymph-nodes are activated. Activation begins when the T lymphocyte recognizes the peptide for the epitope bound to a major histocompatibility complex (MHC) molecule in the antigen-presenting cell by way of the T-cell receptor (TCR). In EAU, ten peptide residues p1182-1191 of the IRBP amino acid sequence, were revealed to be sufficiently capable of lymphocyte activation for EAU, and it was also shown that amino acid positions 1182W (tryptophane), 1185G (glycine), 1186V (valine) and 1188P (proline) of IRBP play important roles as the epitopes or agretopes in developing EAU. On the other hand, two amino acids of IRBP, amino acid positions 1182W (tryptophane) and 1194P (proline) were shown to be the agretopes inducing autoimmune uveoretinitis in the TG nude mouse. A study of the variable region of the TCR with a residual p1182-1194 specific T-cell line from the TG nude mouse revealed that as many as 96% utilized the T-cell receptor V beta 6 gene and that the peptide-MHC molecule complex was recognized by restricted receptors. Adhesion molecules such as ICAM-1 and LFA-1 were also found to play an important role as cofactors in activation of lymphocytes in the antigen-recognition process of EAU. Uveoretinitis seemed to result from an immune reaction in the eye occurring when the T lymphocyte arrives there, activating the immunological process. ICAM-1 and LFA-1 were also found to be involved in the infiltration process of inflammatory cells: our immunohistological examination revealed that ICAM-1 was present in the retinal pigment epithelium and epithelium of the ciliary body composing the blood-ocular barrier. In contrast, LFA-1 was expressed in the infiltrating cells. Finally, the tolerance of IRBP was discussed and it was experimentally demonstrated that the absence of IRBP-induced uveoretinitis in human beings and certain experimental animals resulted from endogenous IRBP serving as a tolerogen; we assumed that the breakdown of this self-tolerance would induce EAU due to thymic dysfunction or IRBP antigen injection.

Amino Acid Sequence↗