Effect of Interleukin-8 and Monocyte Chemotactic Protein-1 on Adhesion of Circulating Granulocytes and Monocytes from Asthma Patients to Human Venous Endothelial Cells

The adhesive interactions between phagocytes and endothelial cells (EC) can be modulated by inflammatory cytokines and chemotactic proteins which are released during an inflammatory response. The aim of the present study was to investigate first whether the adhesive properties of granulocytes and monocytes from asthma patients for vascular endothelial cells differ from those of phagocytes from healthy individuals. Furthermore, we studied whether the chemokines interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) can affect the binding of phagocytes to EC. No differences were observed in binding of phagocytes from asymptomatic or symptomatic asthma patients and from healthy individuals to non-stimulated or cytokine-stimulated EC. Incubation of granulocytes with IL-8 did not influence their adhesion to non-stimulated EC but inhibited the adhesion of granulocytes to IL-1-stimulated EC. Incubation of monocytes with MCP-1 did not affect their adhesion to non-stimulated or cytokine-stimulated EC. Our results indicate that adhesion of phagocytes to EC depends on the activation state of the endothelial cells but not on the origin of the phagocytes, since there were no differences in the adhesion of phagocytes from asthma patients and healthy individuals to non-stimulated or cytokine-stimulated EC.     

Adhesion molecule expression and response to chemotactic agents of human monocyte-derived macrophages

Human monocyte-derived macrophages have been proposed as agents of anti-tumour immunotherapy. The aim of the present study was to investigate in vitro the properties of these cells likely to control their recruitment to the sites of inflammation and tumours. The expression of adhesion molecules involved in the binding of monocytes to endothelial cells was modified during monocyte-macrophage differentiation, with a significant increase in CD11c, CD14 and intercellular adhesion molecule-1 (ICAM-1). Monocyte-derived macrophages were sensitive to chemoattractants, in particular to the monocyte-specific chemokine monocyte chemotactic protein-1 (MCP-1). They responded by an increased expression of adhesion molecules and were attracted by the cytokine in an under-agarose migration assay. The migration response, however, decreased after days 4–5 of monocyte differentiation into macrophage. In conclusion, human monocyte-derived macrophages show alterations of surface structures involved in the recognition of inflammatory endothelium. This may explain why the cells are poorly recruited to the sites of inflammation and tumours when introduced into the circulation.     

Expression of adhesion molecules on mononuclear cells from individuals with stable atopic asthma

Activated mononuclear cells (lymphocytes and monocytes) (MNCs) circulate in peripheral blood and accumulate in the airways of individuals with steady-state asthma. The expression of adhesion molecules on MNCs of 10 patients with steady-state atopic asthma and 10 non-atopic control subjects was measured by flow cytometry. The mean fluorescence intensity of CD23 (P= 0.0003), CDl la (P= 0.034), and very late antigen-4 (VLA-4) (P= 0.016) was increased on lymphocytes of asthmatic patients relative to those of controls. Although the expression of CD16 (P= 0.002) and CD23 (P= 0.002). which are associated with differentiation into macrophages, was increased on monocytes of patients relative to those of controls, monocyte expression of VLA-4 (P= 0.006) and sialyl Lewis X (P= 0.005) was reduced. The concentration of interleukin-4 (lL-4) in serum was significantly higher in asthmatic patients than in normal subjects (P= 0.023), and a significant correlation was apparent between the serum concentration of lL-4 and the expression of VLA-4 on lymphocytes (p= 0.71, P= 0.03) or on monocytes (p=?0.72, P= 0.03) in asthmatic patients. Results suggest that lL-4 may contribute to the priming of adhesion molecule expression on lymphocytes even in steady-state conditions in individuals with chronic allergic inflammation.     

