Toll-like receptor and cytokine expression patterns of CD56+ T cells are similar to natural killer cells in response to infection with Venezuelan equine encephalitis virus replicons.
Using the natural killer (NK) cell-surface marker CD56 to study NK T cells in peripheral blood, we found that their frequency in mononuclear cells among healthy individuals was 1%-20% (average, 7.3%) and sporadically increased 4-5-fold within individuals over the course of 8 months. Infection of mononuclear cells in vitro with Venezuelan equine encephalitis virus replicon particles (VRPs) resulted in a significant increase in CD56(+) T cells and in the expression of interferon-alpha, tumor necrosis factor (TNF)-alpha, and interferon-gamma by CD56(+) but not CD56(-) T cells. NK and CD56(+) T cells expressed higher levels of Toll-like receptor (TLR)-3 and TLR4 after infection with VRPs, whereas only NK cells expressed inducible TNF-alpha and TLR2. Most of these effects were duplicated by activating mononuclear cells with double-stranded RNA. These expression patterns indicate that T cells coexpressing NK markers respond like NK cells to viral infection or double-stranded RNA, potentially fulfilling innate and adaptive immune functions.
Saikh
Kamal U
KU
Laboratory of Molecular Immunology, US Army Medical Research Institute of Infectious Diseases, Frederick, Maryland 21702, USA. Kamal.Saikh@DET.AMEDD.ARMY.MIL.
Lee
John S
JS
Kissner
Teri L
TL
Dyas
Beverly
B
Ulrich
Robert G
RG
D000818:Animals; D019002:CD56 Antigen / Q000276:immunology*; D006224:Cricetinae; D016207:Cytokines / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D004666:Encephalitis Virus, Venezuelan Equine / Q000235:genetics / Q000276:immunology*; D005434:Flow Cytometry; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D008562:Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D012313:RNA / Q000737:chemistry / Q000235:genetics; D012330:RNA, Double-Stranded / Q000276:immunology; D011956:Receptors, Cell Surface / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology*; D012093:Replicon / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000276:immunology* / Q000378:metabolism / Q000821:virology; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors
D019002:CD56 Antigen; D016207:Cytokines; D008562:Membrane Glycoproteins; D012330:RNA, Double-Stranded; D011956:Receptors, Cell Surface; C495342:TLR2 protein, human; C495344:TLR3 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051196:Toll-Like Receptor 3; D051197:Toll-Like Receptor 4; D051193:Toll-Like Receptors; D012313:RNA