T lymphocyte adhesion to human synovial fibroblasts. Role of cytokines and the interaction between intercellular adhesion molecule 1 and CD11a/CD18.

We studied the adhesion of human peripheral blood T lymphocytes to human synovial fibroblasts stimulated with interferon-gamma (IFN gamma), tumor necrosis factor alpha (TNF alpha), interleukin-1 beta (IL-1 beta), or combinations of these cytokines. T lymphocytes bound poorly to untreated human synovial fibroblasts. IFN gamma treatment resulted in the largest increase in adhesion, followed by TNF alpha and IL-1 beta. Combinations of IFN gamma + TNF alpha and IFN gamma + IL-1 beta had a synergistic effect on intercellular adhesion molecule 1 (ICAM-1) expression and adhesion. The increase in cellular adhesion induced by cytokines correlated with the up-regulation of the number of cells expressing ICAM-1 and the density of antigen/cell. There was no synergistic effect on leukocyte function-associated antigen 3 (LFA-3) or on HLA class I or class II antigen expression. Adhesion was only partially inhibited by anti-ICAM-1, anti-LFA-1, or anti-CD18. These findings suggest the existence of ICAM-1--independent and CD11/CD18-independent adhesion mechanisms. Anti-LFA-3 was completely ineffective as an inhibitor of adhesion. There was no additive or synergistic advantage of using combinations of antibodies to increase the level of inhibition, i.e., anti--ICAM-1 + anti-LFA-3, anti-ICAM-1 + anti-CD18, or anti-ICAM-1 + anti-LFA-1 (CD11a). Our data indicate that proinflammatory cytokines may play a prominent role in the formation and exacerbation of synovial hyperplasia, by regulating the recruitment and retention of T lymphocytes via the up-regulation of adhesion molecules on synovial fibroblasts.     

Immunohistologic analysis of the distribution of cell adhesion molecules within the inflammatory synovial microenvironment

Antigen-independent binding of T lymphocytes to a variety of cell types has been shown to be mediated by receptor-ligand pairs of adhesion molecules. In forms of inflammatory synovitis (including rheumatoid arthritis), T cells home to synovium, become activated, and participate in the generation of chronic synovitis. Using indirect immunofluorescence assays on synovial frozen tissue sections and on synovial fibroblast cell lines, we studied the distribution of cell adhesion molecules on components of the synovial microenvironment in inflammatory synovitis. We reasoned that analysis of the cell types within synovium that express adhesion molecules might provide clues to lymphocyte-stromal interactions that occur in inflammatory synovitis. We found that antibodies against the lymphocyte function-associated antigen 3 (LFA-3) molecule and the intercellular adhesion molecule 1 (ICAM-1) both reacted with macrophage-like type A synovial cells and synovial fibroblasts, as well as with tissue macrophages and vessel endothelium. Using flow cytometry, we found that anti-LFA-3 and anti-ICAM-1 (but not antibodies against their ligands CD2 and LFA-1) reacted with synovial fibroblast cells cultured in vitro. Thus, these data demonstrate that the ligands for lymphocyte LFA-1 molecules (ICAM-1) and for T cell CD2 molecules (LFA-3) are widely distributed among cell types of the synovial microenvironment and provide numerous cell types with which lymphocytes can interact via these 2 adhesion pathways during the course of inflammatory synovitis.     

Selective in vivo growth of lymphocyte function- associated antigen-1-positive murine myeloma cells. Involvement of function-associated antigen-1-mediated homotypic cell-cell adhesion