Respiratory syncytial virus infection increases regulated on activation normal T cell expressed and secreted and monocyte chemotactic protein 1 levels in serum of patients with asthma and in human monocyte cultures

BackgroundRespiratory syncytial virus (RSV) infection is associated to episodic exacerbations of asthma involving alveolar macrophages and chemokine production.ObjectiveThe aim of this study was to determine the circulating levels of monocyte chemotactic protein 1 (MCP-1), regulated on activation normal T cell expressed and secreted (RANTES), and substance P (SP) in patients with and without asthma with acute respiratory RSV infection and the chemokine profile in RSV- infected monocyte cultures from normal individuals and individuals with asthma.MethodsIn this regard, 31 adult patients with acute respiratory infection (15 patients with asthma) were studied. MCP-1, RANTES and SP were measured in serum and in supernatants from monocyte cultures by enzyme-linked immunosorbent assay (ELISA).ResultsIncreased levels of MCP-1 and RANTES were observed in serum from patients with asthma related to RSV infection. RSV-infected monocyte cultures from healthy individuals showed increased content of those chemokines, and monocyte cultures from patients with asthma showed increased expression of MCP-1.ConclusionThese data show that RSV infection induces increased circulating level of chemokines in patients with asthma, and this finding could be mediated in part by the interaction virus-monocyte.     

Differential immobilization and hierarchical involvement of chemokines in monocyte arrest and transmigration on inflamed endothelium in shear flow

Monocyte extravasation into areas of inflammation involves sequential interactions of multiple adhesion molecules. However, differential contribution of chemokines produced by cytokine-stimulated endothelium and their receptors to leukocyte attachment and transmigration under flow conditions remains to be elucidated. The activation of endothelial cells with TNF-alpha up-regulated mRNA and protein expression of the CXC chemokine GRO-alpha and the CC chemokine monocyte chemotactic protein (MCP)-1, which act through the receptors CXCR2 and CCR2 expressed on monocytes, respectively. Whereas GRO-alpha was immobilized to endothelial cells via heparan sulfate proteoglycans, MCP-1 was secreted in a soluble form. Consequently, inhibition experiments with blocking peptide analogues and monoclonal antibodies revealed that GRO-alpha and its receptor CXCR2 but not MCP-1 and its receptors substantially contributed to conversion of rolling into firm, shear-resistant arrest of monocytes to TNF-alpha-stimulated endothelium in physiological flow. In contrast, MCP-1 and CCR2 but not GRO-alpha and CXCR2 mediated spreading, shape change and subsequent transendothelial migration, which was evident in flow but rarely in stasis and may thus require the establishment of a diffusible MCP-1 gradient. Differential patterns of presentation may determine a functional specialization and hierarchy of chemokines and their receptors in sequential steps of monocyte emigration on inflamed endothelium and shear flow.     

Acute psychological stress and exercise and changes in peripheral leukocyte adhesion molecule expression and density

OBJECTIVE: This study examined the effects of acute psychological stress and exhaustive exercise on the expression and density of adhesion molecules (L-selectin, lymphocyte function antigen-1 [LFA-1], and intracellular adhesion molecule-1 [ICAM-1]) on monocytes, granulocytes, and lymphocytes. METHODS: Forty-five healthy volunteers performed a 15-minute public speaking task and a 15- to 18-minute bicycle ergometer challenge. RESULTS: In general, both the exercise and speaking tasks led to increases in the number of circulating leukocytes and lymphocyte subsets. The density of L-selectin (CD62L) on mixed lymphocytes and T lymphocytes was decreased in response to exercise (p values < .001). Both stressors led to an increased density of LFA-1 (CD11a) on mixed lymphocytes (p values < .01), whereas CD11a density on monocytes and granulocytes remained unchanged. ICAM-1 (CD54) density was unaffected, but the number of lymphocytes, monocytes, and granulocytes expressing CD54 increased in the circulation on both stressors. CONCLUSIONS: The data indicate that both psychological stress and exercise have significant effects on cellular expression of adhesion molecules on circulating leukocytes. Given the crucial role that adhesion molecules on circulating cells play in inflammation and disease, these findings may have clinical relevance in sympathetic nervous system-induced immune activation.     

Infection of human endothelial cells with Staphylococcus aureus induces the production of monocyte chemotactic protein-1 (MCP-1) and monocyte chemotaxis.

