• Journal of Veterinary Clinics
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• v.35 no.5
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• pp.195-199
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• 2018

Zinc is necessary for normal functions in the immune system. The objective of the study is to examine the effect of zinc on the chemotactic activity of porcine peripheral blood polymorphonuclear cells (PMNs). A modified Boyden chamber was used to determine the directional migration distance of PMNs. Various concentrations of zinc showed no chemotactic activity to PMNs. However, culture supernatant from peripheral blood mononuclear cells (PBMCs) treated with zinc remarkably increased the chemotactic activity of PMNs when compared with culture supernatant from PBMCs treated without zinc. Culture supernatant from PBMCs treated without zinc also increased the migration distance of PMNs relative to vehicle control (medium alone). Increasing effect in chemotactic activity of PMNs by culture supernatant from PBMCs treated with zinc was inhibited by treatment of porcine anti-interleukin (IL)-8 polyclonal antibody (pAb). This effect was not affected by heat treatment ($4-85^{\circ}C$). This corresponded with heat stable physical characteristics of IL-8. These results suggest that zinc can upregulate the chemotaxis of PMNs, which is primary mediated by IL-8 chemotactic factor released from PBMCs treated with zinc.

• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.37-41
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• 1999

The immunostimulating effects of egg white derivatives (EWD) on the phagocytic response of feline peripheral blood polymorphonuclear cells (PMN) as well as mono- nuclear cells (MNC) were examined. The phagocytic activity was analyzed by a flow cytometry system. The EWD showed directly an enhanced effect on the phagocytic response of MNC but not PMN. The phagocytic activity of MNC was enhanced by culture supernatant from MNC and PMN treated with EWD, respectively. Similarly, the phagocytic activity of PMN was enhanced by culture supernatant from MNC but not PMN treated with EWD. It was, therefore, indicated that the enhanced phagocytic activity of feline PMN could be mainly mediated by humoral factor(s) released from MNC treated with EWD. These results suggested that EWD could enhance the phagocytosis of feline peripheral blood phagocytes.

• Journal of Veterinary Clinics
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• v.37 no.2
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• pp.61-66
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• 2020

Nickel is a nutritionally essential trace element that plays an important role in the immune system of several animal species. The aim of this study was to examine the effect of nickel chloride on chemotactic activity of peripheral blood polymorphonuclear cells (PMNs) and whether this effect is associated with interleukin (IL)-8 and a nuclear factor-kappa B (NF-κB)-dependent pathway. Peripheral blood mononuclear cells (PBMCs) and PMNs were isolated by Percoll solution (Specific gravity; 1.080) and 1.5% dextran treatment, respectively. A modified Boyden chamber assay was used to measure the chemotactic activity of PMNs. The level of IL-8 in culture supernatant from PBMCs was measured by enzyme-linked immunosorbent assay (ELISA). Both of PBMCs and PMNs exhibited a low viability when cultured with concentration of greater than 1,000 μM of nickel chloride for 24 h. Thus, nickel chloride was used at concentration of 500 μM, which preserved cell viability. Treatment with nickel did not directly affect the chemotactic activity of PMNs. However, the chemotactic activity of PMNs was remarkably increased by culture supernatant from PBMCs treated with nickel chloride (500 μM) for 24 h. Recombinant porcine IL-8 polyclonal antibody (pAb) neutralized the enhancing effect on the chemotactic activity of PMNs by culture supernatant from PBMCs treated with nickel and this culture supernatant had higher IL-8 levels than the culture supernatant from untreated PBMCs. In addition, n-tosyll-phenylalanine chloromethyl ketone (TPCK), a NF-κB inhibitor, antagonized the enhancing effect on the chemotactic activity of PMNs by the culture supernatant from PBMCs treated with nickel. These results suggested that nickel stimulates porcine PBMCs to produce IL-8, which increases the chemotaxis of PMNs via NF-κB-dependent pathway.

• Journal of Veterinary Clinics
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• v.25 no.2
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• pp.73-78
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• 2008

Ketamine is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist and a short-acting general anaesthetic agent for human and veterinary use. We previously reported that treatment with ketamine impairs oxidative burst activity of canine peripheral blood leukocytes. In this study, the effect of ketamine on phagocytic capacity of canine peripheral blood leukocytes was examined in vitro. Phagocytic capacity was analyzed by using a flow cytometry. Ketamine directly decreased the phagocytic capacity of peripheral blood polymorphonuclear cells (PMN) and monocytes but not total peripheral blood mononuclear cells (PBMC). In addition, the phagocytic capacity of PMN and monocytes was inhibited by the ketamine-treated PBMC but not PMN culture supernatant. These results suggest that ketamine has a direct inhibitory effect on the phagocytic capacity of canine peripheral blood phagocytes and involves the production of soluble factor(s) from canine PBMC, which may suppress the phagocytic capacity.

