A subset of neutrophils in human systemic inflammation inhibits T cell responses through Mac-1
Janesh Pillay, … , Peter Pickkers, Leo Koenderman
Janesh Pillay, … , Peter Pickkers, Leo Koenderman
Published December 12, 2011
Citation Information: J Clin Invest. 2012;122(1):327-336. https://doi.org/10.1172/JCI57990.
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Research Article Immunology

A subset of neutrophils in human systemic inflammation inhibits T cell responses through Mac-1

Abstract

Suppression of immune responses is necessary to limit damage to host tissue during inflammation, but it can be detrimental in specific immune responses, such as sepsis and antitumor immunity. Recently, immature myeloid cells have been implicated in the suppression of immune responses in mouse models of cancer, infectious disease, bone marrow transplantation, and autoimmune disease. Here, we report the identification of a subset of mature human neutrophils (CD11cbright/CD62Ldim/CD11bbright/CD16bright) as what we believe to be a unique circulating population of myeloid cells, capable of suppressing human T cell proliferation. These cells were observed in humans in vivo during acute systemic inflammation induced by endotoxin challenge or by severe injury. Local release of hydrogen peroxide from the neutrophils into the immunological synapse between the neutrophils and T cells mediated the suppression of T cell proliferation and required neutrophil expression of the integrin Mac-1 (αMβ2). Our data demonstrate that suppression of T cell function can be accomplished by a subset of human neutrophils that can be systemically induced in response to acute inflammation. Identification of the pivotal role of neutrophil Mac-1 and ROS in this process provides a potential target for modulating immune responses in humans.

Authors

Janesh Pillay, Vera M. Kamp, Els van Hoffen, Tjaakje Visser, Tamar Tak, Jan-Willem Lammers, Laurien H. Ulfman, Luke P. Leenen, Peter Pickkers, Leo Koenderman

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Figure 6

Visualization of neutrophil-lymphocyte interactions.

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Visualization of neutrophil-lymphocyte interactions. CD62Ldim-sorted neu...
CD62Ldim-sorted neutrophils stained with CD16 FITC were added in a 2:1 ratio to unlabeled PBMCs and stimulated with PHA (10 μg/ml). Cells were incubated in culture medium containing Amplex Red (50 μM) and HRP (0.5 U/ml). Images were acquired using a Zeiss LSM510 Meta microscope. (A) Neutrophil-lymphocyte interaction with a localized Amplex Red signal indicative for local production of H2O2. (B) Same interaction as in A, showing that the Amplex Red signal colocalized with the CD16-labeled neutrophil membrane. The green line represents CD16; the red line represents H2O2. (C) Time-lapse image of a neutrophil-lymphocyte interaction. See Supplemental Video 1 for the full video. Representative examples are shown of 4 independent experiments. Original magnification, ×40 (A–C). (D) Quantification of local production of H2O2 spots in time-lapse images. Time-lapse images were made by deconvolution microscopy (Applied Precision DeltaVision Core Imaging System; the camera used was a Cascade EMCCD). CD62Ldim- and CD16dim-sorted neutrophils stained with calcein were added in a 2:1 ratio to unlabeled lymphocytes and stimulated with PHA (10 μg/ml). Cells were incubated in culture medium containing Amplex UltraRed (50 μM) and HRP (0.5 U/ml). In one of the conditions, Mac-1–blocking antibody 44a was added. The number of H2O2-positive spots were counted. Data are presented as mean ± SEM of 3 independent experiments. *P < 0.05.