Bacterial infection coincides with migration of leucocytes from the circulation into the bacterium-infected tissue. Recently, we have shown that endothelial cells, upon binding and ingestion of Staphylococcus aureus, exhibit proinflammatory properties including procoagulant activity and increased intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression on the cell surface, resulting in hyperadhesiveness, mainly for monocytes. The enhanced extravasation of monocytes to bacterium-infected sites is facilitated by the local production of chemotactic factors. From another study we concluded that the locally produced chemokine MCP-1 is important in the recruitment of monocytes to the peritoneal cavity in a model of bacterial peritonitis. In the present study we investigated whether cultured human endothelial cells after infection with bacteria produce and release MCP-1, which in turn stimulates monocyte chemotaxis. We observed that endothelial cells released significant amounts of MCP-1 within 48 h after ingestion of S. aureus. This was dependent on the number and the virulence of the bacteria used to infect the endothelial cells. The kinetics as well as the amount of MCP-1 released by S. aureus-infected endothelial cells differed markedly from that released by endothelial cells upon stimulation with IL-1beta. Supernatant from S. aureus-infected or IL-1beta-stimulated cells promoted monocyte chemotaxis which was almost entirely abrogated in the presence of neutralizing anti-MCP-1 antibody, indicating that most of the chemotactic activity was due to the release of MCP-1 into the supernatant. Our findings support the notion that endothelial cells can actively initiate and sustain an inflammatory response after an encounter with pathogenic microorganisms, without the intervention of macrophage-derived proinflammatory cytokines.     

Om-85 bv upregulates the expression of adhesion molecules on phagocytes through a cd14-independent pathway

OM-85 BV is a preparation of bacterial extracts which proved to be of some efficacy in the prevention of respiratory tract infections. However, the mechanisms of action of this drug remain unclear. As we recently observed that OM-85 BV upregulates the expression of adhesion molecules on phagocytes, we took advantage of this property to determine whether the activating effects of OM-85 BV on monocytes and granulocytes depend on its interaction with CD14 molecules. Indeed, CD14 represents the major cell surface receptor for lipopolysaccharide and other bacterial products at the surface of leucocytes. First, we found that the upregulation of Mac-1 (CD11b/CD18) induced in vitro by OM-85 BV on monocytes was not blocked by an anti-CD 14 monoclonal antibody (mAb) which inhibits monocyte responses to lipopolysaccharide. Similarly, the anti-CD14 mAb inhibited upregulation of Mac-1 on granulocytes when it was induced by lipopolysaccharide but not by OM-85 BV. To confirm that the effects of OM-85 on the expression of Mac-1 is CD14-independent, we analysed the responses of a patient with paroxysmal nocturnal haemoglobinuria, a disease associated with a defect of CD14 expression at the membrane of phagocytes. We found that monocytes and granulocytes of this patient displayed an impairment in Mac-1 upregulation in response to lipopolysaccharide whereas they responded normally to OM-85 BV. We conclude that OM-85 BV activates phagocytes through a CD14-independent pathway. The characterisation of the cell surface receptors of monocytes and granulocytes involved in the interactions with OM-85 BV might provide a molecular clue to the mode of action of this preparation of bacterial extracts.     

Exercise-induced changes in the expression of surface adhesion molecules on circulating granulocytes and lymphocytes subpopulations

This study examined the relationship between exercise-induced changes in the concentration of circulating immunocompetent cells and their surface expression of adhesion molecules: L-selectin (CD62L) and three ₂-integrins [LFA-1(CD11a/CD18), Mac-1 (CD11b/CD18), and p150/95(CD11c/CD18)]. Eight young male volunteers exercised on a cycle ergometer for 60 min at 60% maximal oxygen uptake. Peripheral blood samples, collected every 30 min throughout exercise and during the 2-h recovery period, were used for flow-cytometric analysis. The experimental results were compared with control data obtained ever 60 min at corresponding times of the nonexercise day. The exercise regimen induced a granulocytosis and a lymphocytosis, mainly due to an elevation of CD8⁺ and CD16⁺ cells. During recovery, a further granulocytosis occurred but accompanied by a lymphopenia. The increased CD8⁺ cell-count during exercise was characterized by a selective mobilization of the CD62L^– and CD11a^high cells, i.e.primed CD8⁺ cells. A postexercise suppression of CD4⁺ cell-count was derived only from CD62L⁺ cells. The CD11b⁺ and CD11c⁺ lymphocytes also increased during exercise, largely attributable to an increase in CD16⁺ cells which co-expressed CD11b and CD11c molecules. The CD62L surface density of granulocytes increased significantly during recovery. This resulted from a selective influx of CD62L^high granulocytes into the circulation. There were no significant changes in per-cell density of the three ₂-integrins on granulocytes and lymphocytes throughout the experimental period. These results suggest that the cell-surface expression of CD62L (and CD I la) molecules is associated with the differential mobilization of CD8⁺ cells during exercise, the postexercise suppression of CD4^– cell-counts and the granulocytosis following exercise.     

