ICAM-1 Antigen Research Articles

Interleukin-4 and interferon-gamma interactions in the induction of intercellular adhesion molecule-1 and major histocompatibility complex class II antigen expression of normal human keratinocytes.

Interleukin-4 (IL-4) that may be produced by T-helper cells in atopic lesions has immunomodulatory activities on skin cells which are poorly known. Our study was aimed at determining whether the cytokine exerts some effects on keratinocyte activation and can either enhance or antagonize interferon-gamma (IFN-gamma)-induced ICAM-1 or HLA-DR antigen expression. Using normal keratinocytes cultured in defined medium and cytofluorography, we showed that treatments of the human cells with the cytokine IL-4 alone had no effect on the induction of ICAM-1 or HLA-DR molecules. However, a transient, but significant enhanced expression of ICAM-1 was observed by the combination of IFN-gamma and IL-4 after 24 h of stimulation, which was followed by a reduction at 48 and 72 h. Conversely, IL-4, when added during the IFN-gamma activation stage, had no effect on MHC class II antigen expression of keratinocytes; however, the cytokine reduced the expression of these antigens when added 24 h before the stimulation by IFN-gamma. These results suggest that IFN-gamma and IL-4 may interact to regulate ICAM-1 and HLA-DR expression on keratinocytes.

Interleukin-10 inhibits the primary allogeneic T cell response to human epidermal Langerhans cells.

In this study, we analyzed the effect of interleukin-10 (IL-10) on the primary allogeneic T cell response induced by human Langerhans cells (LC), the dendritic cells from epidermis. We showed that IL-10 strongly inhibited the T cell response, provided it was added at the beginning of the mixed epidermal cell lymphocyte reaction (MELR). Proliferation of both CD4+ and CD8+ T cell subsets was affected by the cytokine. An inhibitory effect of IL-10 on human LC allostimulatory function was evidenced by the fact that IL-10-preincubated LC, but not IL-10-preincubated T cells, can display inhibitory effect. LC treatment with IL-10 partially inhibited the increase of HLA-DR expression on cultured LC as the percentage of highly positive HLA-DR cells was lower than that observed in the absence of the cytokine. IL-10 inhibited T cell alloreaction induced by 2-day-cultured human LC which constitutively display high levels of HLA class II, as well as ICAM-1 and LFA-3 antigens. This suggests that the suppressive effect of the cytokine was not merely related to an impaired up-regulation of these molecules. Addition of IL-1 during the MELR potentiated the allogeneic T cell proliferation and could reverse, at least partly, the inhibitory effect of IL-10. Collectively, these data indicate that IL-10 can prevent the alloreaction induced by human dendritic cells, providing new insights into the potential clinical use of this cytokine.

Production and characterization of mouse thymic epithelial cell clones.

Four thymic epithelial cell lines (TEC) were derived from neonatal CBA and non-obese diabetic (NOD) mouse thymus. From these cell lines a series of clones were produced by limit dilution and these have remained in stable culture for more than 1 year. Morphological characterization indicates that most cells are stellate with numerous short or long processes and ultrastructural studies show both active and quiescent cells with junctional complexes and bundles of tonofibrils. Immunohistochemical and flow cytometric analyses show that the cells express cytokeratin and appear to label for markers characteristic of cortical epithelial cells. Most clones express Thy-1, Pgp-1, ICAM-1, HSA and B220 antigen, but are negative for LFA-1, CD2, Mel 14, Fc receptor, Mac-1, CD4 and CD8. All clones express low to moderate levels of class I MHC but are either negative or extremely low for class II MHC antigen. Most clones secrete IL-6 and granulocyte-macrophage-CSF (GM-CSF) in vitro, but generally do not produce IL-2, IL-3, IL-4 or IFN-gamma.

