Abstract
GM-CSF stimulates the growth and differentiation of hematopoietic progenitors and also affects mature cell function. These effects have led to the use of GM-CSF as a vaccine adjuvant with promising results; however, the mechanisms underlying GM-CSF-mediated immune potentiation are incompletely understood. In this study, we investigated the hypothesis that the immune stimulatory role of GM-CSF is in part due to effects on class II MHC Ag presentation. We find that, in primary human monocytes treated for 24-48 h, GM-CSF increases surface class II MHC expression and decreases the relative level of the invariant chain-derived peptide, CLIP, bound to surface class II molecules. GM-CSF also increases expression of the costimulatory molecules CD86 and CD40, but not the differentiation marker CD1a or CD16. Furthermore, GM-CSF-treated monocytes are better stimulators in a mixed leukocyte reaction. Additional analyses of the class II pathway revealed that GM-CSF increases total protein and RNA levels of HLA-DR, DM, and DOalpha. Expression of class II transactivator (CIITA) types I and III, but not IV, transcripts increases in response to GM-CSF. Furthermore, GM-CSF increases the amount of CIITA associated with the DR promoter. Thus, our data argue that the proinflammatory role of GM-CSF is mediated in part through increased expression of key molecules involved in the class II MHC pathway via induction of CIITA.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Adjuvants, Immunologic / pharmacology
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Antigen Presentation / immunology
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Antigens, CD / biosynthesis
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Antigens, Differentiation, B-Lymphocyte / biosynthesis
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Antigens, Differentiation, B-Lymphocyte / genetics
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Antigens, Differentiation, B-Lymphocyte / metabolism
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B7-2 Antigen
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CD40 Antigens / biosynthesis
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Cell Differentiation / immunology
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Cell Membrane / immunology
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Cell Membrane / metabolism
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Cells, Cultured
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Down-Regulation / genetics
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Down-Regulation / immunology
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Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology*
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HLA-D Antigens / biosynthesis
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HLA-D Antigens / genetics
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HLA-D Antigens / metabolism*
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HLA-D Antigens / physiology
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HLA-DR Antigens / biosynthesis
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HLA-DR Antigens / genetics
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HLA-DR Antigens / metabolism
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HLA-DR alpha-Chains
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Histocompatibility Antigens Class II / biosynthesis
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Histocompatibility Antigens Class II / genetics
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Histocompatibility Antigens Class II / metabolism
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Humans
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Interferon-gamma / biosynthesis
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Interferon-gamma / pharmacology
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Interleukin-10 / antagonists & inhibitors
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Interleukin-10 / biosynthesis
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Membrane Glycoproteins / biosynthesis
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Monocytes / cytology
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Monocytes / immunology*
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Monocytes / metabolism
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Promoter Regions, Genetic
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RNA, Messenger / biosynthesis
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Recombinant Proteins
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Signal Transduction / genetics
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Signal Transduction / immunology*
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Transcription, Genetic / immunology
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Up-Regulation / genetics
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Up-Regulation / immunology
Substances
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Adjuvants, Immunologic
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Antigens, CD
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Antigens, Differentiation, B-Lymphocyte
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B7-2 Antigen
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CD40 Antigens
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CD86 protein, human
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HLA-D Antigens
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HLA-DM antigens
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HLA-DO antigens
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HLA-DR Antigens
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HLA-DR alpha-Chains
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Histocompatibility Antigens Class II
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Membrane Glycoproteins
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RNA, Messenger
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Recombinant Proteins
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invariant chain
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Interleukin-10
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Interferon-gamma
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Granulocyte-Macrophage Colony-Stimulating Factor