OBJECTIVES: Lymphocyte function-associated antigen-1 (LFA-1) expression on multiple myeloma cells and its potential role in myeloma biology have been the subject of conflicting literature reports. In this study we used the 5T experimental mouse model to analyze the involvement of LFA-1 in myeloma cell bone marrow homing, survival, and growth. MATERIALS AND METHODS: The 5T33MM vitro (5T33MMvt) myeloma line was used. LFA-1 and intercellular adhesion molecule-1 (ICAM-1) expression were analyzed by flow cytometry. A small molecule antagonist of LFA-1/ICAM interactions, BIRT 377, was used to block LFA-1 in vitro. Transendothelial migration was assessed by measuring migration through Transwells coated with bone marrow endothelial cells. Immediate in vivo homing was analyzed by tracing 51Cr-labeled cells. Invert microscopic cell counting was used to analyze homotypic cell adhesion. Cell cycle analysis was used to analyze apoptosis. S+G(2)/M phase analysis and 3H-thymidine incorporation were used to assess proliferation. Cells were separated into LFA-1(+) and LFA-1(-) fraction by magnetic activated cell sorting. RESULTS: 5T33MMvt cells had a heterogeneous LFA-1 expression and all cells were positive for the LFA-1 ligand ICAM-1. LFA-1 inhibition with BIRT 377 did not affect transendothelial migration of the 5T33MMvt cells; however, it did result in cell cluster scattering, indicating LFA-1 involvement in homotypic cell-cell adhesion. No effect was observed on apoptosis, but the percentage of cells in S+G(2)/M phase was decreased by 39%. 3H-thymidine incorporation confirmed this effect on 5T33MMvt cell proliferation (38% reduction). When 5T33MMvt cells were injected into animals, all myeloma cells isolated at the end stage of the disease were LFA-1(+) in contrast to the situation before injection. LFA-1(+) and LFA-1(-) MM cells had similar in vivo bone marrow homing capacities. Mice injected with LFA-1(+) 5T33MMvt cells developed myeloma (5/5) within 12 weeks after injection. In contrast, LFA-1(-) recipients did not develop the disease (0/5), even 1 year after tumor inoculation. CONCLUSIONS: Our data suggest that LFA-1-mediated homotypic cell-cell adhesion is involved in myeloma cell proliferation and raises the possibility that this interaction may have a crucial role in in vivo myeloma cell growth. LFA-1 does not appear to play a role in the bone marrow homing of these cells.     

Re-evaluation of the involvement of the adhesion molecules ICAM-1/LFA-1 in syncytia formation of HIV-1-infected subclones of a CEM T-cell leukemic line.

The role of the adhesion molecules intercellular adhesion molecule-1 (ICAM-1) and LFA-1 in human immunodeficiency virus type 1 (HIV-1)-induced cell fusion was investigated in subclones of a T-cell leukemic cell line (CEM) with differing abilities to form syncytia. Addition of monoclonal antibodies 84H10 directed against ICAM-1 and MHM23 directed against the common beta subunit of LFA-1 (CD18) resulted in greater than 50% suppression of syncytia formation in cultures of these clones infected with cell-free virus. Two subclones, 2G5-144-84 and 2G5-1, were deficient in their ability to form syncytia and expressed reduced amounts of LFA-1 compared with the parental line. The expression of ICAM-1 but not LFA-1 was upregulated on the clones following treatment with interferon-gamma (IFN gamma); however, this did not overcome the delay in syncytia formation observed in these cells. The syncytia-positive subclones 1B11-39 and 17D-9 expressed high levels of LFA-1. Basal expression of ICAM-1 was upregulated on these cells by treatment with tumor necrosis factor-alpha (TNF alpha), which also accelerated and enhanced syncytia formation. However, anti-ICAM-1 and anti-LFA-1 (CD18) antibodies did not reverse the TNF alpha-induced enhancement of syncytia formation of HIV-1-infected clones 1B11-39 and 17D-9. Under conditions of low viral expression, adhesion molecules may contribute to syncytia formation if adequate levels of both receptor and ligand in the ICAM-1/LFA-1 complex are expressed.(ABSTRACT TRUNCATED AT 250 WORDS)     

细胞黏附分子-1在急性髓性白血病细胞与内皮细胞黏附中的作用

目的　检测急性髓性白血病 (AML)细胞与内皮细胞的黏附及细胞黏附分子 1(ICAM 1)及其配体淋巴细胞功能相关抗原 1(LFA 1)在黏附中的作用。方法　观察AML细胞与静止内皮细胞和肿瘤坏死因子α(TNFα)激活的内皮细胞的黏附 ;AML细胞与内皮细胞混合培养 2 4h的黏附 ;正常中性粒细胞与AML细胞培养上清作用 2 4h后的内皮细胞的黏附 ;流式和ELISA方法检测AML细胞培养上清作用后内皮细胞ICAM 1及可溶性ICAM 1的表达 ;并用ICAM 1和LFA 1的抗体进行阻滞黏附试验。结果　AML细胞与静止的内皮细胞黏附较少 (2 4 33± 2 87) % ,AML细胞与TNFα激活的内皮细胞的黏附 ,与内皮细胞混合培养 2 4h后的黏附以及正常中性粒细胞与AML细胞培养上清作用后内皮细胞的黏附明显增加 ,分别为 (81 87± 4 0 8) % ,(82 0 6± 7 0 5 ) % ,(83 99± 3 86 ) % (n =2 1,P <0 0 0 1) ;静止的内皮细胞ICAM 1及可溶性ICAM 1的表达分别为 (5 5 81± 4 11) %和 (0 839± 0 2 36 )μg/L ;AML细胞培养上清作用后内皮细胞ICAM 1及可溶性ICAM 1的表达明显增加 ,分别为 (6 5 36±5 97) %和 (1 4 2 4± 0 4 6 9) μg/L(n =2 1,P <0 0 5 ) ;用ICAM 1及LFA 1的抗体进行黏附阻滞后 ,AML细胞与TNFα激活的内皮细胞的黏附下降为 (2 0 12±     