ICAM-1 directs migration and localization of interstitial leukocytes in experimental glomerulonephritis

Recent studies of rat anti-GBM disease have demonstrated a functional role of the ICAM-1/LFA-1 interaction in the entry of leukocytes into the glomerulus and an association between interstitial ICAM-1 expression, leukocyte infiltration and tubulointerstitial damage. In the current study, we used immunogold ultrastructural techniques to identify ICAM-1/LFA-1 interactions in the initiation of interstitial leukocyte infiltration during the first 24 hours of rat accelerated anti-GBM disease. In normal rats, there was weak constitutive ICAM-1 expression in the interstitium: on the endothelial luminal surface of interstitial capillaries, venules and arterioles, on the entire surface of interstitial fibroblast-like cells and confined to the brush border of proximal tubules. As early as 1.5 hours after injection of anti-GBM serum, there was a marked increase in the intensity of ICAM-1 expression, most notably on capillary endothelium, fibroblast-like cells and brush borders of proximal tubules, particularly in the periglomerular/perihilar areas. Mononuclear leukocytes exhibiting strong surface LFA-1 (CD11a and CD18) expression were seen adherent to the endothelium of interstitial capillaries, with ICAM-1 and LFA-1 antigens present at sites of contact. In addition, mononuclear cells migrating into the interstitium showed areas of close apposition to interstitial fibroblast-like cells, and here ICAM-1 and LFA-1 expression were also prominent at the sites of contact. This is the first study to demonstrate sites of ICAM-1/LFA-1 interaction in mononuclear cell migration and localization in glomerulonephritis. The results suggest that up-regulation of periglomerular/peritubular capillary ICAM-1 expression is important for mononuclear cell entry into the interstitium, while interaction with fibroblast-like cells may facilitate movement and subsequent focal accumulation of mononuclear cells at sites within the interstitium.

Pivotal Role of Endogenous TNF-α in the IL-2-Driven Activation and Proliferation of the Functionally Immature NK Free Subset

Highly purified peripheral blood-derived NK cells can be separated into three functionally defined subpopulations, namely, non-target binding free cells, binders, and killers. The free cell subset is the least mature and was examined for its response to IL-2-mediated activation and the role of endogenous secretion of TNF-α in its maturation and differentiation. The findings demonstrate that endogenous TNF-α secretion is prerequisite for the initiation of IL-2-mediated activation of free cells into killer cells. The addition of IL-2 to free cells upregulated the surface expression of IL-2R (TAC), TNF-R (p75), CD69, and ICAM-1 antigens and also stimulated cell proliferation. Furthermore, the addition of IL-2 to free cells resulted in the induction of cytotoxic activity and stimulation of free cells to become binder and killer cells. All of these IL-2-mediated manifestations are shown to be downregulated by the addition of anti-TNF-α antibody. However, IL-2-mediated TNF-α secretion was not affected by the addition of anti-TNF-α antibody. The specificity of the anti-TNF-α antibody-mediated inhibition was corroborated by the failure of the antibody to inhibit interferon-α-mediated activation of free cells into killer cells. Most of the events associated with the inhibitory activity of anti-TNF-α antibody were mimicked by the addition of IL-4 to IL-2-treated free cells. These findings suggest that the IL-2-mediated maturation and differentiation of the immature free cells to become cytotoxic and proliferate are the result of a sequence of events that are initiated by the secretion of endogenous TNF-α.

Expression of adhesion molecules by endothelial cells of early human decidua.

The expression of adhesion molecules by endothelial cells (EC) of early human decidua was studied with monoclonal antibodies and the immunoperoxidase technique. Although E-selectin, INCAM-110 and VCAM-1 were poorly detected on decidual EC, ICAM-1, P-selectin and DR antigens were highly expressed by these cells, some of which showed high endothelial venule-like morphology. Our results suggest that decidual EC are activated, and are probably involved in the active recruitment of leucocytes.

Identical expression of ELAM‐1, VCAM‐1, and ICAM‐1 in sarcoidosis and usual interstitial pneumonitis

