Jakob Michaëlsson

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Natural killer (NK) cells are lymphocytes of the innate immune system that, following differentiation from CD56(bright) to CD56(dim) cells, have been thought to retain fixed functional and phenotypic properties throughout their lifespan. In contrast to this notion, we here show that CD56(dim) NK cells continue to differentiate. During this process, they(More)
As the immune system develops, T cells are selected or regulated to become tolerant of self antigens and reactive against foreign antigens. In mice, the induction of such tolerance is thought to be attributable to the deletion of self-reactive cells. Here, we show that the human fetal immune system takes advantage of an additional mechanism: the generation(More)
Regulatory T (T(R)) cells maintain tolerance to self-antigens and control immune responses to alloantigens after organ transplantation. Here, we show that CD4(+) CD25(+) human T(R) cells suppress virus-specific T-cell responses. Depletion of T(R) cells from peripheral blood mononuclear cells enhances T-cell responses to cytomegalovirus and human(More)
Human natural killer (NK) cells are functionally regulated by killer cell immunoglobulin-like receptors (KIRs) and their interactions with HLA class I molecules. As KIR expression in a given NK cell is genetically hard-wired, we hypothesized that KIR repertoire perturbations reflect expansions of unique NK-cell subsets and may be used to trace adaptation of(More)
Human histocompatibility leukocyte antigen (HLA)-E is a nonclassical major histocompatibility complex (MHC) class I molecule which presents a restricted set of nonameric peptides, derived mainly from the signal sequence of other MHC class I molecules. It interacts with CD94/NKG2 receptors expressed on the surface of natural killer (NK) cells and T cell(More)
Expression of inhibitory killer cell immunoglobulin-like receptors (KIRs) specific for self-major histocompatibility complex (MHC) class I molecules provides an educational signal that generates functional natural killer (NK) cells. However, the effects of activating KIRs specific for self-MHC class I on NK-cell education remain elusive. Here, we provide(More)
Natural killer (NK) cells are known to mount a rapid response to several virus infections. In experimental models of acute viral infection, this response has been characterized by prompt NK cell activation and expansion followed by rapid contraction. In contrast to experimental model systems, much less is known about NK cell responses to acute viral(More)
The lack of natural killer (NK) cell-specific markers, as well as the overlap among several common surface antigens and functional properties, has obscured the delineation between NK cells and dendritic cells. Here, novel subsets of peripheral blood CD3/14/19(neg) NK cells and monocyte/dendritic cell (DC)-like cells were identified on the basis of CD7 and(More)
The live attenuated yellow fever virus (YFV) 17D vaccine provides a good model to study immune responses to an acute viral infection in humans. We studied the temporal dynamics, composition, and character of the primary human T cell response to YFV. The acute YFV-specific effector CD8 T cell response was broad and complex; it was composed of dominant(More)
CD4+CD25high regulatory T (TReg) cells modulate antigen-specific T cell responses, and can suppress anti-viral immunity. In HTLV-1 infection, a selective decrease in the function of TReg cell mediated HTLV-1-tax inhibition of FOXP3 expression has been described. The purpose of this study was to assess the frequency and phenotype of TReg cells in HTLV-1(More)