Interleukin-1 is a proinflammatory cytokine produced in glomerulonephritis. Blocking the action of interleukin-1 by the administration of the interleukin-1 receptor antagonist (IL-1ra) has been shown to prevent renal function impairment, reduce glomerular injury, inhibit leukocyte infiltration, and suppress tubulointerstitial damage in experimental antiglomerular basement membrane disease. A key mechanism in the entry of leukocytes into the kidney is the interaction between the interleukin-1 inducible intercellular adhesion molecule-1 (ICAM-1; CD54) and lymphocyte function-associated antigen-1 (CD11a/CD18). Therefore, this study investigated whether the inhibition of this mechanism was the means by which IL-1ra suppressed leukocyte infiltration in rat accelerated antiglomerular basement membrane glomerulonephritis. Disease was induced in two groups of six rats; animals were treated by constant sc infusion of recombinant human IL-1ra or saline from the initiation of disease until being euthanized 14 days later. In saline-treated animals, there was marked up-regulation of ICAM-1 in the glomerulus and interstitium, In which was associated with leukocyte infiltration. In particular, focal accumulation of CD11a+ and CD18+ cells was apparent in areas of tubulointerstitial damage exhibiting intense ICAM-1 expression. IL-1ra treatment partially reduced glomerular ICAM-1 expression and leukocyte infiltration. However, IL-1ra treatment resulted in a dramatic inhibition of interstitial ICAM-1 expression, interstitial leukocyte infiltration, and tubulointerstitial damage. In conclusion, this study has shown that interleukin-1 is a major inducer of ICAM-1 expression within the renal tubulo-interstitium--a process associated with focal leukocyte infiltration and tubulointerstitial damage.(ABSTRACT TRUNCATED AT 250 WORDS)

Semliki Forest virus A7 (SFV-A7) is a neurotropic alphavirus that leads to an asymptomatic encephalitis in adult immunocompetent mice. We studied the expression of leukocyte and endothelial cell adhesion molecules in the spleen and in the central nervous system (CNS) during SFV-A7 infection. Kinetics of the expression of LFA-1 alpha/CD11a, LFA-1 beta/CD18, Mac-1/CD11b, VLA-4/CD49d, ICAM-1/CD54 and L-selectin/CD62L was determined on splenic CD4+ and CD8+ T-cells and macrophages by flow cytometry. Time course of the expression of these antigens and VCAM-1/CD106 as well as viral antigens in the CNS was studied by immunoperoxidase staining. In the spleen, a sustained increase in LFA-1-expression and a temporary increase at day 7 in the expression of VLA-4, Mac-1 and ICAM-1 were detected on CD8+ T-cells. L-selection was down-regulated on CD4+ cells. Adhesion molecules on macrophages remained unchanged. In the CNS, expression of Mac-1+, VLA-4+ and LFA-1+ cells increased in parallel with the kinetics of the expression of their ligands ICAM-1 and VCAM-1 on brain vessels. Upregulation of adhesion of molecules peaked between days 5-8 and was most prominent in the cerebellar and brain stem white matter where viral antigens were most abundant. We conclude that the adhesion molecules profile of splenic T cells is altered during SFV-A7 infection which may influence their homing into the CNS. Macrophages are probably recruited non-specifically as a consequence of activation of the brain vascular endothelium in the inflamed areas of the brain.

Alloreactive T cells are involved in injurious graft rejection and graft-vs-host disease. However, they can also evoke beneficial responses to tumor Ags restricted by foreign MHC molecules. Manipulation of these alloreactivities requires information on the basis of T cell allorecognition. The vigorous T cell response to foreign MHC molecules may arise from peptide-independent recognition of polymorphic residues of foreign MHC molecules or peptide-specific recognition of novel peptides presented by foreign MHC molecules. We investigated CD8+ T cell allorecognition using recombinant HLA class I/peptide complexes. Peptide-specific allorecognition was examined using tetramers of HLA-A*0201 representing five peptides derived from ubiquitously expressed self-proteins that are known to bind endogenously to HLA-A*0201. Distinct subsets of CD8+ T cells specific for each HLA-A*0201/peptide combination were detected within four in vitro-stimulated T cell populations specific for foreign HLA-A*0201. Peptide-independent allorecognition was investigated using artificial Ag-presenting constructs (aAPCs) coated with CD54, CD80, and functional densities of a single HLA-A*0201/peptide combination for four different peptides. None of the four T cell populations specific for foreign HLA-A*0201 were stimulated by the aAPCs, whereas they did produce IFN-gamma upon stimulation with cells naturally expressing HLA-A*0201. Thus, aAPCs did not stimulate putative peptide-independent allorestricted T cells. The results show that these alloreactive populations comprise subsets of T cells, each specific for a self-peptide presented by foreign class I molecules, with no evidence of peptide-independent components.