Extravasation of leucocytes in tissues is mediated by leucocyte-endothelial cell interactions in which adhesion molecules play an important role. Until now, two pathways have been unravelled, i.e., the LFA-1/ICAM-1 and the VLA-4/VCAM-1 pathways. ELAM-1 has been shown to be involved in granulocyte accumulation and recently also in lymphocyte migration. The role of HECA-452 is under investigation. In this study we have investigated the expression of the above-mentioned adhesion molecules in lung tissue of patients with pulmonary sarcoidosis and usual interstitial pneumonitis (UIP), and in mediastinal lymph nodes of patients with sarcoidosis. ICAM-1 (CD54) was broadly distributed on the endothelium of all the vessels found in sarcoidosis and UIP. VCAM-1 was present on the endothelium of the venules, capillaries, and arterioles in both sarcoidosis and UIP. ELAM-1 reacted with endothelial cells lining venules and capillaries in chronic progressive sarcoidosis and in the active phase of UIP but not in the stationary phases of both diseases. HECA-452 activity could be detected only on high endothelial venules within sarcoid lymph nodes. In lung tissues, macrophages bearing the ICAM-1 antigen were present in sarcoid tissue but not in the interstitium and alveolar space of UIP. LFA-1 (CD11a/CD18) and VLA-4 (CD49d/CD29) were present on all leucocytes found but seemed to be more highly expressed on lymphocytes in sarcoidosis. These findings suggest that the LFA-1/ICAM-1 and VLA-4/VCAM-1 pathways are involved in leucocyte migration in both types of lung disease, while in the active phases of sarcoidosis and UIP, ELAM-1 is also involved.

Transfer of the IL-6 gene into a human colorectal carcinoma cell line and consequent enhancement of tumor antigen expression

cDNA encoding the human IL gene (580 bp), inserted into a retroviral expression vector carrying neomycin resistance selective marker, was introduced into HT-29 human colon carcinoma cells by lipofection. Interleukin-6 activity was measured by ELISA and bioassay using B9 cells. Interleukin-6 secreted by transfected HT-29 cells was shown to be biologically active. The expression of the human tumor associated antigen CEA (carcinoembryonic antigen), HLA classes I and II, and ICAM-1 antigens in the transfected HT-29 cells were also analyzed by flow cytometry. Significant enhancement in the expression of CEA but not in the expression of HLA class I, HLA class II and ICAM-1 antigens, was observed in the transfected HT-29 cells as compared to the parental HT-29 cells. These results provide experimental evidence that enhancement of tumor antigen expression on tumor cells can be induced by IL-6 gene transfection, and suggest another potential role for the use of IL-6 gene transfer in the immunotherapy of human cancers.

The effects of tumor necrosis factor (TNF) derivatives on TNF receptors

The pleiotropic cytokine TNF has been implicated in the regulation of many immune and inflammatory responses in vivo, and in addition exerts a wide range of effects on target cells in vitro. However, although two cell surface receptors for TNF have been identified, and their cDNAs cloned, the amino acid residues necessary for the biological activity of TNF have not been characterized. We have therefore constructed derivatives of TNF termed ‘muteins’, in which the first 3 to 7 amino acids of native TNF-α have been replaced, using synthetic cDNA expressed in E. coli. In the present study we compare the effects of native TNF-α and muteins III, IV, V and VI in several different in vitro systems and in one in vivo model. We observed binding to the p75 TNF receptor on Jijoye Burkitt lymphoma cells with native TNF-α and mutein III alone, whereas the p55 TNF receptor on the human epithelioid carcinoma cell line HeLa bound TNF-α, mutein III and mutein V. Muteins IV and VI failed to recognize either TNF receptor. WEHI 164 fibrosarcoma cells were killed by muteins III, V and VI. Human umbilical vein endothelial cells responded to native TNF-α and to muteins III, IV and V, but not to mutein VI, by increasing the surface expression of ICAM-1 antigen and secretion of the cytokines GM-CSF and IL-6. All four compounds were pro-inflammatory in a mouse in vivo model. The results presented in this report confirm that N-terminal amino acids are critical for both receptor binding and biological activity of TNF-α. Amino acid substitution in the N-terminal region of the TNF-α molecule may provide an insight into the mechanism of TNF-α receptor binding, and further elucidate the structural requirements for its biological activity.