Oral corticosteroids decrease eosinophil and CC chemokine expression but increase neutrophil, IL-8, and IFN-gamma-inducible protein 10 expression in asthmatic airway mucosa

BACKGROUND: Cytokines and chemokines have been implicated in the pathogenesis of asthma. Inhaled corticosteroids have been shown to decrease the number of eosinophils and to downregulate T H 2 cytokines but to increase neutrophils. The effect of corticosteroids on chemokine expression in asthma has not yet been investigated. OBJECTIVE: We sought to investigate the effect of a 2-week course of oral corticosteroid (methylprednisolone, 40 mg/d) on the expression of CXC chemokines (IL-8 and IFN-gamma-inducible protein 10 [IP-10]) and CC chemokines (eotaxin and monocyte chemotactic proteins [MCPs] 1-4) in endoscopic biopsy specimens of 13 patients with moderate-to-severe asthma. METHODS: CD3, major basic protein, and elastase immunoreactivities were monitored before and after treatment by using immunocytochemistry. Eotaxin, IL-8, IP-10, MCP-1, MCP-2, MCP-3, and MCP-4 mRNA expression in epithelium and submucosa were studied by using in situ hybridization. RESULTS: Corticosteroids reduced the number of CD3-positive T cells and major basic protein-positive eosinophils ( P < .05), whereas the number of neutrophils were increased ( P < .05). Corticosteroids also reduced the number of eotaxin ( P < .05), MCP-3, and MCP-4 mRNA-positive cells ( P < .001) in the epithelium and subepithelium. However, corticosteroids caused a significant increase in the epithelial expression of IL-8 ( P < .001), IP-10 ( P < .05), and MCP-2 mRNAs ( P < .01). Corticosteroids had no effects on MCP-1 mRNA expression. CONCLUSION: Our results demonstrate the dual nature of corticosteroids. Although corticosteroids can downregulate the expression of some asthma-associated chemokines, such as eotaxin, MCP-3, and MCP-4, they can also upregulate the expression of other chemokines, including IL-8, IP-10, and MCP-2. The failure of oral corticosteroids to inhibit IL-8 mRNA expression might contribute to persistent airway neutrophilia observed in patients with moderate-to-severe asthma, despite treatment with corticosteroids.     

Evaluation of Signal Transduction Pathways in Chemoattractant-Induced Human Monocyte Chemotaxis

The intracellular signaling pathways involved in human monocyte chemotaxis toward a variety of chemoattractant molecules were evaluated using selected pharmacological agents. Neither phosphatidylinositol-3-kinase (PI3K) or extracellular signal-regulated kinase (ERK) activity were required for monocyte migration toward monocyte chemoattractant protein-1 (MCP-1), RANTES (Regulated on Activation, Normal T cell Expressed and Secreted), macrophage inflammatory protein-1 (MIP-1) or formyl-Met-Leu-Phe (fMLP), since pretreatment with wortmannin or LY294002, or with PD098059, had no effect on the chemotactic response. Addition of forskolin and IBMX significantly attenuated chemotaxis to each of these chemoattractants and was reversed by co-treatment with Rp-cAMP, a competitive inhibitor of cAMP-dependent protein kinase A. Incubation with the protein kinase C (PKC) inhibitor GF109203X-HCl (GF109) did not affect monocyte migration, but pretreatment of monocytes with PMA significantly impaired the response to each of these chemotactic agents. Inhibition by PMA was reversed by co-treatment with GF109, implying that heterologous PKC activation is capable of desensitizing chemokine and fMLP-induced monocyte chemotaxis. These results help to define the signalling pathways involved in human monocyte chemotaxis and suggest pharmacological approaches to evaluating the cross-desensitization of chemoattractant-induced leukocyte migration.     

Reduced monocyte adhesion to aortae of diabetic plasminogen activator inhibitor-1 knockout mice

Objective and design

To determine the requirement of plasminogen activator inhibitor-1-knockout (PAI-1) for monocyte adhesion in animals and cells under diabetic conditions.

Methods and subjects

Monocyte adhesion assay, enzyme-linked immunosorbent assay, and Western blotting were used in analyzing samples from PAI-1-knockout (PAI-1-KO) mice or cultured human umbilical vein endothelial cells (HUVEC).

