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Leucocyte Functions (leucocyte + function)
Selected AbstractsIn vitro interactions between Neoparamoeba spp. and salmonid leucocytes; the effect of parasite sonicate on anterior kidney leucocyte functionJOURNAL OF FISH BIOLOGY, Issue 2006K. Gross Sonicated Neoparamoeba spp. (Nspp) did not affect the in vitro respiratory burst response of leucocytes isolated from Atlantic salmon Salmo salar, rainbow trout Oncorhynchus mykiss and chinook salmon Oncorhynchus tshawytscha anterior kidneys (P > 0·05). Atlantic salmon and chinook salmon leucocytes pre-incubated with the parasites, however, responded to phorbol myristate acetate (PMA) stimulation with a greater response compared to cells incubated with PMA on its own (P < 0·05). Sonicated Nspp was not chemo-attractive for anterior kidney leucocytes isolated from all three fish species. [source] Retinol binding protein isolated from acute renal failure patients inhibits polymorphonuclear leucocyte functionsEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 11 2004G. Cohen Abstract Background, Protein factors accumulating in sera of patients with end-stage renal disease (ESRD) that interfere with the nonspecific immune response by inhibiting essential functions of polymorphonuclear leucocytes (PMNLs) have previously been described. No such factor has been isolated from acute renal failure (ARF) patients to date. Materials and methods, Using a three-step chromatographic procedure involving ion exchange, size exclusion and hydrophobic interaction chromatography we purified the apo- and holo-form of retinol binding protein (RBP) from high-flux dialyser (polyacrylonitrile; AN69) ultrafiltrates of patients with ARF. Their effect on the chemotaxis of PMNLs isolated from healthy donors was determined by the under-agarose method. Whole-blood assays applying flow cytometry were used to assess phagocytosis and the oxidative metabolism of PMNLs. Apoptosis was assessed by determining the DNA content using propidium iodide. Results, Isolated apo- and holo-forms of RBP were truncated on their C-terminus as determined by mass spectrometry. All isolates significantly inhibited the chemotactic movement of PMNLs obtained from healthy donors and the PMNL oxidative metabolism stimulated by E. coli. These effects were concentration dependent. Retinol binding protein had no influence on the PMNL oxidative metabolism stimulated by PMA and on PMNL phagocytosis. Commercially available RBP isolated from urine influenced PMNL functions in the same way. Inhibition of p38 mitogen-activated protein kinase (MAPK) by SB203580 significantly attenuated the phagocytosis-induced respiratory burst and RBP did not lead to a further decrease. Polymorphonuclear leucocyte apoptosis was significantly inhibited by RBP. Conclusions, The apo- and holo-forms of RBP isolated from the ultrafiltrate of ARF patients inhibit PMNL chemotaxis, oxidative metabolism and apoptosis. Therefore, RBP may be considered a uraemic toxin contributing to a disturbed immune defence. [source] Down-regulation of CXCR1 and CXCR2 expression on human neutrophils upon activation of whole blood by S. aureus is mediated by TNF-,CLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2001I. Tikhonov It was suggested that bacterial products can inhibit the expression of leucocyte chemokine receptors during sepsis and affect leucocyte functions in septic syndrome. Superantigens and toxins produced by Staphylococcus aureus are capable of activating leucocytes via binding to MHC-II antigens on monocytes and T-cell receptor molecules on T lymphocytes. It was recently shown that staphylococcal enterotoxins directly down-regulate the expression of CC chemokine receptors on monocytes through binding to MHC class II molecules. We studied the effects of killed S. aureus on the expression of interleukin-8 receptors, CXCR1 and CXCR2, on polymorphonuclear leucocytes (PMN), which are known to lack the expression of MHC-II antigens. It was shown that S. aureus down-regulated the cell-surface expression of CXCR1 and CXCR2 on PMN in the whole blood and total blood leucocyte fraction containing PMN and monocytes, but did not modulate IL-8 receptor expression in purified PMN suspension. Antibody to TNF-, abrogated down-regulation of IL-8 receptors induced by S. aureus. In contrast, LPS reduced CXCR1 and CXCR2 expression in purified PMN and whole blood in a TNF-,-independent manner. We further showed that TNF-,-induced decrease of CXCR1 and CXCR2 expression was associated with lower IL-8 binding and lower CXCR1 and CXCR2 mRNA levels, and was abrogated by protease inhibitors. We suggest that during septicemia, S. aureus may inhibit neutrophil responsiveness to IL-8 and other CXC chemokines via TNF-,- mediated down-regulation of CXCR1 and CXCR2. [source] Identification of wild type and variants of oestrogen receptors in polymorphonuclear and mononuclear leucocytesCLINICAL ENDOCRINOLOGY, Issue 1 2006Denis Stygar Summary Objective, ,Leucocytes play an important role in the pathogenesis of autoimmune and cardiovascular diseases. Clinical and epidemiological observations indicate that the sex steroid hormones, particularly oestrogens, may regulate leucocyte functions. The assumption that oestrogens have a direct effect on leucocytes has to be supported by identification of functional oestrogen receptors (ER) in leucocytes. This study aimed at investigating the presence of ER subtypes in different types of leucocytes isolated from peripheral blood of female and male donors. Design and patients, ,A total of nine men (age range 18,43 years) and nine women (age range 19,42 years) all healthy blood donors, were recruited for the study. The donors did not receive any medication or hormonal contraceptives for the last three months. Ten millilitres of peripheral blood was collected from each donor. Polymorphonuclear leucocytes (PMN) and peripheral blood mononuclear cells (PBMC) were purified by density gradient centrifugation. Measurements, ,ER, and ER, mRNA expression was measured by real-time reverse transcriptase,polymerase chain reaction (RT-PCR), and ER proteins were analysed by Western blot in the PBMC and PMN leucocyte populations. In addition, expression profiles of ER variant isoforms were characterized by conventional PCR using the splice-targeted primer approach. Results, ,Although we detected wild-type ER, and ER, mRNAs in PBMC but not in PMN cells, the ER, and ER, proteins were found in both cell types using Western blot. We observed that both ER, and ER, proteins differ in size between PMN and PBMC, suggesting that the two leucocyte populations contain diverse variant isoforms of ER, and ER,. RT-PCR analysis of exon-deleted ER splice variants revealed that PBMC express several exon-deleted variants of ER, and ER,, along with wild-type receptor, whereas the PMN cells only express exon-deleted variant isoforms and no wild-type ER, or ER,. Conclusions, ,Our study demonstrates the presence of ER, and ER, in PBMC and PMN cells from female and male donors. The ER, and ER, genes have complex transcriptional profiles, with many receptor variant isoforms being expressed. Considering the diversity of ER isoforms in leucocyte subtypes, we conclude that the expected effect of oestrogen would be highly cell type-specific. Further studies are needed to test the functional activity of ER isoforms and their relation to disease. [source] | ||||||||||