Role of intercellular adhesion molecule-1 and lymphocyte function-associated antigen-1 during nonsuppurative destructive cholangitis in a mouse graft-versus-host disease model

Intercellular adhesion molecule-1 (ICAM-1) is expressed abnormally on the bile duct epithelium during the course of primary biliary cirrhosis (PBC), but the importance of ICAM-1 and its lymphocyte function-associated antigen-1 (LFA-1) receptor during the course of nonsuppurative destructive cholangitis (NSDC) has not been defined. To address this question, we defined the relationship between ICAM-1 on the intrahepatic bile duct epithelium and the evolution of NSDC lesions in a mouse graft-versus-host disease (GVHD) model. We also determined the effects of anti-ICAM-1 and anti-LFA-1 treatments on NSDC, intrahepatic lymphokine production, and the homing of lymphocytes to the livers of GVHD mice. ICAM-1 was initially detected on the bile duct epithelium and portal vein endothelium on day 7 of GVHD. There was a significant positive correlation between the intensity of ICAM-1 staining and histological bile duct damage (r =.58, P <.05) between day 3 and 28. Treatment with anti-ICAM-1 (but not anti-LFA-1) decreased both the mean grades of portal inflammation (P =.003) and NSDC (P =.002) lesions compared with control immunoglobulin G (IgG) treatments. Combined treatment with anti-ICAM-1 and anti-LFA-1 caused a further decrease in the amount of portal inflammation and bile duct damage compared with anti-ICAM-1, alone (P =.02). Anti-ICAM-1 treatment also decreased both the percentage of T cells and the production of interleukin-2 (IL-2) and IL-12 in the liver (P <.01), but had no effect on IL-4, IL-10, and interferon gamma. Neither anti-ICAM-1 nor anti-LFA-1 prevented lymphocytes from homing to the liver. These results indicate that both ICAM-1 and LFA-1 are important to the pathogenesis of NSDC.     

Increased expression of leukocyte function associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) by alveolar macrophages of patients with pulmonary sarcoidosis.

Leukocyte function associated antigen-1 (LFA-1) and its ligand intercellular adhesion molecule-1 (ICAM-1) are cell adhesion molecules that play an important role in the capacity of monoculear phagocytes (MPs) to present antigens to T lymphocytes. Since in pulmonary sarcoidosis (PS) this capacity is increased at sites of disease activity, we studied the expression of LFA-1 and ICAM-1 on peripheral blood monocytes (BMs) and alveolar macrophages (AM) obtained by bronchoalveolar lavage (BAL) from normal subjects (n = 7) and patients with PS (n = 14). To accomplish this, immunocytochemical stainings were made on cytocentrifuge preparations using anti-LFA-1 (anti-CD 11a) and anti-ICAM-1 (anti-CD 54) monoclonal antibodies (MoAbs). Normal and sarcoid BMs displayed a high percentage of positivity with both MoAbs with no difference between study groups (LFA-1: control BM 87.8 +/- 8.8 percent; sarcoid BM 84.7 +/- 9.5 percent; ICAM-1: control BM 80.8 +/- 10 percent; sarcoid BM 88.0 +/- 4.2 percent; p = NS for all comparisons). In both groups the percentage of cells expressing LFA-1 and ICAM-1 molecules among AMs was lower than among autologous BMs (LFA-1: control AM 46.5 +/- 13.2 percent, p less than 0.001 vs control BM; sarcoid AM 64.2 +/- 15.9; p less than 0.001 vs sarcoid BM) (ICAM-1: control AM 42.7 +/- 8.5 percent, p less than 0.001 vs control BM; sarcoid AM 72.1 +/- 10.6, p less than 0.001 vs sarcoid BM). AMs from patients with PS showed a higher degree of positivity for LFA-1 and ICAM-1 than normal AMs (p less than 0.02 and p less than 0.001, respectively). The positivity for LFA-1 and ICAM-1 molecules on sarcoid AMs was not correlated with the positivity for two different BM-associated markers (ie, the CD 11b and the CD 14 molecules) and was not correlated with the percentage of T lymphocytes in BAL, selected as a marker of the intensity of the alveolitis. These results suggest that the increased ability of sarcoid AMs to induce the proliferation of T lymphocytes may be related, at least in part, to the increased expression of LFA-1 and ICAM-1 molecules on their surfaces.     