Langerhans cells (LC) are key mediators of contact allergenicity in the skin. However, no in vitro methods exist which are based on the activation process of LC to predict the sensitization potential of chemicals. In this study, we have evaluated the performances of MUTZ-3, a cytokine-dependent human monocytic cell line, in its response to sensitizers. First, we compared undifferentiated MUTZ-3 cells with several standard human cells such as THP-1, KG-1, HL-60, K-562, and U-937 in their response to the strong sensitizer DNCB and the irritant SDS by monitoring the expression levels of HLA-DR, CD54, and CD86 by flow cytometry. Only MUTZ-3 and THP-1 cells show a strong and specific response to sensitizer, while other cell lines showed very variable responses. Then, we tested MUTZ-3 cells against a wider panel of sensitizers and irritants on a broader spectrum of cell surface markers (HLA-DR, CD40, CD54, CD80, CD86, B7-H1, B7-H2, B7-DC). Of these markers, CD86 proved to be the most reliable since it detected all sensitizers, including benzocaine, a classical false negative in local lymph node assay (LLNA) but not irritants. We confirmed the MUTZ-3 response to DNCB by real-time PCR analysis. Taken together, our data suggest that undifferentiated MUTZ-3 cells may represent a valuable in vitro model for the screening of potential sensitizers.

The human dermis contains a heterogeneous network of cells with a dendritic morphology, including factor XIIIa+ dermal dendrocytes and CD34+ dendritic cells located around epidermal adnexae. Whereas dermal dendrocytes have been immunohistochemically studied, CD34+ dermal cells have not yet been well characterized. We studied by simple and double immunolabeling techniques on tissue sections of normal human skin the phenotype of these cells and found them to express vimentin and Te7 but none of the remaining markers sought (factor XIIIa, von Willebrand factor, CD1a, CD3, CD4, CD8, CD14, CD25, CD36, CD45, CD54, CD56, LFA-1, EGF-R, S-100 protein, Mac 387, and muscle-specific actin). Rare CD34+ cells of the interstitial dermis expressed human leukocyte antigen (HLA)-DR antigens, but this was not the case for periadnexal CD34+ cells. These results show that CD34+ dendritic cells of human dermis are mesenchymal cells bearing a unique immunophenotype different from that of (myo)fibroblasts, monocytes-macrophages, Langerhans cells, and factor XIIIa+ dermal dendrocytes. Whereas the involvement of CD34+ cells in some cutaneous tumors is well known, their physiologic role in normal skin remains to be established. On the basis of our results, we speculate that these cells could represent uncommitted mesenchymal cells, unique by virtue of CD34 antigen expression.

Biochemical, genetic, and immunological studies of follicular dendritic cells (FDCs) have been hampered by difficulty in obtaining adequate numbers of purified cells in a functional state. To address this obstacle, we enriched FDCs by irradiating mice to destroy most lymphocytes, excised the lymph nodes, and gently digested the nodes with an enzyme cocktail to form single cell suspensions. The FDCs in suspension were selected using the specific mAb FDC-M1 with magnetic cell separation technology. We were able to get nearly a million viable lymph node FDCs per mouse at about 90% purity. When examined under light and transmission electron microscopy, the cytological features were characteristic of FDCs. Furthermore, the cells were able to trap and retain immune complexes and were positive for important phenotypic markers including FDC-M1, CD21/35, CD32, CD40, and CD54. Moreover, the purified FDCs exhibited classical FDC accessory activities including: the ability to co-stimulate B cell proliferation, augment antibody responses induced by mitogens or antigens, maintain B cell viability for weeks, and protect B lymphocytes from anti-FAS induced apoptosis. In short, this combination of methods made it possible to obtain a substantial number of highly enriched functional murine FDCs.