Immunohistochemical analysis of cell surface markers in leprosy patients

Nine biopsy specimens from 3 tuberculoid (TT), 1 borderline tuberculoid (BT), 2 borderline (BB), 2 borderline lepromatous (BL), and 1 lepromatous (LL) patients were studied using immunoperoxidase procedures with monoclonal antibodies. In TT patients 4B4+, TCR alpha beta+, CD4+ T cells were dominant in dermal granulomas. In LL patient, dermal granulomas with 4B4+, TCR alpha beta+, CD4+ T cells and 2H4+, TCR alpha beta+, CD4+ T cells also had CD8+ T cells. The proportion of 4B4+ T cells increased in granulomas from LL to TT and 2H4+ T cells proportionately increased from TT to LL. TCR gamma delta+ T cells were detected only in BB and BL patients. However, there is no difference of staining pattern of ICAM-1 or LFA-1 antigen in any type of leprosy. These results indicate that the immunohistochemical pattern of T cells (CD4, CD8, 4B4, 2H4, TCR) may be useful in the diagnosis of the spectrum of leprosy.

Induction of vascular adhesion molecules during rejection of human cardiac allografts.

Adhesion of leukocytes to vascular endothelium is a necessary step leading to the migration of cells into underlying tissues. Vascular adhesion molecules regulate this process and may play an important role in graft rejection. Immunocytochemical studies have been used to investigate the expression of vascular adhesion molecules (ICAM-1, PECAM, VCAM-1, and ELAM-1) in normal donor heart (n = 15) and myocardial biopsies from heart transplant patients with acute rejection (n = 15). Sections were also stained with antibodies against endothelium, leukocytes, MHC antigens, and markers of cell activation. In donor heart EN4, vWF, ICAM-1, PECAM, MHC class I--and, to a lesser extent, VCAM-1 and DR antigen--are expressed on arterioles and venules, whereas ELAM-1 and Pal-E are restricted to venules. Expression of Pal-E, VCAM-1, ICAM-1, and DR antigen was increased during rejection. Capillary endothelium normally expresses EN4, ICAM-1, PECAM, MHC class I, and DR antigen but little, if any, VCAM-1 or ELAM-1. During rejection, however, there is an increased expression of all adhesion molecules. This is paralleled by an increased expression of vWF by capillary endothelium. In addition, ICAM-1 like MHC class I antigen is induced on the myocardial membrane and intercalating discs. Endocardium from donor heart expresses EN4, vWF, PECAM, MHC class I, and sometimes Pal-E and ICAM-1, but very little VCAM-1, ELAM-1 or DR antigen. There is an increased expression of Pal-E, ICAM-1, VCAM-1, and DR antigen on endocardium from rejecting heart biopsies. Proliferating Ki-67+ cells and activated T cells expressing the receptor for IL-2 were also found in biopsies during rejection episodes.

Erythema multiforme: pathomechanism of papular erythema and target lesion.

Skin lesions of erythema multiforme show time-dependent changes from early papular erythema to the late target lesion which consists of a peripheral elevated erythematous area and a central depressed area. We investigated the pathomechanism of erythema multiforme, by examining the papular erythema and target lesion separately. In the early papular erythema, a small number of polymorphonuclear leukocytes and nuclear debris were seen intermingled with mononuclear cells around the slightly swollen blood vessels, on which immunoglobulin and complement components were deposited. Circulating immune complex levels were occasionally elevated. Sera from the patients generated high levels of reactive oxygen species and nitroblue tetrazolium test revealed positive reaction on the infiltrating cells around the blood vessels. These findings suggest that the papular erythema develops via incomplete type III allergic reaction, followed by damage through reactive oxygen species. In the target lesion, the activity of histamine-N-methyltransferase, which is the major histamine-degrading enzyme, was markedly decreased in the peripheral elevated erythematous area and it was recovering in the central clearing area. ICAM-1 and HLA-DR antigens were expressed on the surfaces of the keratinocytes. An increased number of epidermal Langerhans cells and CD4 cell infiltration were observed in the peripheral elevated erythematous area, while a decreased number of epidermal Langerhans cells and CD8 cell infiltration in the central depressed area were observed. These findings suggest that impaired histamine metabolism and cellular allergic reactions play important roles in the development of the target lesion.