Low expression of lymphocyte function-associated antigen (LFA)-1 and LFA-3 adhesion molecules is a common trait in Burkitt's lymphoma associated with and not associated with Epstein-Barr virus.

Lymphocyte function-associated antigens 1 and 3 (LFA-1, LFA-3) and intercellular adhesion molecule 1 (ICAM-1) are cell surface adhesion molecules necessary for immune processes requiring intercellular contact. It was recently proposed that malignant Burkitt's lymphoma cells (BL) may escape from immunosurveillance through the downregulation of LFA-1 (CD11a/CD18) or LFA-3 (CD58) and ICAM-1 (CD54) molecules. Expression of these three adhesion antigens was investigated in 19 BL lines. LFA-1 or LFA-3 expression was found to be absent or low in 8 of 11 Epstein-Barr virus (EBV) genome positive BL, but strongly expressed on all nonmalignant EBV genome positive lymphoblastoid cell lines (LCL). Negative or weak expression of LFA-1 and LFA-3 was also observed in 7 of 8 EBV genome negative BL. ICAM-1 was found to be expressed on the cell surface of the majority of BL lines. BL lines growing as individual cells did not express LFA-1, whereas clump-forming BL lines expressed this marker involved in B-cell homotypic aggregation. Expression of LFA-1 and LFA-3 was induced on in vitro infection of EBV-negative BL cells with the immortalizing EBV strain B95-8, and weakly with the nonimmortalizing EBV strain P3HR1. EBNA2 and LMP, two EBV encoded proteins expressed in LCL and in BL infected with B95-8 (BL/B95-8), are not expressed in P3HR1 infected BL cells (BL/P3HR1). Stable expression of EBNA2 after gene transfer in a BL/P3HR1 cell line did not restore the level of LFA-1 and LFA-3 found on BL/B95-8 cells. In EBV-positive BL cells expressing LFA-1 and LFA-3, LMP was found coexpressed, supporting the recent finding of the role of LMP in B-cell adhesion receptor activation. Consequently, diminished LFA-1 and LFA-3 expression appears to be a common characteristic of numerous EBV-positive BL as well as EBV-negative BL. These findings are discussed in the framework of BL pathogenesis.     

Overexpression of the homeobox gene DLX-7 inhibits apoptosis by induced expression of intercellular adhesion molecule-1

OBJECTIVE: DLX genes constitute a subfamily of divergent homeobox genes. We have previously reported that inhibition of DLX-7 expression by an antisense oligonucleotide caused apoptosis in the K562 erythroleukemia cell line, which highly expresses DLX-7. In this study, we have constructed an expression vector encoding human DLX-7, and examined the effects of overexpression of DLX-7 in the IL-3-dependent lymphoid precursor cell line Ba/F3. METHODS: DLX-7 expression vector was electroporated into Ba/F3 cells, and generate a DLX-7 expressing Ba/F3 cells. Northern blot analysis was performed to determine DLX-7 gene expression. WST-1 assay was used to cell proliferation assay. To detect apoptosis, we performed TUNEL assay. Expression of cell surface adhesion molecules was examined by FACS analysis. RESULTS: Growth properties of DLX-7-transfected Ba/F3 cells in the presence of IL-3, did not differ from those of control Ba/F3 cells. However, in the absence of IL-3, DLX-7-transfected cells abrogated growth dependence on cytokines due to inhibition of apoptosis. Because adhesion properties of DLX-7-transfected cells increase, we examined expression of adhesion molecules in these cells. Expression of intercellular adhesion molecule (ICAM)-1 and ICAM-2 were markedly upregulated in DLX-7-transfected cells. Both anti-ICAM-1 antibody and anti-LFA-1 antibody blocked the aggregation of DLX-7-transfected cells. Moreover, in the absence of IL-3, cytokine-independent cell growth was blocked by anti-ICAM-1 antibody. CONCLUSION: These results indicate that DLX-7 overexpression blocks apoptosis and that ICAM-1 expression induced by DLX-7 contributes to this antiapoptotic effect.     