Treatments

Diabetes in PAI-1-KO and wild-type mice was induced by intraperitoneal injection of streptozotocin (STZ). HUVEC was transfected with short interference RNA (siRNA) against PAI-1, tumor necrosis factor-α (TNFα), or toll-like receptor (TLR4), and then was treated with glycated low-density lipoproteins (glyLDL).

Results

The adhesion of monocytes to aortic intima was reduced in PAI-1-KO mice, which was associated with decreased levels of TNFα and monocyte chemotactic protein-1 (MCP-1) in plasma and cardiovascular tissue, and increased abundances of urokinase plasminogen activator (uPA) and uPA receptor (uPAR) in cardiovascular tissue compared to wild-type mice. Significant reductions in monocyte adhesion, inflammatory, and fibrinolytic regulators were detected in cardiovascular tissue or plasma in diabetic PAI-1-KO mice compared to wild-type diabetic mice. Transfection of PAI-1, TNFα or TLR4 siRNA to HUVEC inhibited glyLDL-induced monocyte adhesion to EC. PAI-1 siRNA inhibited the abundances of TLR4 and TNFα in EC.

Conclusion

The findings suggest that PAI-1 is required for diabetes-induced monocyte adhesion via interactions with uPA/uPAR, and it also regulates TLR4 and TNFα expression in vascular EC. Inhibition of PAI-1 potentially reduces vascular inflammation under diabetic condition.

     

Monocyte and Neutrophil Adhesion to Matrix Proteins is Selectively Enhanced in the Presence of Inflammatory Mediators

The authors investigated the time course of monocyte and neutrophil adhesion to fibronectin, vitronectin and albumin precoated culture wells, using mixed leucocyte populations from healthy blood donors. Moreover, the influence of chemotactic agonists on the adhesion properties as well as the quantitative expression of CD29, CD11b/CD18 and CD61 was analysed by flow cytometry. Different chemotactic agonists were used representing a classical chemotactic agonist (fMLP), and agonists with a preferential effect on monocytes (RANTES) and neutrophils (IL-8), respectively. The authors found a gradual increase in monocyte and neutrophil adhesion to all three surfaces, reaching a plateau at 15 min of incubation. Adhesion to fibronectin was significantly higher at all time points (5, 15 and 60 min, respectively) compared with vitronectin and albumin in both monocytes and neutrophils. Neutrophil adhesion to vitronectin was significantly lower at 60 min compared with 15 min. Monocyte adhesion to albumin was increased by fMLP and RANTES and to vitronectin also by IL-8. Neutrophil adhesion to albumin and vitronectin was increased by fMLP and IL-8, but not RANTES. The adhesion to fibronectin was not altered by any of the chemotactic agonists used. The quantitative levels of CD11b/CD18, but not CD29 and CD61, was increased by fMLP, but not RANTES nor IL-8. The authors conclude that the adhesion of human monocytes and neutrophils to vitronectin and albumin, but not fibronectin, is selectively enhanced by chemotactic agonists and may contribute to the selective accumulation of different leucocyte subsets at the inflammatory site.     

Chemokines and soluble adhesion molecules in renal transplant recipients with cytomegalovirus infection

Cytomegalovirus (CMV) infection is associated with leucocyte infiltration in various organs, which supports a role for chemokines and adhesion molecules in the pathogenesis of CMV infection. In a prospectively conducted study of renal transplant recipients, 10 patients with CMV disease, five patients with asymptomatic CMV infection and 10 patients who did not have any CMV infection were included. During CMV infection, and in particular during CMV disease, plasma levels of the chemokines IL-8, macrophage inflammatory protein-1alpha (MIP-1alpha) and monocyte chemotactic protein-1 (MCP-1) and the soluble adhesion molecules vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1) and L-selectin increased and were positively correlated with the degree of CMV pp65 antigenaemia. Furthermore, a decrease in plasma levels of these chemokines and adhesion molecules was observed following ganciclovir therapy in the patients with CMV disease. This could suggest a role for these molecules in the pathogenesis of CMV infection.     

