Effect of in vitro and in vivo administration of dexamethasone on rat macrophage functions: comparison between alveolar and peritoneal macrophages

Nakamura, Yuko; Murai, Toshimi; Ogawa, Youichi

doi:10.1183/09031936.96.09020301

Cited by 38 publications

(24 citation statements)

References 19 publications

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“…The results showed that dexamethasone had no effect on the phagocytic activity of alveolar macrophages. This observation is contradictory to the previous report of Nakamura et al in that dexamethasone was found to suppress the phagocytic activity of alveolar macrophages in their study (36). A careful comparison of the immunosuppression protocols revealed that Nakamura et al used 4 to 50 times more dexamethasone (1.25 to 20 mg/kg/day) than we did in the present study, in which rats were immunosuppressed with 0.36 mg/kg/day.…”

Section: Discussioncontrasting

confidence: 56%

Effect of Bronchoalveolar Lavage Fluid fromPneumocystis carinii- Infected Hosts on Phagocytic Activity of Alveolar Macrophages

et al. 2004

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Alveolar macrophages from Pneumocystis carinii-infected rats are defective in phagocytosis. To investigate whether this defect is due to a certain factor present in P. carinii-infected lungs, alveolar macrophages from uninfected rats were incubated with bronchoalveolar lavage (BAL) fluid samples from P. carinii-infected rats. Alveolar macrophages treated with these BAL fluid samples became defective in phagocytosis but remained normal when treated with BAL fluid samples from noninfected or Toxoplasma gondii-infected rats. The suppressive activity of the BAL fluid samples from P. carinii-infected rats on phagocytosis was retained when the BAL fluid samples were passed through a filter with a pore size of 0.45 m but was lost when the BAL fluid samples were digested with proteases such as trypsin, pepsin, papain, or endopeptidase Gly-C. Lipid fractions of these BAL fluid samples had no suppressive activity on phagocytosis. The suppressive activity of these BAL fluid samples was also lost when they were incubated with concanavalin A-agarose beads, suggesting that the inhibitor is a glycoprotein. The inhibitor was estimated to be larger than 100,000 Da by exclusion filtration. After binding to the concanavalin A-agarose beads, the inhibitor in BAL fluid samples and P. carinii lysate could be eluted with 200 mM methylmannose. Treatment of both the crude BAL fluid samples and P. carinii lysate and the 200 mM methylmannose eluate with antibody against the major surface glycoprotein of P. carinii eliminated their suppressive activity. These results suggest that the factor capable of suppressing the phagocytic activity of alveolar macrophages is P. carinii major surface glycoprotein or one or more of its derivatives.An important function of alveolar macrophages is to clear foreign particles and infectious agents from the lung. Their role in the defense against Pneumocystis carinii infection is demonstrated by the observation that transtracheally inoculated P. carinii organisms are not cleared in alveolar macrophage-depleted rats (31). Administration of granulocyte-macrophage colony-stimulating factor, which activates alveolar macrophages (40), decreases the severity of P. carinii pneumonia (34). This finding also indicates the importance of alveolar macrophages in the clearance of Pneumocystis organisms.The alveoli are constantly exposed to foreign material and microorganisms. The alveolar macrophage maintains a low level of activation to engulf and destroy these materials while inhibiting an overly reactive inflammatory reaction to foreign objects encountered. To accomplish this, alveolar macrophages inhibit antigen presentation by dendritic cells (20), limit the expansion of lymphocyte populations (38), and restrict pulmonary lymphocyte functions (19). When activated, alveolar macrophages become proinflammatory and produce interleukin-8, which attracts neutrophils and lymphocytes by chemotaxis, as well as interleukin-1␤, tumor necrosis factor alpha, interleukin-6, and granulocyte-macrophage colony-stimulating factor, wh...

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Section: Discussioncontrasting

confidence: 56%

Effect of Bronchoalveolar Lavage Fluid fromPneumocystis carinii- Infected Hosts on Phagocytic Activity of Alveolar Macrophages

et al. 2004

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“…It decreases the numbers of MHC class II cells in chickens (Isobe and Lillehoj, 1993) and reduces the immunostimulatory capacity of dendritic cells in mammals (Lim et al, 1996). Numerous in vitro studies have shown that dexamethasone inhibits the production of certain immune cytokines by macrophages and microglia (e.g., Ganter et al, 1992;Nakamura et al, 1996). Dexamethasone inhibits macrophage activation and cytokine production in mammals and birds (e.g., Russo-Marie, 1992;Corrier et al, 1991;Isobe and Lillehoj, 1992;Hubner et al, 1996).…”