NIT-1, a Pancreatic β-Cell Line Established From a Transgenic NOD/Lt Mouse

NOD/Lt mice harboring a hybrid rat insulin-promoter/SV40 large T-antigen gene spontaneously develop beta-cell adenomas. NIT-1 is a pancreatic beta-cell line established from one of these transgenic mice. Immunocytochemical staining of passage 18 cells showed most contained insulin, with less than 5% containing glucagon, and none containing pancreatic polypeptide or somatostatin. Glucagon content radioimmunoassayed in cell extracts was only 0.27% of the insulin content. Two-hour insulin secretion at 16.5 mM glucose was 638 ng/10(6) cells (41% of intracellular content) compared to only 1.3 ng glucagon (32% of intracellular content). Stimulated insulin secretion was consistently observed in response to 11 and 16.5 mM glucose between passages 11 and 19. At passage 19, both theophylline and tolbutamide stimulated insulin secretion at 5.5 mM glucose. Northern-blot analysis confirmed high levels of insulin mRNA but only trace glucagon mRNA and undetectable somatostatin mRNA. Interferon-gamma (IFN-gamma)-induced MHC class I RNA expression was correlated with markedly increased antigen expression at the cell surface. Similarly, a MHC-linked "occult" class I-like antigen detected by Cr release assay only after exposure of standard NOD/Lt islet cells to IFN-gamma was strongly induced by IFN-gamma in NIT-1 cells. Cell surface MHC class II antigen was not constitutively expressed on NIT-1 cells and could not be detected after IFN-gamma incubation, despite demonstration of IFN-gamma-induced Aa, Ab, and Li invariant-chain RNA transcripts. Similarly IFN-gamma induction of intercellular adhesion molecule 1 (Icam-1) transcripts was not accompanied by demonstrable cell surface expression of ICAM-1 antigen.(ABSTRACT TRUNCATED AT 250 WORDS)

ICAM-1 EXPRESSION ON EPIDERMAL KERATINOCYTES IN CUTANEOUS GRAFT-VERSUS-HOST DISEASE

An immunohistological study of epidermal keratinocytes for the intercellular adhesion molecule, ICAM-1 (CD54), was undertaken on skin biopsies from allogeneic bone marrow transplant recipients. In control biopsies from normal donors and patients prior to transplantation, staining was weak and confined to relatively few cells. After transplantation there was a significant increase in both the number of positive cells and their staining intensity in biopsies showing histological evidence of GVHD but not in those exhibiting normal appearances or epidermal abnormalities that could be attributed to cytotoxic drugs or irradiation. There was a strong positive correlation between ICAM-1 and HLA-DR expression by keratinocytes. All cases exhibiting increased ICAM-1 also exhibited an increase in HLA-DR antigens. The converse was not true, however, as 6 biopsies exhibited HLA-DR positivity without detectable increases in ICAM-1. Both ICAM-1 and HLA-DR antigen synthesis may be stimulated by local cytokine release following interactions between donor and recipient cells in the early posttransplant period. Our present findings suggest that immunostaining for ICAM-1 has little value in the early diagnosis of cutaneous GVHD but further, more detailed prospective studies would be of value.

Interleukin 4 promotes expression of mast cell ICAM-1 antigen.

Cell recognition molecules play a crucial role in the regulation of immune cells. We recently found that mast cells (MCs) express leukocyte recognition molecules, including ICAM-1 antigen, a natural ligand of LFA-1. We here report that interleukin 4 (IL-4), a pleiotropic cytokine and mast cell differentiation factor, selectively promotes expression of surface ICAM-1 antigen and ICAM-1 mRNA in human MCs. IL-4 also up-regulates ICAM-1 antigen in cells of monocyte/macrophage lineage but has no effect on ICAM-1 antigen expressed on basophils, fibroblasts, or lymphocytes. The increase in expression of mast cell/macrophage ICAM-1 antigen induced by IL-4 may contribute to the accumulation of leukocytes and facilitate cell-contact-dependent regulation of immune cells in inflamed tissues.

Characterization of the rat leukocyte integrin, CD11/CD18, by the use of LFA-1 subunit-specific monoclonal antibodies.