Expression of adhesion molecules LFA-3 and N-CAM on normal and malignant human plasma cells

Normal and malignant plasma cells were investigated for the expression of seven cellular adhesion molecules by immunofluorescence microscopy. The antigens investigated were CD2 and its ligand, LFA-3 (CD58). LFA-1 alpha (CD11a) and LFA-1 beta (CD18) and their ligand ICAM-1 (CD54), H-CAM (lymphocyte homing receptor; CD44) and N-CAM (CD56). Marrow from 18 patients with myeloma, two with plasma cell leukaemia (PCL), four with monoclonal gammopathy of uncertain significance (MGUS) and 10 normal allogeneic bone marrow donors was studied. All plasma cells from normals and multiple myeloma patients were negative for CD2, CD11a and CD18. All normal and myeloma marrow plasma cells were positive for ICAM-1. 16/18 myeloma cases tested, and all other samples (normal, MGUS and PCL), contained plasma cells positive for H-CAM. Only one normal, but 12/16 myelomas tested were positive for N-CAM (P less than 0.02). One of four MGUS cases was moderately positive and one other weakly positive for N-CAM. Both PCLs were N-CAM negative. 12/18 myelomas were positive for LFA-3, but only two normals (P less than 0.05). All MGUS cases were negative for LFA-3, as was one PCL, the other being weakly positive. Three cases were negative for both adhesion molecules, three cases expressed only N-CAM or LFA-3 and 10 cases expressed both. LFA-3 and N-CAM are expressed significantly in myeloma rather than normal plasma cells. Cases of MGUS may express N-CAM but not, in this small series, LFA-3. Plasma cells in the peripheral blood (PCL) and plasma cell lines express little or no LFA-3 or N-CAM.     

Lymphocyte homing in xenotransplanted human thyroid tissue can be inhibited by LFA-1 and ICAM-1 antibodies.

OBJECTIVES: Homing of lymphocytes is an important factor with respect to the initiation of the autoimmune process in Graves' disease (GD). As previously shown, human lymphocytes, particularly of intrathyroidal origin, derived from patients with GD, are able to migrate into normal xenotransplanted thyroid tissue and induce functional and histological changes. The aim of this study was to investigate the effect of LFA-1 and ICAM-1 antibodies on the homing of lymphocytes of different origin into xenografted human thyroid tissue. METHODS: Eighty-five nude mice bearing 8-week-old xenografts of normal human thyroid tissue were treated twice with anti-CD 54 (anti-ICAM-1), anti-CD 11a (anti-LFA-1), a combination of both, or, serving as controls, iso-antibodies without specific binding capacity or saline. Thereafter, intrathyroidal (ITL) or peripheral blood lymphocytes (PBL) obtained from 4 patients with GD or saline were injected into the animals (i.v., 0.2 mL, 10(6) cells). After 48 hours the mice were sacrificed and transplants as well as mice thyroids were examined by immunohistochemical staining with Ki67, CD3, HLA-II (DAKO, Hamburg), IgG, CD44, ICAM-1, and VCAM-1 (Immunotech, Hamburg). RESULTS: Pretreatment with anti-ICAM-1 and anti-LFA-1 decreased lymphocyte homing (CD3-staining), and expression of HLA-II, IgG, CD44, and VCAM-1 in the transplants. CONCLUSION: Our data show that [ICAM-1/LFA-1 stimulated (induced)] lymphocyte homing and subsequently thyrocyte proliferation are inhibited by ICAM-1 and LFA-1 antibodies in xenotransplanted thyroid tissue. This suggests that ICAM1 and LFA-1 play an important role in the early steps of autoimmune thyroid disease. The inhibition/suppression of ICAM-1 and LFA-1 interaction by respective antibodies, as demonstrated in the present study, may provide a new concept for prophylaxis and therapy.     