Expression of IFN-gamma-inducible protein; monocyte chemotactic proteins 1, 3, and 4; and eotaxin in TH1- and TH2-mediated lung diseases

BACKGROUND: Chemokines are involved in the influx of leukocytes into the airways in inflammatory lung diseases. The differential cell recruitment characteristic of T(H)1 versus T(H)2 immune responses may be associated with differential chemokine expression. OBJECTIVE: We investigated the expression of chemokines; monocyte chemotactic proteins (MCPs) 1, 3, and 4; eotaxin; and IFN-gamma-inducible protein 10 (IP-10) in both T(H)1- and T(H)2-mediated lung diseases. METHODS: By using immunocytochemistry and in situ hybridization, we examined the protein and mRNA expression, respectively, in bronchoalveolar lavage and biopsy samples in subjects with asthma, tuberculosis, sarcoidosis, and chronic bronchitis. RESULTS: Increased immunoreactivity and mRNA expression of IP-10 and of the MCPs was found in the bronchoalveolar lavage fluid and biopsy specimens of subjects with asthma and tuberculosis compared with that of control subjects (P <.005). IP-10, however, was particularly increased in subjects with sarcoidosis (P <.001). Eotaxin, on the other hand, was increased only in patients with asthma when compared with control subjects (P <.005). CONCLUSION: This study demonstrates that MCP-1, MCP-3, and MCP-4 expression is not specifically associated with lung diseases characterized by a particular cytokine profile. In contrast, IP-10 is mostly expressed in T(H)1-mediated diseases, and eotaxin expression seems to be specifically associated with lung diseases of a T(H)2 cytokine profile.     

Interleukin-7-dependent nonclassical monocytes and CD40 expression are affected in children with type 1 diabetes

The important role of IL-7 in the generation of self-reactive T-cells in autoimmune diseases is well established. Recent studies on autoimmunity-associated genetic polymorphisms indicated that differential IL-7 receptor (IL-7R) expression of monocytes may play a role in the underlying pathogenesis. The relevance of IL-7-mediated monocyte functions in type 1 diabetes remains elusive. In the present study, we characterized monocyte phenotype and IL-7-mediated effects in children with type 1 diabetes and healthy controls with multicolor flow cytometry and t-distributed Stochastic Neighbor-Embedded (t-SNE)-analyses. IL-7R expression of monocytes rapidly increased in vitro and was boosted through LPS. In the presence of IL-7, we detected lower monocyte IL-7R expression in type 1 diabetes patients as compared to healthy controls. This difference was most evident for the subset of nonclassical monocytes, which increased after IL-7 stimulation. t-SNE analyses revealed IL-7-dependent differences in monocyte subset distribution and expression of activation and maturation markers (i.e., HLA-DR, CD80, CD86, CD40). Notably, monocyte CD40 expression increased considerably by IL-7 and CD40/IL-7R co-expression differed between patients and controls. This study shows the unique effects of IL-7 on monocyte phenotype and functions. Lower IL-7R expression on IL-7-induced CD40_high monocytes and impaired IL-7 response characterize monocytes from patients with type 1 diabetes.     

Actinobacillus actinomycetemcomitans serotype b-specific polysaccharide antigen stimulates production of chemotactic factors and inflammatory cytokines by human monocytes.

Serotype b-specific polysaccharide antigen (SPA) was extracted from whole cells of Actinobacillus actinomycetemcomitans Y4 by autoclaving and purified by chromatography on DEAE-Sephadex A-25 and Sephacryl S-300. SPA induced the release of monocyte and leukocyte chemotactic factors by human monocytes. Polymyxin B had almost no effect on the release of monocyte chemotactic factor, but a monoclonal antibody against SPA markedly inhibited it. Human monocytes stimulated with SPA exhibited the increased mRNA expression of monocyte chemoattractant protein 1 (MCP-1) and a neutrophil chemotactic factor, interleukin-8 (IL-8). On the other hand, SPA induced the release of IL-1, IL-6, and tumor necrosis factor (TNF) and enhanced the expression of IL-1alpha, IL-1beta, IL-6, and TNF alpha (TNF-alpha) mRNAs. Human monocytes expressed MCP-1 and IL-8 mRNAs when stimulated by human recombinant IL-1alpha, I1-1beta, IL-6, and TNF-alpha, suggesting that these inflammatory cytokines induced by SPA might participate in the production of chemotactic factors in human monocytes.     

Upregulation of adhesion molecules induced by broncho-vaxom on phagocytic cells.