We have attempted to characterize the rat leukocyte integrin, CD11/CD18, by the use of newly generated monoclonal antibodies (mAb) WT.1 (anti-CD11a) and WT.3 (anti-CD18) in conjunction with an mAb, OX42, reactive with a rat integrin-like molecule, with respect to the biochemistry, cellular distribution and function. The conclusion that the mAb WT.1 and WT.3 specifically recognize the rat CD11a and CD18, respectively, was based on: (a) their ability to inhibit homotypic aggregation of splenic concanavalin A (Con A) blasts; (b) sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the antigens recognized; (c) their ability to inhibit binding of Con A blasts to the purified ligand, namely the ICAM-1 antigen and (d) their blocking abilities in mixed leukocyte reaction. In the rat, CD18 has an apparent molecular mass of 95-100 kDa and can associate with at least three distinct alpha subunits of 160-170 kDa (CD11a), 140-150 kDa and 120-130 kDa. The latter two are precipitated by OX42 from M phi but not from unstimulated lymphocytes. They presumably represent the rat CD11b and CD11c, respectively. Rat thymocytes, PBL, thoracic duct lymphocytes, monocytes and neutrophils expressed differential levels of CD11a and CD18. Peritoneal M phi showed virtually no CD11a expression, although CD18 was expressed at levels similar to those seen on blood monocytes, showing an interesting pattern of LFA-1 expression regulation in this cell lineage. Both WT.1 (anti-CD11a) and WT.3 (anti-CD18) apparently recognize a "low-affinity" as well as a "high-affinity" form of LFA-1 and do not discriminate between the two.

Differences in Non-MHC Restricted Cytotoxic Activities of Human Peripheral Blood Lymphocytes after Transfusion with Allogeneic Leukocytes or Platelets Possessing Class I and/or Class II MHC Molecules

MHC-unrestricted cytotoxic activity of peripheral blood lymphocytes (PBL) from 4–6 healthy donors was investigated before and after transfusion with allogeneic leukocytes or platelets. Natural killer and lectin-dependent cellular cytotoxicity (LDCC) of PBL was tested against K562 and Raji target cells in a 4-h and 16-h 51Cr-release assay, respectively. After allotransfusion with leukocytes, we found increased cytotoxic activity of each donor's PBL against all the three targets on day 3 or 7. The highest non-specific cytotoxic activity was detected against the relatively NK resistant Raji target cells. The increase of cytotoxic activity was lowest against the LDCC target (PHA-treated Raji) cells. On the contrary, no changes in cytotoxic activity against any targets were observed after allotransfusion with platelets (possessing class I HLA antigens but no HLA class 11 molecules). Our results suggest that HLA class II molecules, presumably by inducing immune responses, are essential for activation/generation of non-specific killing of tumor targets after leukocyte transfusion. Thrombocytes, known to be less immunogenic than leukocytes, are not effective in in vivo enhancing of non-specific cytotoxicity. Cellular activation of PBL following leukocyte allotransfusion was confirmed by detection of elevated serum neopterin and β-2-micro globulin levels on day 3. This was not the case after platelet allotransfusion. In addition, the expression of ICAM-1 antigen (as a molecule involved directly in MHC-unrestricted cytotoxicity) was also found to be increased in two donors' PBL on day 3 after leukocyte transfusion in contrast to transfusion with platelets.

Human melanoma cells with high susceptibility to cell‐mediated lysis can be identified on the basis of icam‐1 phenotype, vla profile and invasive ability

Marked heterogeneity for susceptibility to lysis by autologous CTL clones and allogeneic IL-2-activated CD3- and CD3+ lymphocytes was found among 19 clones isolated from a human metastatic melanoma (Me665/2). A subset of 5 clones with the highest susceptibility to lysis had increased ICAM-1 antigen expression. Phenotype analysis for the presence of extracellular matrix receptors in the beta 1- and beta 3-integrin families revealed that the tumor clones with the highest susceptibility to lysis were also characterized by frequent expression or increased expression of multiple receptors in the beta 1 family including VLA-1, -2, -3, -4 and -6. The correlation between phenotypic markers and susceptibility to lysis, seen at the clonal level, was confirmed by selection experiments on the uncloned metastasis Me665/2. In fact, the neoplastic population surviving 3 cycles of immunoselection with IL-2-activated lymphocytes exhibited, in comparison to the unselected metastasis: (1) reduced susceptibility to lysis and (2) reduced expression of ICAM-1 and of VLA antigens. In contrast, enhanced susceptibility to lysis and up-regulation of ICAM-1, VLA-1 and VLA-3 antigens were observed on melanoma cells recovered after invading a reconstituted basement membrane. These data indicate that melanoma cells with enhanced susceptibility to cell-mediated lysis can be identified on the basis of phenotypic characteristics (ICAM-1 and VLA antigen profile) and functional features (invasive ability on reconstituted basement membranes).

