Abstract
Inhibition of T-cell responses in tumor microenvironments by myeloid-derived suppressor cells (MDSCs) is widely accepted. We demonstrated augmentation of monocytic MDSCs whose suppression of not only T-cell, but also B-cell, responsiveness paralleled the immunodeficiency during LP-BM5 retrovirus infection. MDSCs inhibited T cells by inducible nitric oxide synthase (iNOS)/nitric oxide (NO), but uniquely, inhibition of B cells was ~50% dependent each on iNOS/NO and the MDSC-expressed negative-checkpoint regulator VISTA. Blockade with a combination of iNOS/NO and VISTA caused additive or synergistic abrogation of MDSC-mediated suppression of B-cell responsiveness.
Copyright © 2015, American Society for Microbiology. All Rights Reserved.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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B-Lymphocytes / immunology*
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B-Lymphocytes / pathology
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Immunologic Deficiency Syndromes / genetics
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Immunologic Deficiency Syndromes / immunology*
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Immunologic Deficiency Syndromes / pathology
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Membrane Proteins / genetics
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Membrane Proteins / immunology*
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Mice
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Monocytes / immunology*
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Monocytes / pathology
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Nitric Oxide / genetics
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Nitric Oxide / immunology
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Nitric Oxide Synthase Type II / genetics
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Nitric Oxide Synthase Type II / immunology
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Retroviridae Infections / genetics
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Retroviridae Infections / immunology*
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Retroviridae Infections / pathology
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T-Lymphocytes / immunology
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T-Lymphocytes / pathology
Substances
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Membrane Proteins
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Vsir protein, mouse
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Nitric Oxide
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Nitric Oxide Synthase Type II
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Nos2 protein, mouse