Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Integrin alphaXbeta2”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1996

Immuno-inflammatory responses in the tissue adjacent to titanium miniplates used in the treatment of mandibular fractures.

The immuno-inflammatory responses to titanium miniplates used in the treatment of mandibular fractures were studied immunohistochemically at light and electron microscope levels. Titanium miniplates were stably situated on the cortical bone surface. In the soft tissue adjacent to the surface of titanium miniplates, double layered connective tissue was observed, which consisted of dense fibrous connective tissue, and relatively loos connective tissue contained proliferated blood vessels with hypertrophied endothelial cells. These vascular endothelial cells expressed HLA-DR, CD54 and CD62P antigens. In some cases they were CD62Epositive. CD68+ and CD11c+ round or spindle-shaped macrophages had infiltrated around the small vessels. Fine titanium particles were observed in the cytoplasm of these macrophages. Both CD4+ and CD8+ T lymphocytes had also infiltrated around venules in some cases. They were CD4+ T lymphocyte-dominant. Immunoelectron microscopically, CD68+ and CD11c+ macrophages contained titanium particles in the lysosomes. Most of the macrophages showed varying degrees of degenerative change. The presence of titanium was confirmed by energy-dispersive X-ray analysis.

Adolescent↗
PubMed2000

The interaction between anticoagulant protein S and complement regulatory C4b-binding protein (C4BP).

An important mechanism of regulation of blood coagulation is the anticoagulant protein C pathway. In this pathway, the anticoagulant activity of activated protein C is increased by its cofactor protein S. The cofactor activity of protein S can be regulated by binding to complement regulatory C4b-binding protein (C4BP). The sites of interaction of protein S and C4BP are discussed.

Animals↗
PubMed2000

Increased expression of inflammatory cytokines and adhesion molecules by alveolar macrophages of human lung allograft recipients with acute rejection: decline with resolution of rejection.

BACKGROUND: Alveolar macrophages (AM) are the major population in bronchoalveolar lavage (BAL) cells; we assessed their role in human lung allograft recipients by correlating the expression of adhesion molecules and inflammatory cytokines with clinical outcome of allograft. METHODS: We obtained BAL samples from patients and enriched them for AM in plastic petri dish for 2 hours at 37 degrees C in 5% CO(2). Expression of intercellular adhesion molecule-1 (ICAM-1, CD54), platelet endothelial cell adhesion molecule-1 (PECAM-1, CD31), and CD11c was assessed by flow cytometry using monoclonal antibodies. We assessed cytokine profile using Multi-Probe RNase protection assay. RESULTS: Alveolar macrophages that express CD11c, CD31 and CD54 were increased in patients with either rejection or infection compared with those without rejection and infection. The difference in the percentage of AM expressing CD11c and CD31 between the rejection group and patients without rejection and infection group was statistically significant (CD11c, p < 0.01; CD31, p < 0.03). Interleukin (IL)-1 alpha, IL-1 beta, IL-1 receptor antagonist (IL-1Ra), and IL-6 expression was higher in the rejection group than in patients without rejection. Five out of 9 patients in the rejection group expressed high levels of IL-15 and tumor necrosis factor-alpha compared with patients without rejection and infection. The increased number of AM expressing adhesion molecules and elevated expression of cytokines observed during acute rejection declined to basal levels after successful treatment and resolution of rejection. This study demonstrates that lung allograft rejection is associated with increased expression of adhesion molecules and inflammatory cytokines by AM, which could facilitate mononuclear cell adhesion and extravasation contributing to the allograft injury in lung transplant recipients.

Bronchoalveolar Lavage Fluid↗
PubMed2001

IL-25 induces IL-4, IL-5, and IL-13 and Th2-associated pathologies in vivo.

We have characterized a cytokine produced by Th2 cells, designated as IL-25. Infusion of mice with IL-25 induced IL-4, IL-5, and IL-13 gene expression. The induction of these cytokines resulted in Th2-like responses marked by increased serum IgE, IgG(1), and IgA levels, blood eosinophilia, and pathological changes in the lungs and digestive tract that included eosinophilic infiltrates, increased mucus production, and epithelial cell hyperplasia/hypertrophy. In addition, our studies show that IL-25 induces Th2-type cytokine production by accessory cells that are MHC class II(high), CD11c(dull), and lineage(-). These results suggest that IL-25, derived from Th2 T cells, is capable of amplifying allergic type inflammatory responses by its actions on other cell types.

Amino Acid Sequence↗
PubMed2002

A restricted subset of dendritic cells captures airborne antigens and remains able to activate specific T cells long after antigen exposure.