Enhancement of G-CSF-induced stem cell mobilization by antibodies against the beta 2 integrins LFA-1 and Mac-1

The beta 2 integrins leukocyte function antigen-1 (LFA-1, CD11a) and macrophage antigen-1 (Mac-1, CD11b) have been reported to play a role in the attachment of CD34(+) cells to stromal cells in the bone marrow. When administered prior to interleukin-8 (IL-8), anti-LFA-1 antibodies completely prevent the IL-8-induced mobilization of hematopoietic stem cells in mice. Here, we studied the role of anti-beta 2 integrin antibodies in granulocyte colony-stimulating factor (G-CSF)-induced mobilization of hematopoietic progenitor cells. Administration of antibodies against the alpha chain of LFA-1 or against the alpha chain of Mac-1 followed by daily injections of G-CSF for more than 1 day resulted in a significant enhancement of mobilization of hematopoietic progenitor cells when compared with mobilization induced by G-CSF alone. Also, the number of late (day 28) cobblestone area-forming cells in vitro was significantly higher after mobilization with anti-LFA-1 antibodies followed by 5 microg G-CSF for 5 days than with G-CSF alone (119 +/- 34 days vs 17 +/- 14 days), indicating mobilization of repopulating stem cells. Pretreatment with blocking antibodies to intercellular adhesion molecule-1 (ICAM-1; CD54), a ligand of LFA-1 and Mac-1, did not result in an effect on G-CSF-induced mobilization, suggesting that the enhancing effect required an interaction of the beta 2 integrins and one of their other ligands. Enhancement of mobilization was not observed in LFA-1-deficient (CD11a) mice, indicating that activated cells expressing LFA-1 mediate the synergistic effect, rather than LFA-1-mediated adhesion.     

Differential expression of LFA-1 molecules in non-Hodgkin's lymphoma and lymphoid leukemia

We investigated the expression of adherence molecules lymphocyte function-associated antigens-1 alpha and -beta (LFA-1 alpha, -beta) and p150, 95 in 103 well-characterized non-Hodgkin's lymphomas (NHLs) and lymphoid leukemias (LLs). We found that NHLs and LLs differentially express LFA-1 molecules according to their lineage derivation, degree of clinical aggressiveness, and anatomic site of involvement. Specifically, (a) T-cell neoplasms nearly always express these molecules; (b) diffuse aggressive B-cell NHLs and mature LLs often lack LFA-1 alpha molecules; and (c) B-cell chronic lymphocytic leukemia (CLL) is often LFA-1 alpha-negative while B-cell small lymphocytic lymphomas (SLLs) are nearly always LFA-1 alpha-positive. Furthermore, the low expression of LFA-1 alpha in CLL is related to the low degree of homotypic lymphocyte adhesion after tumor promoter antigen stimulation that does not modulate the expression of LFA-1 alpha in vitro. The differential expression of LFA-1 by B-cell CLL and SLL and their degree of homotypic lymphocyte adhesion may account for the distinct anatomic compartmentalization and characteristic clinical behavior of these two morphologically and immunologically similar lymphoid malignancies.     

Discordant LFA-1/ICAM-1 expression in a case of secondary plasma cell leukemia associated with subcutaneous plasmacytoma

We observed a unique case of multiple myeloma that was transformed into plasma cell leukemia presenting with subcutaneous and soft tissue infiltrates. Subcutaneous and minor pelvic soft tissue plasmacytomas and the leukemic transformation were diagnosed in a 72-year-old woman after she had completed 9 months of chemotherapy for IgG k multiple myeloma. Immunophenotypic study revealed that leukemic cells in her peripheral blood were positive for ICAM-1 (CD54) but negative for LFA-1 α (CD11a) and LFA-1 β (CD18), whereas infiltrating leukemic cells in the subcutaneous plasmacytoma of the left thigh were positive for LFA-1 α and LFA-1 β but negative for ICAM-1. In addition, intermingling capillary endothelial cells were positive for ICAM-1. Extramedullary soft tissue plasmacytoma is uncommon in association with plasma cell tumors, and the exact mechanism of the development of plasmacytoma is not known. In the present case, however, the discordant expression of LFA-1/ICAM-1 adhesion molecules may have accounted for the distinct patterns of growth and the spread of the subcutaneous plasmacytoma through homing of the LFA-1 α⁺, LFA-1 β⁺ leukemic cells to ICAM-1 endothelial cells. © 1993 Wiley-Liss, Inc.     

Splenectomy of rats selectively reduces lymphocyte function-associated antigen 1 and intercellular adhesion molecule 1 expression on B-cell subsets in blood and lymph nodes.