OBJECTIVE

Large numbers of plasma cells (PC) localise in the intestinal lamina propria (LP) where they play a critical role in the defence against pathogens. This study analyses the level of maturation reached by normal human colon LPPC in comparison with that of bone marrow (BM) PC.

METHODS

A technique was designed to purify LPPC by combining collagenase digestion of the mucosal layer and immunomagnetic selection of CD54(+) LP cells. It provided highly purified PC, as demonstrated by morphology, CD38(h) phenotype, and cytoplasmic IgA staining criteria. This procedure allowed comparison of in vitro functional capacities and a broad phenotypic analysis of BMPC and LPPC.

RESULTS

LPPC and BMPC exhibited identical expression of differentiation markers (CD19(-/+), CD20(-), HLA-DR(low/-), VS38c(high)), survival molecules (CD95 (low/-), Bcl-2(+)), and B cell transcription factor profile, as well as similar in vitro Ig secreting kinetics (14 days) and lack of susceptibility to apoptosis by CD95 ligation. In contrast, they markedly differed in adhesion molecule expression, as LPPC showed higher levels of CD44 and CD21 and were alpha 4 beta 7(+) whereas BMPC lacked this integrin and expressed higher levels of CD49d and CD31.

CONCLUSIONS

These data indicate that PC at effector sites of the humoral response (BM and LP) show similar high differentiation, survival, and functional features but display a distinctive pattern of adhesion molecules, probably related to their respective homing locations.

Human parainfluenza virus type 3 (HPIV3) causes bronchiolitis, pneumonia, and croup in newborns and infants. Several studies have implicated intercellular adhesion molecule-1 (ICAM-1) in inflammation during infection by viruses. In this study, we investigated the potential for HPIV3 to induce ICAM-1 in HT1080 cells. FACS analysis showed that HPIV3 strongly induced ICAM-1 expression in these cells. The ICAM-1 induction was significantly reduced when the virions were UV inactivated prior to infection, indicating that ICAM-1 induction was mostly viral replication dependent. Culture supernatant of HPIV3-infected cells induced ICAM-1 at an extremely low level, indicating that virus-induced cytokines played only a minor role in the induction process. Consistent with this, potent inducers of ICAM-1 such as IFN-gamma, TGF-beta, and TNF-alpha were absent in the culture supernatant, but a significant amount of IFN type 1 was present. By using U2A cells, which are defective in IFN type I signaling, we confirmed that ICAM-1 induction by HPIV3 occurred in a JAK/STAT signaling-independent manner. These data strongly indicate that HPIV3 induces ICAM-1 directly by viral antigens in a cytokine-independent manner; this induction may play a role in the inflammation during HPIV3 infection.

Fc gamma RIII (CD16), a low affinity FcR which binds IgG-containing immune-complexes, exists under membrane-associated forms and under a soluble form (sFc gamma RIII). The latter, present in biological fluids (serum, saliva), is generated by proteolytic cleavage of the two membrane-associated Fc gamma RIII isoforms, Fc gamma RIII-A (expressed by macrophages and NK cells) and Fc gamma RIII-B (expressed exclusively by neutrophils). Herein we demonstrate that dendritic cells (DCs), generated by culturing monocytes with GM-CSF and IL-4, bind biotinylated recombinant sFc gamma RIII. This binding is specific and involves the complement receptor CR3 (CD11b/CD18) and CR4 (CD11c/CD18). Indeed, preincubation of DCs with anti-CD11b and anti-CD11c mAbs decreased by 52% and 62% respectively the binding with sFc gamma RIII. Moreover, electron microscopy showed that binding of gold-labeled sFc gamma RIII to DCs maintained at 4 degrees C occurred within clathrin-coated pits. Once internalized, at 37 degrees C, sFc gamma RIII entered the endocytic pathway and reached the MHC class II compartments. Furthermore, DCs incubated for 48 h with multivalent sFc gamma RIII expressed increased levels of CD40, CD80, CD86, CD54, CD58, HLA class I and class II molecules and decreased levels of CD23 and CD32. These effects result in an increased capacity of DCs to trigger proliferative responses by CD4+ CD45RA+ allogeneic T cells. RT-PCR amplification demonstrated that incubation of DCs for 20 h in the presence of multivalent sFc gamma RIII induced the appearance of GM-CSF and IL-12 p40 mRNA. Among the cytokines constitutively expressed, IL-1 beta and IL-8 were strongly up-regulated whereas IL-6 and IL-12 p35 mRNA were increased to a lesser extent and the expression of MIP-1 alpha mRNA remained constant. Finally, ELISA tests demonstrated that DCs incubated with multivalent sFc gamma RIII secreted the cytokines IL-1 beta, IL-6, IL-8, GM-CSF and IL-12 p75. Thus, while becoming internalized sFc gamma RIII could affect the capacity of DCs to present antigens and, via the induction of accessory molecules and the release of the IL-12 p75 protein, could initiate Th1 type immune response.