• Journal of Veterinary Clinics
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• v.16 no.1
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• pp.31-36
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• 1999

The aim of this study is to determine the phagocytosis-promoting factor(s) for feline peripheral blood polymorphonuclear cells (PMN) by culture supernatant from mono-nuclear cells (MNC) treated with egg white derivatives (EWD). The phagocytic activity of PMN was analyzed by a flow cytometry system. The EWD did not show direct effect on the phagocytic response of PMN. The phagocytic activity of PMN was enhanced by culture supernatant from MNC but not PMN treated with EWD. Therefore, it was suggested that the enhanced phagocytic activity of feline PMN could be mediated by humoral factor(s) released from MNC treated with EWD. Thus, the phagocytosis-promoting factor(s) in supernatant fraction from MNC culture treated with EWD were isolated by reverse phase high pressure liquid chromatography. The resulting supernatant fraction on 29.02 minutes of retention time showed high phagocytic activity of PMN. The molecular weight of this supernatant fraction was 16 to 18 kDa when analyzed by capillary electrophoresis. The isoelectric point was pH 5.76 when assessed by ion-exchange chromatography. These results suggest that EWD stimulates feline MNC to elaborate a phagocytosis-promoting factor, 16 to 18 kDa of molecular weight, which could be an important mediator for the enhancement of phagocytic activity of feline peripheral blood phagocytes. Further study will be needed to elucidate this phagocytic factor.

• Journal of Veterinary Clinics
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• v.37 no.5
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• pp.249-254
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• 2020

Neutrophil extracellular trap (NET) formation is an immune response for the invasion of microbes. The purpose of this study is to examine the effect of zinc on NET formation of porcine peripheral blood polymorphonuclear cells (PMNs). The NET formation of PMNs was measured by fluorescence microplate reader. The production of tumor necrosis factor (TNF)-α in the culture supernatants from zinc-treated peripheral blood mononuclear cells (PBMCs) was measured by enzyme-linked immunosorbent assay (ELISA). Zinc itself did not have no effect on NET formation. However, the NET formation of PMNs was increased by culture supernatants from PBMCs treated with zinc. Also, the NET formation of PMNs was increased by recombinant porcine (rp) TNF-α. The production of TNF-α in PBMCs culture supernatants was shown to increase upon zinc treatments. These NET formations of PMNs increased by either culture supernatant from PBMCs treated with zinc or rpTNF-α were inhibited by treatment of anti-rpTNF-α polyclonal antibody (pAb). These results suggested that zinc has an immunostimulating effect on the NET formation of PMNs, which is mediated by TNF-α released from zinc-treated PBMCs. Therefore, zinc may play an important role for NET formation in the defense of porcine inflammatory diseases.

• Journal of Veterinary Clinics
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• v.23 no.4
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• pp.393-399
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• 2006

Ketamine, one of general anesthetics for human and veterinary use, is a non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist which interferes with the action of excitatory amino acids. It has been reported to impair various leukocyte functions. In this study, the effect of ketamine on the oxidative burst activity (OBA) of canine peripheral blood leukocytes was examined. The OBA of canine peripheral blood phagocytes was analyzed by flow cytometry system. Ketamine at higher concentration such as $1,000{\mu}M$ exhibited a low viability of leukocytes. Thus, ketamine was used at concentration of 10 to $500{\mu}M$ showing no cytotoxic effect and high cell viability. The OBA of leukocytes in the presence or absence of latex beads was analyzed by addition of dihydrorhodamine 123. The direct treatment of ketamine revealed the inhibitory effect on the OBA of peripheral blood polymorphonuclear cells (PMN) and monocyte-rich cells but not peripheral blood mononuclear cells (PBMC) in the presence of latex beads. However, when latex beads were not added to PMN, its OBA was not inhibited by ketamine. The OBA of PMN and monocyte-rich cells but not PBMC in the presence of latex beads was also inhibited by culture supernatant from ketamine-treated- PBMC but not -PMN. But the OBA of PMN in the absence of latex beads was not inhibited by culture supernatant from PBMC treated with ketamine. Therefore, these results suggested that ketamine has the inhibitory effect on the OBA of canine peripheral blood phagocytes such as neutrophils and monocytes during phagocytic response.