Whole blood was incubated with the bacterial extract Broncho-Vaxom (OM85) at various concentrations and for different periods of time. Expression of the beta 2-integrins (LFA-1, CD11a/CD18; MAC-1, CD11b/CD18; p150,95, CD11c/CD18) and ICAM-1 (CD54) by monocytes and granulocytes was studied using flow cytometry. OM85 enhanced the expression of MAC-1 and ICAM-1 on monocytes and granulocytes in a dose-dependent manner. Maximal expression was achieved with 1 mg/ml bacterial extract. The effect on MAC-1 expression was not due to the low concentration of endotoxin contaminating the preparation (less than 1 ng/mg) since polymyxin-B did not substantially affect the adhesion molecule upregulation induced by OM85. In addition, OM85 enhanced the expression of p150,95 on monocytes and granulocytes, and also increased expression of LFA-1 on monocytes, but not on granulocytes. While MAC-1 and p150,95 expression reached peak values between 1 and 6 h, levels of ICAM-1 rose constantly for 10 h. We suggest that the clinical interest of OM85 in the management of recurrent infections could be related to be upregulation of adhesion molecules induced by this bacterial extract.     

Increased adhesion to vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 of eosinophils from patients with asthma

Adhesion of peripheral blood eosinophil and neutrophil granulocytes to the endothelial cell adherence receptors E-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 has been measured. The study included patients with allergic rhinitis, patients with mild allergic and nonallergic asthma, and healthy individuals; 10 persons were in each group. In addition, assay of eosinophil and neutrophil cell surface expression of the receptor complex CD11b/CD18 was performed. Increased eosinophil adhesion to vascular cell adhesion molecule-1 (p < 0.05) and intercellular adhesion molecule-1 (p < 0.05) was demonstrated in the patients with a more labile asthma, that is, a peak expiratory flow rate variability of more than 10%, suggesting a relationship to the degree of ongoing inflammation in the airways of the patients. The increased eosinophil adhesion was most probably due to a functional upregulation of the CD11b/CD18 and very late activation antigen-4 receptors, because the number of receptors measured as cell surface expression was unaltered. The increased eosinophil adhesion in the patients with high peak expiratory flow rate variability appeared independent of atopy. The increased adhesion was not entirely specific to the eosinophils, because neutrophils from patients with a peak expiratory flow rate variability of more than 10% also demonstrated increased adhesion to intercellular adhesion molecule-1 (p < 0.05) when compared with neutrophils from the patients with low peak expiratory flow rate variability. In conclusion, the demonstrated priming of eosinophil adhesion to vascular cell adhesion molecule-1 and intercellular adhesion molecule-1 might be one contributing mechanism behind the selective accumulation of eosinophils in the lung tissue of patients with asthma. (J ALLERGY CLIN IMMUNOL 1995;96:941-50.)     

Monocyte and Neutrophil Adhesion to Matrix Proteins is Selectively Enhanced in the Presence of Inflammatory Mediators

The authors investigated the time course of monocyte and neutrophil adhesion to fibronectin, vitronectin and albumin precoated culture wells, using mixed leucocyte populations from healthy blood donors. Moreover, the influence of chemotactic agonists on the adhesion properties as well as the quantitative expression of CD29, CD11b/CD18 and CD61 was analysed by flow cytometry. Different chemotactic agonists were used representing a classical chemotactic agonist (fMLP), and agonists with a preferential effect on monocytes (RANTES) and neutrophils (IL-8), respectively. The authors found a gradual increase in monocyte and neutrophil adhesion to all three surfaces, reaching a plateau at 15 min of incubation. Adhesion to fibronectin was significantly higher at all time points (5, 15 and 60 min, respectively) compared with vitronectin and albumin in both monocytes and neutrophils. Neutrophil adhesion to vitronectin was significantly lower at 60 min compared with 15 min. Monocyte adhesion to albumin was increased by fMLP and RANTES and to vitronectin also by IL-8. Neutrophil adhesion to albumin and vitronectin was increased by fMLP and IL-8, but not RANTES. The adhesion to fibronectin was not altered by any of the chemotactic agonists used. The quantitative levels of CD11b/CD18, but not CD29 and CD61, was increased by fMLP, but not RANTES nor IL-8. The authors conclude that the adhesion of human monocytes and neutrophils to vitronectin and albumin, but not fibronectin, is selectively enhanced by chemotactic agonists and may contribute to the selective accumulation of different leucocyte subsets at the inflammatory site.