BACKGROUND

The biological functions of basophils are precisely regulated by various cytokines in vitro, but little is known about surface markers that are upregulated during the cytokine-mediated activation process.

OBJECTIVE

It has been well established that CD69, CD44, and CD54 represent "activation markers" for cytokine-mediated eosinophil activation. The objective of this study was to elucidate the expression and regulation of these molecules in human basophils in vitro as well as in vivo.

METHODS

Basophils were purified from venous blood by means of density gradient centrifugation followed by negative selection. Surface expression was analyzed by means of flow cytometry. We also studied the expression of CD69, CD44, and CD54 on basophils in bronchoalveolar lavage fluid and blood specimens from patients with asthma.

RESULTS

CD44 and CD54 were constitutively expressed on basophils and moderately upregulated by IL-3. On the other hand, CD69 expression was only weakly observed in freshly isolated basophils, but IL-3 induced extremely high levels of expression. Surface CD69 appeared rather slowly in comparison with CD63 and CD11b, and the induction of expression was completed within 24 hours. Basophil CD69 had no functional relevance, but it did have biological relevance. Whole blood basophils from asthmatic individuals expressed significantly higher levels of CD69 than did those from normal individuals. Furthermore, bronchoalveolar lavage fluid basophils showed higher levels of CD69 expression than did blood basophils from the same donors.

CONCLUSIONS

CD69 expression on basophils was preferentially and strongly upregulated by IL-3. CD69 on basophils might be useful as an in vitro as well as in vivo marker of activation of these cells by IL-3.

OBJECTIVE

Despite the importance of dendritic cells in stimulating primary and secondary immune responses by presenting antigens to T-lymphocytes in draining lymph nodes and peripheral tissues, respectively, very limited information is available on the presence and localization of these cells in hepatitis C virus (HCV)-related chronic active hepatitis. Therefore, we addressed the ultrastructure, immunophenotype, distribution and relationships to lymphatics of dendritic cells in portal infiltrates of this disease.

RESULTS

Part of percutaneous diagnostic liver biopsies (Knodell's histological assessment index: 9-13) was processed for electron microscopy and for immunohistochemical detection of immune system cell membrane antigens and of the lymphatic endothelium marker podoplanin. In portal infiltrates, cells with electron microscopical and cell marker features of dendritic cells and expressing the activation markers CD54, CD80, CD83 and CD86 were organized in a discontinuous network, that embedded CD8+ lymphocytes in close contact with dendritic cells and came in contact with hepatocytes, sometimes infiltrating beyond the limiting plate. Also, dendritic cells were found within newly formed lymphatic capillaries in thin, infiltrated septa among hepatocytes.

CONCLUSIONS

This evidence strongly suggests a critical role of dendritic cells and newly formed lymphatics in the pathogenesis and organization of the immune infiltrate that characterizes HCV-related chronic active hepatitis.

OBJECTIVE

Recent reports demonstrated that osteoblast-like cells can also exert activities directly associated with the immune system (cytokine synthesis, antigen presentation, phagocytosis and stimulation of T lymphocytes). The present study aimed to analyze the effect of Transforming growth factorbeta1 (TGFbeta1), Fibroblast growth factor basic (FGFb), Platelet-derived growth factor-BB (PDGF-BB), Interleukin-1beta (IL-1beta), Interleukin-2 (IL-2), Lipopolysaccharide (LPS) and Interferon-gamma (IFNgamma) on the expression on osteoblast-like cells of antigens involved in antigen presentation.

METHODS

Flow cytometry was used to investigate whether the growth factors FGFb, TGFbeta1, PDGF-BB, IL-2, IL-1beta, LPS and IFNgamma modulate the expression on cultured human osteoblast-like cells of different antigens involved in antigen-presentation and T cell activation.