Section: Benefits Of Leukocyte Subtype Identification In Inner Ear Sementioning

confidence: 97%

Characterization of leukocyte subtypes in chicken inner ear sensory epithelia

O'Halloran

Oesterle

2004

J of Comparative Neurology

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Human hearing and balance require intact inner ear sensory hair cells, which transduce mechanical stimuli into electrical signals that are transmitted to the brain. Loss of hair cells after birth in mammals is irreversible, whereas birds are able to regenerate hair cells after insult and demonstrate ongoing hair cell production in the vestibular epithelia. Leukocytes reside in undamaged sensory epithelia of the avian inner ear and increase in number after trauma, prior to the proliferation of hair cell progenitors. It has been hypothesized that leukocyte-produced growth factors or cytokines may be involved in triggering hair cell regeneration. Little is known about the specific leukocyte subtypes present in avian ear. Immunohistochemistry with a panel of monoclonal antibodies to chicken leukocytes was used to identify leukocyte subtypes in normal posthatch chicken ear sensory epithelia. The responsiveness of the leukocytes to aminoglycoside-induced damage was also observed. Based on immunocytochemical and morphological criteria, we quantified leukocyte subtypes in normal and drug-damaged auditory and vestibular sensory epithelia. Data indicate that lymphocytes (B and T cells) do not reside in normal or drug-damaged ear sensory epithelia at 1-3 days post insult but are present in adjacent nonsensory tissues. The most common leukocytes in inner ear sensory epithelia are ramified cells of the myeloid lineage. Many of these are MHC class II positive, and a small percentage are mature tissue macrophages. An absence of leukocytes in lesioned areas of the auditory sensory epithelium suggests they may not play a critical role in triggering hair cell regeneration.

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“…After incubation for 48 or 72 h with calcitriol, the cells were plated in a 24-well plate at 10 6 cells/0.9 ml/well, and 0.1 ml of endotoxin at various concentrations was added to each well. The cell suspensions were incubated for 17 h at 37°C, and then the supernatants were assayed for TNF-␣ by a cytotoxicity assay with L929 cells (obtained from Japanese Cancer Research Resources Bank-Cell) as previously described (22).…”

Section: Methodsmentioning

confidence: 99%

Evaluation of the In Vitro Pyrogen Test System Based on Proinflammatory Cytokine Release from Human Monocytes: Comparison with a Human Whole Blood Culture Test System and with the Rabbit Pyrogen Test

Nakagawa

Maeda

Murai

2002

Clin Vaccine Immunol

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The reliability of an in vitro pyrogen test system based on proinflammatory cytokine release from human monocytic cells was assessed by comparison with a test system based on a human whole blood culture as well as with the conventional rabbit pyrogen test. The human cells used as the pyrogen indicator cells were newly selected by subcloning of a human monocytic cell line, Mono-Mac-6. The selected cells, named MM6-CA8, responded to various pyrogens, including endotoxin, peptidoglycan (PG), Staphylococcus aureus Cowan 1 (SAC), and poly(I · C), with a high sensitivity and produced proinflammatory cytokines, such as interleukin 1 (IL-1), IL-6, and tumor necrosis factor alpha. Among these cytokines, IL-6 was produced most sensitively in response to traces of the pyrogens and detected in the largest quantities in the culture medium. The cytokineproducing responses of MM6-CA8 cells correlated significantly with the responses of cultured human whole blood, which represents an ex vivo culture test system reproducing pyrogen-induced cytokine production in the human body. In terms of cytokine inducibility, the pyrogens were ranked in the order endotoxin > PG > poly (I · C) > SAC in both culture systems, a ranking which almost agreed with the ranking of their pyrogenicity as assessed by the rabbit pyrogen test. These results suggest that the in vitro responsiveness of MM6-CA8 cells to various pyrogens is highly relevant for human pyrogenic reactions. Therefore, the in vitro test system is useful and reliable for detecting the presence of materials that are pyrogenic for humans.

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Effect of in vitro and in vivo administration of dexamethasone on rat macrophage functions: comparison between alveolar and peritoneal macrophages

Cited by 38 publications

References 19 publications

Effect of Bronchoalveolar Lavage Fluid fromPneumocystis carinii- Infected Hosts on Phagocytic Activity of Alveolar Macrophages

Effect of Bronchoalveolar Lavage Fluid fromPneumocystis carinii- Infected Hosts on Phagocytic Activity of Alveolar Macrophages

Characterization of leukocyte subtypes in chicken inner ear sensory epithelia

Evaluation of the In Vitro Pyrogen Test System Based on Proinflammatory Cytokine Release from Human Monocytes: Comparison with a Human Whole Blood Culture Test System and with the Rabbit Pyrogen Test

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