Induction of Human Thyroid Cell ICAM-1 (CD54) Antigen Expression and ICAM-1-Mediated Lymphocyte Binding*

To further understand the mechanism of lymphocyte accumulation within the thyroid gland in autoimmune thyroid disease we have examined the expression, regulation, and functional significance of the intercellular adhesion molecule-1 (ICAM-1, CD54) in human thyroid monolayer cells and immortalized thyroid cell clones. Human thyroid monolayer cells derived from both normal and abnormal human thyroid tissue showed low basal expression of the ICAM-1 antigen by flow cytometric assessment (mean % +/- SD positive cells = 13.7 +/- 6.1) compatible with the presence of ICAM-1 positive nonthyroid cells within the monolayer cultures. However, thyroid cell ICAM-1 antigen expression was further induced by exposure to recombinant human interferon-gamma (IF-gamma). At 100 U/ml, IF-gamma induced ICAM-1 expression in 56.0 +/- 19.0% of thyroid monolayer cells. Even greater expression of ICAM-1 antigen was induced by IF-gamma in human fetal thyroid cell monolayers of high purity (up to 80% of ICAM-1 positivity) thyroid monolayers established from a patient with Graves' disease (up to 84%), and in two immortalized human thyroid cell clones, 12S and TAD-2 (up to 61%). Furthermore, dose-response curves for ICAM-1 and HLA-DR antigen induction by increasing concentrations of IF-gamma showed that ICAM-1 antigen gene induction was 10-fold more responsive to IF-gamma than the HLA-DR antigen gene. In order to explore the functional consequence of ICAM-1 antigen expression by thyroid epithelial cells we examined the binding of peripheral blood mononuclear cells to thyroid monolayer cells and immortalized thyroid cells. These studies revealed a preferential adhesion of human PBMC to IF-gamma-treated thyroid monolayers compared to untreated control monolayer cells. Furthermore, this IF-gamma-induced cell adhesion was specifically inhibited by monoclonal anti-ICAM-1. These experiments demonstrate not only the capacity of human thyroid epithelial cells to express ICAM-1 antigen in the presence of a cytokine but, in addition, identify ICAM-1 antigen as responsible for enhanced T cell binding to thyroid epithelial cells. ICAM-1 antigen may, therefore, play an important role in T cell targeting and accumulation within the thyroid gland in autoimmune thyroid disease.

Further Characterization of Surface Membrane Structures Expressed on Human Basophils and Mast Cells

Recently, we were able to establish the immunologic surface marker profile of human basophils and mast cells. In the present study, the characterization of these cell types was extended by the use of monoclonal antibodies (mAbs) to hemopoietic differentiation antigens. Basophils and mast cells were enriched by mAbs and complement from chronic myeloid leukemia blood (n = 5) and dispersed lung tissue (n = 4), respectively. A panel of 80 mAbs was tested for being reactive with purified cell populations using flow cytometry and/or a combined toluidine blue-immunofluorescence staining procedure. In addition to previous findings, basophils were found to react with mAbs directed against the 126-kilodalton dipeptidylpeptidase IV (CD26), platelet glycoprotein IIa (CD31), CD40 antigen known to share sequence homology with nerve growth factor receptor, leukosialin (CD43), CD44 antigen, the ICAM-1 antigen (CD54) and VIM2-reactive gangliosides involving the sialofucooligosaccharide sequence (CDw65L). Bsp-1 was found to be a specific marker for human basophils, whereas mast cells were not stained by this reagent. Basophils apparently lack CD22 antigen, gangliosides detected by CDw65 mAbs (except CDw65L) and CD71 antigen (transferrin receptor). Mast cells were found to express CD43 and CD44 antigen. In contrast, mast cells lack CD22, CD26, CD31, CD40 and CDw65 antigen. These results provide further evidence that both blood basophils and mast cells express a unique immunologic surface marker profile including binding sites for a variety of immunomodulating ligands and adhesion molecules.