Accessory Cell Function of Human Alveolar Macrophages in Antigen-Induced T Lymphocyte Proliferation

Ohtsuka, Morio; Yoshizawa, Yasuyuki; Sato, Tetsuo; Yano, Heiichi; Mukai, Ryozaburo; Hasegawa, Shizuo; Moore, Vernon L.

doi:10.1159/000235007

Cited by 3 publications

(3 citation statements)

References 13 publications

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“…Although T cell suppression by alveolar M 4 in vitro has generally been shown to be dependent on high Mq5: T cell ratios [43,44,53], the mechanism of the suppression has not been elucidated. In vitro, alveolar M4 are capable of blocking early T cell activation events in a reversible fashion, dependent on cell-cell contact [53].…”

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confidence: 99%

Macrophage Suppression of T Cell Activation: A Potential Mechanism of Peripheral Tolerance

Attwood

Munn

1999

International Reviews of Immunology

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The mechanisms of induction and maintenance of tolerance in self-reactive T cells in the periphery are poorly understood. Current models assume that successful T cell activation only occurs if ligation of the T cell receptor (signal 1) by antigen presenting cells (APCs) is accompanied by a costimulatory signal (signal 2), and that signal 1 in the absence of signal 2 is either ignored or is tolerizing. However, there is also evidence for the existence of macrophages (M phi) capable of suppressing T cell activation both in vitro and in vivo. The possibility of a more actively induced tolerance exists, in which the M phi itself responds to T cell-mediated signals in a tolerogenic fashion. This would help to resolve the paradox that tissue M phi, which act as scavengers of self-antigen, can also act as professional APCs. The ability of tissue macrophages to actively suppress T cells would further underscore the importance of the innate immune system in regulating adaptive immune responses.

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confidence: 99%

Macrophage Suppression of T Cell Activation: A Potential Mechanism of Peripheral Tolerance

Attwood

Munn

1999

International Reviews of Immunology

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“…The AM may even suppress T cell responses, as shown particularly at high AM/T cell ratios [2,[9][10][11][12].…”

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confidence: 99%

“…The majority of studies with human bronchoalveolar lavage (BAL) cells of normal subjects showed that alveolar macrophages (AM) generally function poorly as antigen-presenting cells in T cell responses compared with blood monocytes or macrophages from other tissues [1][2][3][4], although a high percentage of human AM express HLA-D region antigens [5][6][7][8]. The AM may even suppress T cell responses, as shown particularly at high AM/T cell ratios [2,[9][10][11][12].…”

Section: Introductionmentioning

confidence: 99%

Enrichment and characterization of dendritic cells from human bronchoalveolar lavages

Havenith

Haarst

Breedijk

et al. 1994

Clinical and Experimental Immunology

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SUMMARYIn the present study about 0-3% to 1-6% of human bronchoalveolar lavage (BAL) cells were identified as typical dendritic cells (DC), having an irregular outline, lobulated nucleus, and clear distinguishable acid phosphatase activity or EBM11 (anti-CD68) reactivity in a spot near the nucleus. After DC enrichment, using transient adherence to plastic, FcR-panning, and a density metrizamide gradient, a population containing 7-8% typical DC was obtained. This DC-enriched low density fraction, containing the highest percentages of DC, very strongly induced T cell proliferation in an aliogeneic mixed leucocyte reaction (MLR), which was significantly higher than that induced by other partly (un)fractionated BAL cells. These data indicate that DC seem to be the major accessory cells in the BAL fiuid, and therefore may be important in the regulation ofT cell immune responses in the lung.

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Antiretroviral treatment reverses HIV-induced reduction in the expression of surface antigens on alveolar macrophages in AIDS patients

Bray

Squire

Kawana

et al. 1993

Clinical and Experimental Immunology

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StMMARYMoAbs and itnmunopcroxidasc tiielhods were used to Identify antigen-presenting and phagocytic cells and lo assess expression of HLA-DR molecules on cells obtained by bronehoalveolar iavagc (BAD from 33 AIDS patients and nine normal volunteers. In I7patienls, not receiving antiretroviral Iherapy, lhe expression of HLA-DR tnoleeulcs (MoAb RFDRl) as well as the percentages oi'eells expressing RFDI marker for antigen-presenting cells and RFD7 marker for mature phagocytes were significantly rcdueed. However, in BAL obtained after commencing treatment with zidovudine (AZT)in2l patients or with 2'.3'-dideoxyinosinc(DDI)in five patients, the expression of the tnarkers studied was found to have returned to levels of expression seen in normal lavages. The changes observed were clearly associated with antirelroviral treatment and did tioteorrelale with applications ofother drugs, blood CD4 counts or presence of infectious organisms in BAL fluid. As lhe alterations in the expression of HLA-DR molecules and RFDI marker on macrophages have been shown lo be assoeialed wiih functional capacities of these cells, the reversal of impaired expression ofphenolypic markers on alveolar macrophages in A IDS patients by AZT and DDI signifies an important ability of these drugs to modify immune reactivity and emphasizes the need to monitor such functions in HIV disease. treatment reduces frequency of opportunistic infections [9.10], but il is not known whether antirelroviral treatment can alTeel functional capacities of maerophages. In order to establish lhe effect of such treatment, we studied the expression of cell markers, believed lo be associated wiih function on alveolar macrophages in three groups of HIV-infected patients presenting with pneumonitis; (i) individuals not receivinganliretroviral drugs, and (ii) patients treated with AZT, or (iii) with 2',3'-dideoxyinosine (DDI), Keywords MATERIALS AND METHODS Brtincliotilrciiltir linage and study popidaiionBronchoalveotar lavagc (BAL) of lhe appropriate lobe (as indicated by radiographic abnormality) or of the right middle lobe (in palients wiih normal radiographs or generalized radiographic shadowing) was carried out using a fibreopiie bronchoscopc. A subsegmcntal bronchus was anaesthetized using 2",. lignoeaine and lavaged with 20-ml aliquots of O9'M, saline (buffered to pH 7-4 with NaHCO,) to a loial of 180 ml. The lavage fluid was gently aspirated after each aliquot and collected into a sterile, siliconizcd glass bottle maintained at 4 C. 13

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Accessory Cell Function of Human Alveolar Macrophages in Antigen-Induced T Lymphocyte Proliferation

Cited by 3 publications

References 13 publications

Macrophage Suppression of T Cell Activation: A Potential Mechanism of Peripheral Tolerance

Macrophage Suppression of T Cell Activation: A Potential Mechanism of Peripheral Tolerance

Enrichment and characterization of dendritic cells from human bronchoalveolar lavages

Antiretroviral treatment reverses HIV-induced reduction in the expression of surface antigens on alveolar macrophages in AIDS patients

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