Splenectomy increases the number of B cells in the blood of humans and animals. It is unknown whether this is due to changes in migration, proliferation, or both. The numbers of na?ve (IgD(+)IgM(+)), memory (IgD(-)IgM(high)), newly formed (IgM(high)CD90(high)), early recirculating follicular (IgM(low)CD90(high)), recirculating follicular (IgM(low)CD90(-)), and marginal zone (IgM(high)CD90(-)) phenotype B cells were determined in control and splenectomized rats by flow cytometry. All subsets increased significantly in the blood after splenectomy. Because surface molecules are involved in the regulation of migration and proliferation, their expression (lymphocyte function-associated antigen 1 [LFA-1], intercellular adhesion molecule 1 (ICAM-1), L-selectin, alpha4-integrins, CD44, major histocompatability complex class II, interleukin 2 receptor-alpha chain) was determined on B- and T-cell subsets of both groups. B cells, but not T cells, showed a significantly reduced LFA-1 and ICAM-1 expression in blood and lymph nodes, whereas the expression of the other surface molecules analyzed remained unchanged. The down-regulation of these molecules did not influence the adherence of B cells to high endothelial venules in vitro. In vivo, however, ICAM-1(low)-expressing B cells migrated significantly faster through lymph nodes (ICAM-1(low) 41 +/- 5 hours versus ICAM-1(high) 58 +/- 3 hours), whereas proliferation of B cells in bone marrow, lymph node, and blood remained unchanged. Thus, the presence of one organ is necessary for appropriate expression of LFA-1 and ICAM-1 on B cells in other, distant organs. The more rapid transit of ICAM-1(low) B cells through lymph nodes may be responsible for the increased B-cell number in the blood after splenectomy.     

Enhanced T-lineage acute lymphoblastic leukaemia cell survival on bone marrow stroma requires involvement of LFA-1 and ICAM-1

The bone marrow (BM) microenvironment supports leukaemia cell survival and proliferation. The roles played by adhesive receptor interactions in the survival of T-lineage acute lymphoblastic leukaemia (T-ALL) cells on BM stromal cells are not well understood. Recently, we have developed an assay that partially recapitulates the BM microenvironment using HS-5 BM stromal cells. In this assay, the magnitude of ex vivo T-ALL lymphoblast survival predicts patient outcome. We examined the molecular basis for cell-cell adhesive events leading to T-ALL lymphoblast survival on HS-5 and on donor-derived BM stroma. Lympho cyte function-associated antigen-1 (LFA-1) on T-ALL cell lines bound intercellular adhesion molecule-1 (ICAM-1) on HS-5 monolayers, and survival was inhibited 85-98% with monoclonal antibodies directed against LFA-1 or ICAM-1. We compared these results with patient-derived T-ALL lymphoblasts co-cultured on either HS-5 BM or normal BM monolayers and found that LFA-1 and ICAM-1 were required, but not alone sufficient for ex vivo leukaemic cell survival. On normal BM stroma, but not HS-5 monolayers, two additional adhesion molecules, vascular cell adhesion molecule-1 (VCAM-1) and E-selectin, were highly expressed and contributed to T-ALL cell survival. This is the first report to demonstrate the importance of LFA-1/ICAM-1-mediated adhesion as a critical event in a cascade of cell surface receptor-ligand interactions that regulate T-ALL survival in the BM microenvironment.     

Effects of Th1 and Th2 cytokines on cytokine production and ICAM-1 expression on synovial fibroblasts.

OBJECTIVES--To investigate the influence of the Th1 and Th2 lymphokines interleukins (IL)-4 and IL-13, interferon gamma (IFN gamma), and several monokines on the adhesion of mononuclear cells to synovial fibroblasts and intercellular adhesion molecule-1 (ICAM-1) expression and cytokine production of synovial fibroblasts in patients with osteoarthritis. METHODS--Synovial fibroblasts were isolated from patients with osteoarthritis and stimulated with IL-1 beta, IL-4, IL-6, IL-10, IL-12, IL-13, tumour necrosis factor alpha (TNF alpha), and IFN gamma. Subsequently, we determined the production of IL-1 alpha, IL-1 beta, IL-6, IL-10, IL-12, IFN alpha and TNF alpha, and the expression of ICAM-1 lymphocyte function associated antigen 3 (LFA-3), BB7, and major histocompatibility complex class II molecules on these cells. Furthermore, the adhesion of freshly isolated mononuclear cells from the peripheral blood was tested using a colourimetric cell-cell adhesion assay. RESULTS--Only production of IL-6 and the expression of ICAM-1 were observed. IL-1 beta and TNF alpha were the most potent stimulatory mediators of both cytokine production and ICAM-1 expression. IL-4 and IL-13 had differential effects as they upregulated cytokine production but downregulated IFN gamma induced ICAM-1 expression. In functional adhesion assays, TNF alpha, IL-1 alpha and, to a lesser extent, IFN gamma led to increased adhesion of mononuclear cells, whereas IL-4 and IL-13 had no effect. CONCLUSIONS--Our data indicate that Th1 and Th2 lymphokines can modulate the function (cytokine production and expression of adhesion molecules) of synovial fibroblasts.     