Mice sensitized for a Th2 response to Leishmania LACK antigen developed allergic airway inflammation upon exposure to LACK aerosol. Using multimers of I-A(d) molecules bound to a LACK peptide as probes, we tracked the migration of LACK-specific Th2 cells to the airways. Elevated numbers of LACK-specific Th2 cells remained in the airways for 5 weeks after the last aerosol. Substantial numbers of DC presenting LACK peptides were found in the airways, but not in other compartments, for up to 8 weeks after antigen exposure. These LACK-presenting airway DC expressed CD11c and CD11b as well as high levels of surface molecules involved in uptake and costimulation. Taken together, our results may explain the chronic Th2 airway inflammation characteristic of allergic asthma.

Administration, Inhalation↗
PubMed2002

CR3 (CD11b/CD18) and CR4 (CD11c/CD18) are involved in complement-independent antibody-mediated phagocytosis of Cryptococcus neoformans.

IgM and IgA to the Cryptococcus neoformans capsular glucuronoxylomannan (GXM) promote complement-independent phagocytosis by macrophages with efficiency comparable to that of IgG1. IgM- and IgA-mediated phagocytosis of C. neoformans was proportional to CR3 expression, inhibited by Abs to CR3 (CD11b/CD18) and CR4 (CD11c/CD18), and dramatically reduced with macrophages of CD18-deficient mice. IgM and IgA promoted ingestion of yeast cells by CHO cells expressing CR3 and CR4. In contrast, IgG1-mediated phagocytosis was only partially inhibited by Abs to CR3 and CR4. Phagocytosis by IgM and IgA but not IgG1 was inhibited by soluble GXM, which binds CD18. Involvement of CR in antibody-mediated complement-independent phagocytosis indicates a new link between innate and adaptive immune systems.

Animals↗
PubMed2002

In vivo depletion of CD11c+ dendritic cells abrogates priming of CD8+ T cells by exogenous cell-associated antigens.

Cytotoxic T lymphocytes (CTL) respond to antigenic peptides presented on MHC class I molecules. On most cells, these peptides are exclusively of endogenous, cytosolic origin. Bone marrow-derived antigen-presenting cells, however, harbor a unique pathway for MHC I presentation of exogenous antigens. This mechanism permits cross-presentation of pathogen-infected cells and the priming of CTL responses against intracellular microbial infections. Here, we report a novel diphtheria toxin-based system that allows the inducible, short-term ablation of dendritic cells (DC) in vivo. We show that in vivo DC are required to cross-prime CTL precursors. Our results thus define a unique in vivo role of DC, i.e., the sensitization of the immune system for cell-associated antigens. DC-depleted mice fail to mount CTL responses to infection with the intracellular bacterium Listeria monocytogenes and the rodent malaria parasite Plasmodium yoelii.

Animals↗
PubMed2001

Class II-targeted antigen is superior to CD40-targeted antigen at stimulating humoral responses in vivo.

We examined the efficacy of using monoclonal antibodies to target antigen (avidin) to different surface molecules expressed on antigen presenting cells (APC). In particular, we targeted CD40 to test whether the "adjuvant" properties of CD40 signaling combined with targeted antigen would result in enhanced serologic responses. We targeted avidin to class II as a positive control and to CD11c as a negative control. These surface proteins represent an ensemble of surface molecules that signal upon ligation and that are expressed on professional APC, in particular dendritic cells (DC). We observed that targeting class II molecules on APC was superior to targeting CD40, or CD11c. However, CD40 and CD11c could function as targets for antigen bound monoclonal antibodies under certain conditions. Interestingly, inclusion of anti-CD40 mAb with the targeting anti-class II-targeted antigens negatively affects humoral response, suggesting that CD40 signaling under certain conditions may suppress processing and/or presentation of targeted antigen.

Animals↗
PubMed2002

The clearance of apoptotic cells: implications for autoimmunity.

Apoptosis has been clearly characterised by the ability to limit the activation of inflammatory responses through the disposal of the apoptotic cell by rapid uptake by phagocytes. The exposure of phosphatidylserine deriving from the loss of plasma lipid asymmetry is the early membrane signal which alerts the phagocyte about the imminent apoptotic death of the cell. Also modifications of membrane carbohydrate groups on apoptotic cells contribute to phagocyte recognition. Soluble proteins such as C1q, mannose-binding lectin, surfactant proteins A and D, C-reactive protein, C3bi, beta2-glycoprotein I and growth arrest specific gene-6 bind to apoptotic cells and act as "opsonins" thus favouring their clearance. A redundant and promiscuous system of receptors including integrins, scavenger receptors, CR3 and CR4, calreticulin, CD14 and Mer receptor ensures an efficient and rapid uptake of apoptotic cells. In animal models and in human pathology, single genetic defects of molecules involved in apoptotic cell clearance seem to be the main determinant in the development of autoimmunity. The uptake of apoptotic cells by phagocytes provides an immunomodulatory effect in that it triggers the release of anti-inflammatory cytokines, inhibits the production of inflammatory cytokines and leads to T cell tolerance. Impaired clearance of apoptotic cells or the presence of 'danger' signals may modify the balance between tolerance induction and activation of T cells leading to an effective autoimmune response.

