Abstract
Prolonged exposure of CD8+ T cells to antigenic stimulation, as in chronic viral infections, leads to a state of diminished function termed exhaustion. We now demonstrate that even during exhaustion there is a subset of functional CD8+ T cells defined by surface expression of SIRPα, a protein not previously reported on lymphocytes. On SIRPα+ CD8+ T cells, expression of co-inhibitory receptors is counterbalanced by expression of co-stimulatory receptors and it is only SIRPα+ cells that actively proliferate, transcribe IFNγ and show cytolytic activity. Furthermore, target cells that express the ligand for SIRPα, CD47, are more susceptible to CD8+ T cell-killing in vivo. SIRPα+ CD8+ T cells are evident in mice infected with Friend retrovirus, LCMV Clone 13, and in patients with chronic HCV infections. Furthermore, therapeutic blockade of PD-L1 to reinvigorate CD8+ T cells during chronic infection expands the cytotoxic subset of SIRPα+ CD8+ T cells.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, N.I.H., Intramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Arenaviridae Infections / genetics
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Arenaviridae Infections / immunology*
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Arenaviridae Infections / virology
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CD8-Positive T-Lymphocytes / immunology*
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CD8-Positive T-Lymphocytes / metabolism
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CD8-Positive T-Lymphocytes / virology
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Female
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Gene Expression / immunology
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Gene Expression Profiling
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Host-Pathogen Interactions / immunology
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Humans
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Lymphocyte Activation / genetics
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Lymphocyte Activation / immunology
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Lymphocytic Choriomeningitis / genetics
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Lymphocytic Choriomeningitis / immunology*
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Lymphocytic Choriomeningitis / virology
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Lymphocytic choriomeningitis virus / immunology*
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Lymphocytic choriomeningitis virus / physiology
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Mice, Inbred C57BL
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Mice, Transgenic
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Receptors, Immunologic / genetics
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Receptors, Immunologic / immunology*
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Receptors, Immunologic / metabolism
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T-Lymphocytes, Cytotoxic / immunology
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T-Lymphocytes, Cytotoxic / metabolism
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T-Lymphocytes, Cytotoxic / virology
Substances
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Ptpns1 protein, mouse
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Receptors, Immunologic