B-cell homotypic adhesion through exon-A restricted epitopes of CD45 involves LFA-1/ICAM-1, ICAM-3 interactions, and induces coclustering of CD45 and LFA-1

Lymphocyte interactions with other leukocytes and other cell types, as well as with components of the extracellular matrix, are one of the key steps in the immune response. Three novel monoclonal antibodies (MoAbs) have been produced and selected for their ability to induce intercellular adhesion in B cells. These three MoAbs immunoprecipitated a polypeptide of 220 kD, displaying specific phosphotyrosine phosphatase activity that has been identified as CD45. These MoAbs recognize epitopes located on the alternative spliced exon-A-encoded region of CD45. These epitopes are of polypeptidic nature, but they can be masked by addition of carbohydrate during CD45 biosynthesis. Interestingly enough, CD45 epitopes recognized by these MoAbs appeared to be selectively expressed on both peripheral blood and tonsillar B lymphocytes as well as on peripheral blood natural killer (NK) cells. CD45-mediated intercellular adhesion was abrogated upon incubation with anti-leukocyte function-associated antigen 1 (anti-LFA-1), intercellular cell adhesion molecule 1 (ICAM-1), and ICAM-3 MoAbs, thus indicating that this phenomenon involved both LFA-1/ICAM-1 and LFA- 1/ICAM-3 cell adhesion pathways. Moreover, CD45-mediated cell aggregation was also inhibited by preincubation with some conventional anti-CD45 MoAbs. Interestingly, the triggering of cell aggregation through CD45 induced membrane surface relocation of CD45 and LFA-1 molecules, with both of them colocalizing at cell-cell contact areas of B-cell aggregates. Studies with inhibitors of both phosphotyrosine phosphatase and tyrosine kinase activities suggest that CD45 phosphotyrosine phosphatase activity could be involved in CD45-mediated cell aggregation. Taken together, these results support the notion that CD45 is a key molecule in the regulation of LFA-1-mediated cell-cell interactions.     

Impaired transendothelial migration by neonatal neutrophils: abnormalities of Mac-1 (CD11b/CD18)-dependent adherence reactions

In order to evaluate the functions of lymphocyte function antigen-1 (LFA-1) (CD11a/CD18) and Mac-1 (CD11b/CD18) on neonatal neutrophils, we examined neutrophil adhesion to and migration through human umbilical vein endothelial cell (HUVEC) monolayers in vitro. Transendothelial migration of adult neutrophils was greatly enhanced by preincubation of HUVEC with interleukin-1 (IL-1). This migration was significantly inhibited by monoclonal antibodies (MoAbs) against LFA-1 (CD11a) and Mac-1 (CD11b) subunits. Migration of neonatal neutrophils was markedly diminished compared to adult neutrophils, and MoAbs against LFA-1 further reduced migration. In contrast, anti-Mac-1 MoAb was not inhibitory. Adhesion of adult neutrophils was significantly enhanced by prestimulation of HUVEC with IL-1, and was significantly inhibited by MoAbs against LFA-1. Adhesion of neonatal neutrophils was near adult levels and comparably inhibited by anti-LFA-1 MoAb. In addition, adhesion of neonatal and adult neutrophils to purified ICAM-1 in artificial planar membranes was comparable and almost completely inhibited by anti-LFA-1 MoAb. Chemotactic stimulation induced Mac-1-dependent adhesion of adult neutrophils to endothelial cells, purified intercellular adherence molecule-1 (ICAM-1) and protein-coated glass. In marked contrast, adhesion of neonatal neutrophils to these substrates was not significantly increased by chemotactic stimulation. These findings indicate that diminished transendothelial migration by neonatal neutrophils is related to abnormal interactions of Mac-1 with ICAM-1 and possibly other endothelial ligands. These functional deficits may contribute to impaired inflammation and infectious susceptibility in human neonates.