Animals↗
PubMed1998

Induction of immunity to Schistosoma mansoni: interaction of schistosomula with accessory leucocytes in murine skin and draining lymph nodes.

A single exposure to radiation-attenuated cercariae of Schistosoma mansoni induces a high level of protective immunity in C57BL/6 mice, which is mediated by Th1 responses. Events in the skin and/or draining lymph nodes early after exposure are crucial for the induction of protection, and we have investigated the interactions of vaccinating parasites with host leucocytes in these 2 locations. We observed extensive lateral spreading of cercarial secretions along layers of the stratum corneum but not between keratinocytes. There was little direct contact with host leucocytes during the first 1-2 days when the parasites lay at the base of the epidermis, but cells accumulated in the underlying dermis. In contrast to normal parasites, attenuated larvae persisted in the dermis for > 10 days, often surrounded by aggregates of macrophages/dendritic cells. Whilst cells bearing MHC II, CD11b or CD11c markers were present in the lymph nodes, particularly in the periphery and paracortical areas, no obvious redistribution was seen as a result of parasite residence there for 5-15 days. However, ultrastructural observations revealed numerous cells with macrophage/dendritic morphology in the vicinity of parasites, in some instances closely adherent to the tegument. The observations strongly suggest that the tegument is a potent source of the antigens which prime the immune system in the lymph nodes of vaccinated mice for a protective response.

Animals↗
PubMed1992

Pentraxin family of proteins interact specifically with phosphorylcholine and/or phosphorylethanolamine.

Pentraxins are a family of serum proteins characterized by five identical subunits that are noncovalently linked. The two major types of pentraxins are C-reactive protein (CRP) and serum amyloid P component (SAP). CRP proteins are identified by their calcium-dependent interaction with phosphorylcholine. This study showed that SAP also bound to phosphorylated compounds but had a high specificity for phosphorylethanolamine. Thus, human CRP and SAP show high specificity that is complementary for the related compounds, phosphorylcholine and phosphorylethanolamine, respectively. This relationship suggests a complementary and/or related function for the pentraxins. Pentraxins from other species were also examined. Mouse SAP showed binding interactions and specificity similar to human SAP. Female protein (FP) from hamster and rat CRP showed a hybrid specificity and bound to both phosphorylethanolamine and phosphorylcholine. All of the proteins that bound phosphorylethanolamine also associated with human C4b-binding protein (C4BP). With the exception of human and rat CRP, all the proteins also bound to vesicles containing acidic phospholipids. All of these binding interactions were calcium-dependent and mutually exclusive, suggesting that they involved the same site on the protein. These findings suggest possible ways to examine the function of the pentraxins.

Alpha-Globulins↗
PubMed2002

Human umbilical vein endothelial cells express complement receptor 1 (CD35) and complement receptor 4 (CD11c/CD18) in vitro.

We have examined complement receptors on human umbilical vein endothelial cells (HUVEC) and found that they express complement receptor 1 (CR1, CD35) and complement receptor 4 (CR4, CD11c/CD18), but not complement receptor 3 (CR3, CD11b/CD18). Binding of monoclonal antibodies against CR1 (CD35) and CR4 (CD11c/CD18) to HUVEC was demonstrated by flow cytometry. The presence of the corresponding mRNAs was confirmed by reverse transcriptase-polymerase chain reaction (RT-PCR) and sequencing of the amplified cDNA fragments. When HUVEC were treated with inflammatory mediators, chemotactic agents or the secretagogue phorbol-12-myristate-13-acetate (PMA), no change in reactivity to CR1 (CD35) or CR4 (CD11c/CD18) monoclonal antibodies was detected on the surface of the cells compared with untreated cells. The presence of CR1 (CD35) and CR4 (CD1c/CD18) on HUVEC indicates that endothelial cells (EC) have the potential to bind C3b and iC3b, respectively, which both mediate biological effects in the course of complement activation.

Antibodies, Monoclonal↗
PubMed2002

Decline in the expression of C4 binding protein alpha-chain gene during ageing of the rat liver.