RESULTS

TGFbeta1 treatment significantly reduced the expression of CD54 and CD86. IL-1beta treatment significantly enhanced the expression of CD54, CD86 and HLA-DR. LPS and IFNgamma treatments produced a major increase in CD54, CD80, CD86 and HLA-DR expression. Expression of these antigen-presenting molecules was not significantly modified by FGFb, PDGF-BB or IL-2 treatment.

The distribution of intercellular adhesion molecule-1 (ICAM-1), a ligand for lymphocyte function antigen-1, on hematopoietic tissue was determined using the anti-ICAM-1 monoclonal antibody CL203.4 with flow cytometry and short-term semi-solid hematopoietic progenitor cultures. After timed incubation in media with fetal bovine serum, 29% of erythroid burst-forming units (BFU-E), 24% of erythroid colony-forming units (CFU-E), and 52% of granulocyte-macrophage colony-forming units (CFU-GM) bone marrow progenitors expressed ICAM-1. This finding, which is consistent with the detection of ICAM-1 on acute non-lymphoblastic leukemic blasts, is at variance with recent reports. ICAM-1 was also detected on bone marrow blasts, proerythroblasts, promyelocytes, and cells of monocyte/macrophage lineage, but was not detected on erythroblasts, normoblasts, neutrophilic myelocytes, metamyelocytes, bands, or on most lymphocytes. These results indicate that maturation of cells of the erythroid and myeloid lineage is associated with loss of ICAM-1. The distribution of ICAM-1 on bone marrow progenitors, early precursor cells, and accessory cells in conjunction with the function of this molecule in cell-cell interactions suggests that ICAM-1 may play a role in the cell-cell and cell-stromal interactions that regulate hematopoiesis.

Autologous chondrocyte implantation (ACI) is a method of cartilage repair. To improve the quality of regenerated tissue by ACI, it is essential to identify surface marker expression correlated with the differentiation status of monolayer expanded human articular chondrocytes and to define the index for discriminating dedifferentiated cells from monolayer expanded human articular chondrocytes. Normal human articular chondrocytes were cultured in monolayer until passage 4. At each passage, mRNA expression of collagen type I, II, and X and aggrecan was analyzed by real-time quantitative PCR, and the surface marker expression of CD14, CD26, CD44, CD49a, CD49c, CD54, and CD151 was analyzed by fluorescence-activated cell sorting (FACS). The ratios of mRNA levels of collagen type II to I (Col II/Col I) represented the differentiation status of chondrocytes more appropriately during monolayer culture. The surface marker expression of CD44, CD49c, and CD151 was upregulated according to the dedifferentiation status, whereas that of CD14, CD49a, and CD54 was downregulated. The most appropriate combination of the ratio of Col II/Col I was CD54 and CD44. Cell sorting was performed using a magnetic cell sorting system (MACS) according to CD54 and CD44, and real-time quantitative PCR was performed for the cell subpopulations before and after cell sorting. The expression of collagen type II and aggrecan of the chondrocytes after MACS was higher than that before sorting, but not significantly. The mean fluorescence intensity (MFI) ratio of CD54 to CD44 could be an adequate candidate as the index of the differentiation status.

To clarify the activation of peripheral blood T cells in Kawasaki disease (KD) patients, we investigated whether expression of lymphocyte function-associated antigen-1 (LFA-1, CD11a/CD18) and/or intercellular adhesion molecule-1 (ICAM-1, CD54) on peripheral blood T cells increases during the acute stage. Expression of cellular adhesion molecules was measured using flow cytometry. There was a decrease in the percentage of CD3+ T cells in the bright LFA-1 alpha and LFA-1 beta population and a concomitant increase in the dim population of LFA-1 alpha and LFA-1 beta during the acute stage, in comparison with those of the convalescent stage. In addition, we observed no significant differences in ICAM-1 expression during the acute stage compared with that of the convalescent stage. In our view the present data, in conjunction with previous reports on T-cell function during acute KD, suggest that activated T cells are temporarily withdrawn from peripheral circulation during acute KD.