• Journal of Veterinary Clinics
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• v.21 no.1
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• pp.23-28
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• 2004

1,2-benzopyrone has been shown to affect on the activation and stimulation of macrophage. To examine the immunostimulating effect of 1,2-benzopyrone on the phagocytic response of canine peripheral blood mononuclear cells (PBMC) as well as polymorphonuclear cells (PMN), the phagocytic activity of phagocytes was analyzed by flow cytometry system using FITC-labelled latex. The 1,2-benzopyrone did not show any direct effect on phagocytic response of PBMC and PMN. But it showed an enhanced effect on the phagocytic response of monocyte-rich cells fractioned by cell size from dot plot profile in flowcytometric cytography of PBMC. The phagocytic activity of these cells was also enhanced by addition of culture supernatant from PBMC treated with 1,2-benzopyrone. Similarly, the phagocytic activity of PMN but not PBMC in the same procedures was enhanced by culture supernatant from PBMC treated with 1,2-benzopyrone. However, the culture supernatant from PMN treated with 1.2-benzopyrone did not show the enhancing effect on phagocytic activity for monocyte-rich cells and PMN. These results, therefore, suggested that enhanced phagocytic activity of canine peripheral blood PMN and monocytes may be mainly mediated by humoral factor(S) released from PBMC treated with 1,2-benzopyrone.

• Journal of Veterinary Clinics
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• v.21 no.3
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• pp.236-242
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• 2004

1,2-benzopyrone can stimulate macrophages to increase the ability of phagocytosis. Peripheral blood polymorphonuclear cells (PMN) and macrophages destroy microbial organisms with reactive oxygen species (ROS), called oxidative burst activity (OBA). This study was undertaken to determine whether 1,2-benzopyrone affects the OBA on the phagocytic response of canine peripheral blood phagocytes. The OBA of phagocytes in the addition or absence of latex beads was analyzed by flow cytometry system using dihydrorhodamine 123 (DHR). The direct treatments of 1,2-benzopyrone have no effect on the OBA of peripheral blood mononuclear cells (PBMC), PMN and monocyte-rich cells regardless of addition of latex beads. When latex beads are added to PMN, the OBA of PMN was remarkably enhanced by culture supernatant from PBMC but not PMN treated with 1,2-benzopyrone. Similary, it was also enhanced by human recombinant (hr) $TNF-\alpha.$ However, when latex beads were not added to PMN, its OBA was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. The OBA of latex beads-phagocytized PBMC and monocyte-rich cells was not enhanced by culture supernatant from either PBMC or PMN treated with 1,2-benzopyrone. These results strongly suggested that 1,2-benzopyrone has an immunoenhancing effect on the OBA of PMN when phagocytic response occurred only. This enhanced OBA may be mediated through active humoral substance(s), such as $TNF-\alpha,$ produced by PBMC stimulated with 1,2-benzopyrone.

• Journal of Veterinary Clinics
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• v.39 no.2
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• pp.51-58
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• 2022

Quercetin, a flavonoid found in fruits and vegetables, exhibits a strong anti-inflammatory activity. The objective of this study was to examine the effect of quercetin on chemotactic activity of peripheral blood polymorphonuclear cells (PMNs) to culture supernatant from peripheral blood mononuclear cells (PBMCs) stimulated with lipopolysaccharide (LPS). In addition, we determined whether this effect is related to interleukin (IL)-8 and changes in cytoskeleton. The chemotactic activity of PMNs was evaluated by a modified Boyden chamber assay. Total cellular filamentous (F)-actin levels were measured by method of fluorescence microscopy. The levels of IL-8 mRNA and protein were measured by real time polymerase reaction method and enzyme-linked immunosorbent assay, respectively. Quercetin (0-50 µM) itself has no chemoattractant effect for PMNs. The culture supernatant from PBMCs (2 × 10⁶ cells/mL) treated with LPS (1 ㎍/mL) showed remarkable increase in chemotaxis of PMNs. However, this effect was reduced dose-dependently by treatment with quercetin. In addition, PBMCs treated with LPS revealed enhanced levels in IL-8 protein and mRNA. Co-treatment of LPS with quercetin (50 µM) in PBMCs decreased IL-8 production and expression. Treatment of quercetin (0-50 µM) on PMNs to rpIL-8 (10 nM) decreased dose-dependently the chemotactic activity of PMNs. Treatment of quercetin on PMNs to IL-8 also reduced their total cellular F-actin level. These results suggested that quercetin attenuates chemotactic activity of PMNs, which is mediated by down-regulation of IL-8 production from LPS-stimulated PBMCs and inhibition of F-actin polymerization in PMNs.