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Monocyte Function (monocyte + function)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Identification of a 55 kDa Haemonchus contortus excretory/secretory glycoprotein as a neutrophil inhibitory factor

PARASITE IMMUNOLOGY, Issue 1 2008
K. A. ANBU
SUMMARY Haemonchus contortus is an economically important gastric parasite infecting sheep and goats. The parasite survives the host immune attack by releasing protective molecules. In the present study, a 55 kDa secretory glycoprotein (gp55) was identified that inhibited host neutrophils as judged by reduced H2O2 production by these cells. The binding of gp55 to neutrophils was confirmed by flow cytometry. This binding was mediated by cellular CD11b/CD18 integrin. The glycoprotein gp55 also bound to goat monocytes and lymphocytes and inhibited monocyte function. Using light fluorescence microscopy, gp55 was localized at the surface of adult worms. The absence of gp55 in the infective L3 larvae and its expression in the blood-feeding stage support a role for gp55 in the parasitic stage of the organism. [source]

Functional immaturity of cord blood monocytes as detected by impaired response to hepatocyte growth factor

PEDIATRICS INTERNATIONAL, Issue 4 2001
Qi Jiang
AbstractBackground: Monocytes as antigen-presenting cells play an important role in host defense and transplantation. However, there are little reports on cord blood monocytes, and the role of monocytes in cord blood transplantation is largely unknown. Methods and Results: There are several cytokines affecting monocyte function. These include interferon-,, interleukin-4, interleukin-10, granulocyte macrophage-colony stimulating factor and hepatocyte growth factor (HGF). We investigated the effect of these cytokines on antigen-presenting capacity (APC) of cord and adult blood monocytes. Using either mononuclear cells or purified CD4+ T cells as responder cells, HGF enhanced APC of adult monocytes most effectively among these cytokines. In contrast, cord blood monocytes failed to respond to HGF. As HLA, costimulatory and adhesion molecules may affect APC function, we examined these antigens of monocytes following HGF stimulation. The HGF upregulated integrin ,5 subunit (CD49e) and intercellular adhesion molecule-1 (CD54) was expressed in adult blood monocytes, but not in cord blood. In kinetic studies, HGF downregulated c-met protein/HGF receptor expression of adult monocytes in lower concentrations and at shorter incubation time as compared with that of cord blood. Conclusions: The results suggest that impaired response of cord blood monocytes to HGF may be responsible, in large part, for their functional immaturity. [source]

The 423Q polymorphism of the X-linked inhibitor of apoptosis gene influences monocyte function and is associated with periodic fever

ARTHRITIS & RHEUMATISM, Issue 11 2009
Massimo Ferretti
Objective Hereditary periodic fever syndromes (HPFs) develop as a result of uncontrolled activation of the inflammatory response, with a substantial contribution from interleukin-1, or tumor necrosis factor , (TNF,). The HPFs include familial Mediterranean fever (FMF), hyperimmunoglobulinemia D with periodic fever syndrome (HIDS), TNF receptor,associated syndrome (TRAPS), and cryopyrinopathies, which are attributable to mutations of the MEFV, MVK, TNFRSF1A, and CIAS1 genes, respectively. However, in many patients, the mutated gene has not been determined; therefore, the condition in these patients with an HPF-like clinical picture is referred to as idiopathic periodic fever (IPF). The aim of this study was to assess involvement of X-linked inhibitor of apoptosis (XIAP), which plays a role in caspase inhibition and NF-,B signaling, both of which are processes that influence the development of inflammatory cells. Methods The XIAP gene (X-linked) was sequenced in 87 patients with IPF, 46 patients with HPF (13 with HIDS, 17 with TRAPS, and 16 with FMF), and 182 healthy control subjects. The expression of different alleles was evaluated by sequencing XIAP -specific complementary DNA mini-libraries and by real-time polymerase chain reaction and Western blot analyses. The functional effect of XIAP on caspase 9 activity was assessed by a fluorimetric assay, and cytokine secretion was evaluated by enzyme-linked immunosorbent assay. Results Sequencing disclosed a 1268A>C variation that caused a Q423P amino acid substitution. The frequency of 423Q-homozygous female patients and 423Q-hemizygous male patients was significantly higher in the IPF group than in the control group (69% versus 51%; odds ratio 2.17, 95% confidence interval 1.23,3.87, P = 0.007), whereas no significant difference was detected in the HPF group (59%) compared with controls. In primary lymphocytes and transfected cell lines, 423Q, as compared with 423P, was associated with higher XIAP protein and messenger RNA expression and lower caspase 9 activation. In lipopolysaccharide-activated monocytes, 423Q was associated with higher secretion of TNF,. Conclusion These results suggest that 423Q is a predisposing factor for IPF development, possibly through its influence on monocyte function. [source]

An anti-inflammatory oligopeptide produced by Entamoeba histolytica down-regulates the expression of pro-inflammatory chemokines

PARASITE IMMUNOLOGY, Issue 10 2003
Dolores Utrera-Barillas
SUMMARY Axenically grown Entamoeba histolytica produces a pentapeptide (Met-Gln-Cys-Asn-Ser) with anti-inflammatory properties that, among others, inhibits the in vitro and in vivo locomotion of human monocytes, sparing polymorphonuclear leucocytes from this effect [hence the name originally given: Monocyte Locomotion Inhibitory Factor (MLIF)]. A synthetic construct of this peptide displays the same effects as the native material. We now added MLIF to resting and PMA-stimulated cells of a human monocyte cell line and measured the effect upon mRNA and protein expression of pro-inflammatory chemokines (RANTES, IP-10, MIP-1,, MIP-1,, MCP-1, IL-8, I-309 and lymphotactin) and the shared CC receptor repertoire. The constitutive expression of these chemokines and the CC receptors was unaffected, whereas induced expression of MIP-1,, MIP-1,, and I-309, and that of the CCR1 receptor , all involved in monocyte chemotaxis , was significantly inhibited by MLIF. This suggests that the inhibition of monocyte functions by MLIF may not only be exerted directly on these cells, but also , and perhaps foremost , through a conglomerate down-regulation of endogenous pro-inflammatory chemokines. [source]