It has been known that dendritic cells (DCs) including Langerhans cells (LCs) play a critical role in the skin sensitization process. Many attempts have been made to develop in vitro sensitization tests that employ DCs derived from peripheral blood mononuclear cells (PBMC-DC) or CD34+ hematopoietic progenitor cells (CD34+ HPC) purified from cord blood or bone marrow. However, the use of the DCs in in vitro methods has been difficult due to the nature of these cells such as low levels in the source and/or donor-to-donor variability. In our studies, we employed the human monocytic leukemia cell line, THP-1, in order to avoid some of these difficulties. At the start, we examined whether treatment of the cells with various cytokines could produce DCs from THP-1. Treatment of THP-1 cells with cytokines such as GM-CSF, IL-4, TNF-alpha, and/or PMA did induce some phenotypic changes in THP-1 cells that were characteristic of DCs. Subsequently, responses to a known sensitizer, dinitrochlorobenzene (DNCB), and a non-sensitizer, dimethyl sulfoxide (DMSO) or sodium lauryl sulfate (SLS), on the expression of co-stimulatory molecules, CD54 and CD86, were examined between the naive cells and the cytokine-treated cells. Interestingly, the naive THP-1 cells responded only to DNCB and the response to the sensitizer was more distinct than cytokine-treated THP-1 cells. Similar phenomena were also observed in the human myeloid leukemia cell line, KG-1. Furthermore, with treatment of DNCB, naive THP-1 cells showed augmented expression of HLA, CD80 and secretion of IL-1 beta. The response of THP-1 cells to a sensitizer was similar to that of LCs/DCs. Upon demonstrating the differentiation of monocyte cells in our system, we then evaluated a series of chemicals, including known sensitizers and non-sensitizers, for their potential to augment CD54 and CD86 expression on naive THP-1 cells. Indeed, known sensitizers such as PPD and 2-MBT significantly augmented CD54 and CD86 expression in a dose-dependent manner while non-sensitizers, such as SLS and methyl salicylate (MS), did not. To note, the metal allergens such as (NH(4))(2)[PtCl(4)], NiSO(4) and CoSO(4) augmented significantly only CD54 expression. Taking advantage of a cultured cell line, measurement of the co-stimulatory molecules, CD54 and CD86, on naive THP-1 cells following chemical exposure shows promise for the development of a simple, short-term in vitro sensitization test.

The effects of high-linear energy transfer (LET) radiation on immune function have not been clearly established. The major goal of this study was to evaluate leukocyte responses after whole-body exposure to high-LET radiation. C57BL/6 mice were exposed to 0, 0.5, 2 and 3 Gy (56)Fe(26+) particles (1055 MeV/nucleon, 148.2 keV/microm) and killed humanely 4 days after exposure. Spontaneous synthesis of DNA in blood and spleen cells was increased significantly in groups receiving either 2 or 3 Gy (P < 0.001). In contrast, a significant depression in the response of T lymphocytes to phytohemagglutinin (PHA) and concanavalin A (ConA) was noted (P < 0.005); the response to lipopolysaccharide (LPS), a B-cell mitogen, was similar among groups. A cytometric bead array assay revealed that the level of tumor necrosis factor alpha (Tnfa) secreted by splenocytes increased significantly with increasing (56)Fe-particle dose (P < 0.05); interferon gamma, interleukin2 (Il2), Il4 and Il5 were unaffected. Flow cytometry analysis showed that 2 and 3 Gy markedly reduced splenic mononuclear cells expressing the activation markers CD25 and CD71, both with and without the T-cell marker CD3 (P < 0.05); proportions also varied significantly. Similar patterns were noted in mononuclear and granular cells with adhesion markers CD11b and, to a lesser extent, CD54 (P < 0.05). The results show that a single, acute exposure to high-LET radiation induced changes that can profoundly alter leukocyte functions. The implications of the data are discussed in relation to low-LET radiation, altered gravity, and space flight.

Dendritic cells (DC) within tissues may acquire and process antigens, carry them into lymph nodes and cluster and activate T cells. The ability of DC to acquire antigen and to migrate to lymph nodes was estimated during murine retroviral infection caused by Rauscher leukaemia virus (RLV). A novel mechanism of inducing immunodeficiency has now been identified. In mice infected with RLV, DC failed to migrate into lymph nodes following exposure of the skin to the contact sensitizer, fluorescein isothiocyanate. RLV infection of a proportion of DC both in skin and lymph nodes, shown by semi-quantitative polymerase chain reaction (PCR) and down-regulation of expression of adhesion molecules (CD54 and CD44) on the surface of Langerhans' cells, may contribute to the described phenomenon. A failure of DC migration could be an important immunosuppressive mechanism of RLV infection in mice and we speculate on a similar role for DC in human immunodeficiency virus-1 (HIV-1) infection in humans.

