Abstract
Marginal zone (MZ) B cells produce broad-spectrum antibodies that protect against infection early in life. In some instances, antibody production requires MZ B cells to display pathogen antigens bound to major histocompatibility complex class II (MHC II) molecules to T cells. We describe the trogocytic acquisition of these molecules from conventional dendritic cells (cDCs). Complement component 3 (C3) binds to murine and human MHC II on cDCs. MZ B cells recognize C3 with complement receptor 2 (CR2) and trogocytose the MHC II-C3 complexes, which become exposed on their cell surface. The ubiquitin ligase MARCH1 limits the number of MHC II-C3 complexes displayed on cDCs to prevent their elimination through excessive trogocytosis. Capture of C3 by MHC II thus enables the transfer of cDC-like properties to MZ B cells.
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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Adult
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Animals
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Antigen Presentation
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B-Lymphocytes / immunology*
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B-Lymphocytes / metabolism
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Cell Membrane / metabolism
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Complement Activation
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Complement C3 / immunology
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Complement C3 / metabolism*
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Dendritic Cells / immunology*
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Dendritic Cells / metabolism
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Female
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HLA-D Antigens / immunology
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HLA-D Antigens / metabolism
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Histocompatibility Antigens Class II / metabolism
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Humans
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Lymphoid Tissue / immunology*
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Male
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Mice
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Mice, Inbred BALB C
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Mice, Inbred C3H
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Mice, Inbred C57BL
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Middle Aged
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Receptors, Complement 3d / immunology
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Receptors, Complement 3d / metabolism
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T-Lymphocytes / immunology
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Trogocytosis*
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Ubiquitin-Protein Ligases / genetics
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Ubiquitin-Protein Ligases / metabolism
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Ubiquitination
Substances
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C3 protein, human
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Complement C3
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HLA-D Antigens
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Histocompatibility Antigens Class II
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Receptors, Complement 3d
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MARCH1 protein, mouse
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MARCHF1 protein, human
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Ubiquitin-Protein Ligases