Human effector CD8+ T lymphocytes express TLR3 as a functional coreceptor.
TLR are evolutionarily conserved molecules that play a key role in the initiation of innate antimicrobial immune responses. Through their influence on dendritic cell maturation, these receptors are also thought to indirectly shape the adaptive immune response. However, no data are currently available regarding both TLR expression and function in human CD8+ T cell subsets. We report that a subpopulation of CD8+ T cells, i.e., effector, but neither naive nor central memory cells, constitutively expresses TLR3. Moreover, the ligation of the receptor by a specific agonist in TLR3-expressing CD8+ T cells increased IFN-gamma secretion induced by TCR-dependent and -independent stimulation, without affecting proliferation or specific cytolytic activity. These results thereby suggest that TLR3 ligands can not only indirectly influence the adaptive immune response through modulation of dendritic cell activation, but also directly increase IFN-gamma production by Ag-specific CD8+ T cells. Altogether, the present work might open new perspectives for the use of TLR ligands as adjuvants for immunotherapy.
Tabiasco
Julie
J
Division of Clinical Onco-Immunology, Ludwig Institute for Cancer Research, Lausanne Branch, University Hospital (Centre Hospitalier Universitaire Vaudois), Avenue Pierre-Decker 4, 1005 Lausanne, Switzerland.
Devêvre
Estelle
E
Rufer
Nathalie
N
Salaun
Bruno
B
Cerottini
Jean-Charles
JC
Speiser
Daniel
D
Romero
Pedro
P
D018414:CD8-Positive T-Lymphocytes / Q000276:immunology* / Q000378:metabolism*; D049109:Cell Proliferation; D003602:Cytotoxicity, Immunologic; D006801:Humans; D007113:Immunity, Innate; D007371:Interferon-gamma / Q000378:metabolism; D008024:Ligands; D037182:T-Cell Antigen Receptor Specificity; D051196:Toll-Like Receptor 3 / Q000819:agonists / Q000276:immunology* / Q000502:physiology
D008024:Ligands; C495344:TLR3 protein, human; D051196:Toll-Like Receptor 3; D007371:Interferon-gamma