The immunophenotypic characteristics of both bone marrow (BM) and peripheral blood (PB) mast cells (MC), from a patient suffering from an aggressive systemic mast cell disease (SMCD), were sequentially analyzed by flow cytometry using direct immunofluorescence. Analysis was carried out at diagnosis, during clinical response induced by interferon alfa-2h/prednisone therapy, and later at relapse. Our results show that together with the CD117 and IgE characteristic markers, at diagnosis BM MC showed strong expression of CD11c, CD13, CD29, CD33, CD44, CD45, CD63, and CD71, and they were also positive for CD2, CD22, CD25, and CD54 although at a lower level. PB MC displayed similar immunophenotypic characteristics although they had a lower expression of CD11c, CD25, CD33, CD63, CD69, and CD71 with a higher reactivity for CD117. Unlike BM MC, PB MC were weakly positive for CD41a and CD61. Sequential studies showed decreased numbers of both BM and PB MC during clinical response associated with a higher expression of the CD29 and CD54 adhesion molecules. In turn, clinical relapse was related to increased numbers of PB and BM MC together with lower CD2, CD11c, CD45, and and CD54 expression and a higher reactivity for the CD117 and CD25 antigens. CD2 had become negative at the last follow-up study. In addition, an increased proportion of S-phase MC was observed at relapse. These findings suggest that the assessment of the quantitative expression of cell-adhesion molecules and growth-factor receptors together with cell cycle studies of mast cells could be of value for monitoring therapy and predicting clinical outcome in aggressive SMCD.

BACKGROUND

For years Plasmodium vivax has been considered the cause of benign malaria. Nevertheless, it has been observed that this parasite can produce a severe disease comparable to Plasmodium falciparum. It has been suggested that some physiopathogenic processes might be shared by these two species, such as cytoadherence. Recently, it has been demonstrated that P. vivax-infected erythrocytes (Pv-iEs) have the capacity to adhere to endothelial cells, in which intercellular adhesion molecule-1 (ICAM-1) seems to be involved in this process.

METHODS

Adherence capacity of 21 Colombian isolates, from patients with P. vivax mono-infection to a microvascular line of human lung endothelium (HMVEC-L) was assessed in static conditions and binding was evaluated at basal levels or in tumor necrosis factor (TNF) stimulated cells. The adherence specificity for the ICAM-1 receptor was determined through inhibition with an anti-CD54 monoclonal antibody.

RESULTS

The majority of P. vivax isolates, 13 out of 21 (61.9%), adhered to the HMVEC-L cells, but P. vivax adherence was at least seven times lower when compared to the four P. falciparum isolates. Moreover, HMVEC-L stimulation with TNF led to an increase of 1.6-fold in P. vivax cytoadhesion, similar to P. falciparum isolates (1.8-fold) at comparable conditions. Also, blockage of ICAM-1 receptor with specific antibodies showed a significant 50% adherence reduction.

CONCLUSIONS

Plasmodium vivax isolates found in Colombia are also capable of adhering specifically in vitro to lung endothelial cells, via ICAM-1 cell receptor, both at basal state and after cell stimulation with TNF. Collectively, these findings reinforce the concept of cytoadherence for P. vivax, but here, to a different endothelial cell line and using geographical distinct isolates, thus contributing to understanding P. vivax biology.

Bradykinin (BK), a vasoactive, proinflammatory nonapeptide, promotes cell adhesion molecule (CAM) expression, leukocyte sequestration, inter-endothelial gap formation, and protein extravasation in postcapillary venules. These effects are mediated by bradykinin-1 (B1R) and-2 (B2R) receptors. We delineated some of the mechanisms by which BK could influence chronic inflammation by altering CAM expression on leukocytes, endothelium, and synovium in joint sections of peptidoglycan-polysaccharide-injected Lewis rats. Blocking B1R results in significantly increased joint inflammation. Immunohistochemistry of the B1R antagonist group revealed increased leukocyte and synovial CD11b and CD54 expression and increased CD11b and CD44 endothelial expression. B2R antagonism decreased leukocyte and synovial CD44 and CD54 and endothelial CD11b expression. Although these findings implicate B2R involvement in the acute phase of inflammation by facilitating leukocyte activation (CD11b), homing (CD44), and transmigration (CD54). Treatment with a B2R antagonist did not affect the disease evolution in this model. In contrast, when both BK receptors are blocked, the aggravation of inflammation by B1R blockade is neutralized and there is no difference from the disease-untreated model. Our findings suggest that B1R and B2R signaling show physiologic antagonism. B1R signaling suggests involvement in down-regulation of leukocyte activation, transmigration, and homing. Further studies are needed to evaluate the B1 receptor agonist's role in this model.