It appears that consistent changes in the levels of activity of a small cohort of genes (probably less than 1% of all active genes) occur in all mammalian cells during ageing. We have studied this phenomenon in rat liver using an optimised form of differential display. During this investigation we observed one gene which exhibited a decline in expression in livers from young adult (6 months) to aged adult (24 months) animals. The differential expression of this gene was confirmed by single strand conformational polymorphism (SSCP) gel analysis and Northern blotting. Densitometry of the latter indicated that there was a decline of 35% in its expression with age. Characterisation of the isolated PCR fragment demonstrated it to code for the alpha subchain of the complement 4 binding protein (C4BP). The C4BP is a key regulatory protein of the complement system and this observation therefore indicates that a decline in the efficiency of the complement system may be an important factor in the overall decline in immune function that has been observed during ageing.

Aging↗
PubMed2001

Structure and flexibility of the multiple domain proteins that regulate complement activation.

In this review we summarise more than 10 years of biophysical exploration into the structural biology of the regulators of complement activation (RCA). The five human proteins responsible for regulation of the early events of complement are homologous and are composed largely from building blocks called "complement control protein (CCP) modules". Unlike most multiple domain proteins they do not contain any of the other widely occurring module types. This apparent simplicity of RCA structure, however, is belied by their sophistication of function. In fact, the structures of the individual CCP modules exhibit wide variations on a common theme while the extent and nature of intermodular connections is diverse. Some neighbouring modules within a protein stabilise each other and some co-operate to form specific binding surfaces. The degree of true "modularity" of CCPs is open to debate. The study of RCA proteins clearly illustrates the value of combining complementary structural biology techniques. The results could have implications for folding, evolution, flexibility and structure-function relationships of other molecules in the large, diverse and little understood category of multiple domain proteins.

Amino Acid Motifs↗
PubMed2002

Characterization of a common precursor population for dendritic cells.

Dendritic cells (DCs) are essential for the establishment of immune responses against pathogens and tumour cells, and thus have great potential as tools for vaccination and cancer immunotherapy trials. Experimental evidence has led to a dual DC differentiation model, which involves the existence of both myeloid- and lymphoid-derived DCs. But this concept has been challenged by recent reports demonstrating that both CD8- and CD8+ DCs, considered in mice as archetypes of myeloid and lymphoid DCs respectively, can be generated from either lymphoid or myeloid progenitors. The issue of DC physiological derivation therefore remains an open question. Here we report the characterization of a DC-committed precursor population, which has the capacity to generate all the DC subpopulations present in mouse lymphoid organs---including CD8- and CD8+ DCs, as well as the B220+ DC subset---but which is devoid of myeloid or lymphoid differentiation potential. These data support an alternative model of DC development, in which there is an independent, common DC differentiation pathway.

Animals↗
PubMed1997

Infiltration of mononuclear inflammatory cells into primary colorectal carcinomas: an immunohistological analysis.

Local immunoregulation mediated by mononuclear tumour-infiltrating cells is considered of importance for tumour progression of colorectal cancer, although the balance between immunosuppressor and cytotoxic activities is unclear. Colorectal cancers from 26 patients were investigated using a panel of monoclonal antibodies in order to identify subsets of mononuclear inflammatory cells and to study their pattern of distribution in relation to tumour stage and cytotoxic immune reactivity against the tumour. In all but five tumours, mononuclear cells, lymphocytes or monocytes were present in fairly large numbers, particularly in the stroma. The infiltration of CD4+ mononuclear cells predominated over the CD8+ subset. Infiltration near the tumour cells was found in four cancers only. Stromal infiltration of CD11c+ macrophages was found in all but eight tumours. Small regressive areas, in which the histological architecture of the tumours was broken down, were found in 17 tumours with intense or moderate infiltration by CD4+ lymphocytes or CD11c+ macrophages. Probably this destruction of tumour tissue was caused by cytotoxic activity of the tumour-infiltrating mononuclear cells. In Dukes' class A and B tumours, CD4+ lymphocytes predominated over CD4+ cells with macrophage morphology, but the latter were increasingly found in Dukes' class C and D disease. The occurrence of MHC II-positive macrophages and lymphocytes in different Dukes' classes was similar to that of CD4+ cells. In contrast to this, CD11c+ and CD11a+ cells were more frequent in Dukes' A and B class tumours compared with Dukes' C and D. Four out of nine tumours of the latter stages showed a poor inflammatory reaction. The interpretation of our results is that the subsets of tumour-infiltrating mononuclear cells change with advancing Dukes' class and that the local immune control is gradually broken down in progressive tumour growth, even if some cytotoxic activity is still present.

Aged↗