Type I interferons (IFN) have an essential role in antiviral defense, and they are produced upon viral infection in a variety of cells. IFN-alpha/beta treatment of immature dendritic cells (DC) is known to induce their phenotypic and functional maturation, but it remains unclear whether stimulation by this cytokine family influences the functions and maturation of Langerhans cells (LC). We used highly enriched (>95%) LC directly isolated from BALB/c mouse skin and addressed this issue, comparing LC with splenic CD11c(+) DC. Type I IFN-treated LC exhibited impaired ability to produce IL-12 and inflammatory cytokines, IL-6 and TNF-alpha, whereas IL-10 production was not augmented. In splenic DC, the production of inflammatory cytokines was rather enhanced by type I IFN treatment. With regard to chemokines, in both LC and splenic DC, type I IFN upregulated the production of inflammatory chemokines, such as CXCL10, CXCL11, CCL3, CCL4, and CCL5. Strikingly, IFN-beta treatment reduced the expression of CD40, CD54, CD80, and CD86 on LC, whereas IFN-beta-treated splenic DC showed enhanced expression of these molecules. Furthermore, IFN-beta-treated LC had impaired costimulatory activity for anti-CD3-induced proliferation of T cells. Finally, treatment with IFN-alpha/beta reduced the migratory capacity of LC to CCL21. These results indicate that type I IFN inhibit maturation and activation of LC in a direct manner. Our observations may provide a novel explanation for the reported inability of LC to act as potent antigen-presenting cells in cutaneous and mucosal viral infection.

OBJECTIVE

The aim of this study was to investigate whether adhesion molecules play a role in acute ischemic stroke.

METHODS

Using immunofluorescence phenotyping and flow cytometry, the expression of leukocyte adhesion molecules CD54, CD11a, CD11b and CD18 in peripheral blood were measured within 12 h after onset of ischemia in 20 patients with stroke. Follow-up measurements were performed at 7 and 30 days after ictus.

RESULTS

CD18 immunofluorescence was significantly increased on the leukocytes within 12 h after onset in patients with stroke compared with the age-matched control group (20 patients with other neurological diseases). Follow-up measurement of CD18 revealed normal results as found in the control group.

CONCLUSIONS

Our data support the idea that adhesion molecules are involved in tissue injury in ischemic stroke.

OBJECTIVE

The functional role of the leukocytes in the decidual is not clear. They may regulate the maternal immune response to the fetal allograft. However, the factors controlling maternal and fetal communication have not yet been identified.

METHODS

A comparative analysis of the phenotypes of decidual and peripheral blood large granular lymphocytes (LGLs) and T lymphocytes in early human pregnancy was performed on decidual tissue and blood samples obtained from ten patients at therapeutic abortion.

RESULTS

Whereas most of the decidual LGLs were found to have a CD56bright++ phenotype, most of the peripheral blood NK cells (90%) showed the classical CD56dim+ phenotype, and only a small proportion were CD56bright+ cells. Another striking difference was found in the expression of very late antigen 1 (VLA-1, CD49a): Almost all the decidual CD56bright++ LGLs, but virtually none of the peripheral blood CD56+ NK cells expressed this antigen. Further differences were found in the expression of CD16, CD44, CD45RA, CD54, and CD57. There were also differences in phenotype between T cells derived from decidual tissue and those derived from peripheral blood. Approximately 31% of the CD3+ decidual T cells expressed VLA-1, but this antigen was virtually absent on peripheral blood T cells. A further difference was seen in the expression of HLA-DR. This activation antigen was found on 32 +/- 13% of the decidual T cells but only 8 +/- 5% of the peripheral blood T cells. Additionally, the proportion of cells expressing CD38 was higher among decidual than peripheral blood T cells.

CONCLUSIONS

The findings suggest that both decidual LGLs and a subset of decidual T cells are activated and possibly play a role in the control of trophoblast growth and placental development.