Rimpei Morita

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Although a fraction of human blood memory CD4(+) T cells expresses chemokine (C-X-C motif) receptor 5 (CXCR5), their relationship to T follicular helper (Tfh) cells is not well established. Here we show that human blood CXCR5(+)CD4(+) T cells share functional properties with Tfh cells and appear to represent their circulating memory compartment. Blood(More)
Little is known about the functional differences between the human skin myeloid dendritic cell (DC) subsets, epidermal CD207(+) Langerhans cells (LCs) and dermal CD14(+) DCs. We showed that CD14(+) DCs primed CD4(+) T cells into cells that induce naive B cells to switch isotype and become plasma cells. In contrast, LCs preferentially induced the(More)
The dendritic cell (DC) system of antigen-presenting cells controls immunity and tolerance. DCs initiate and regulate immune responses in a manner that depends on signals they receive from microbes and their cellular environment. They allow the immune system to make qualitatively distinct responses against different microbial infections. DCs are composed of(More)
T follicular helper (Tfh) cells help development of antibody responses via interleukin-21 (IL-21). Here we show that activated human dendritic cells (DCs) induced naive CD4(+) T cells to become IL-21-producing Tfh-like cells through IL-12. CD4(+) T cells primed with IL-12 induced B cells to produce immunoglobulins in a fashion dependent on IL-21 and(More)
Post-ischemic inflammation is an essential step in the progression of brain ischemia-reperfusion injury. However, the mechanism that activates infiltrating macrophages in the ischemic brain remains to be clarified. Here we demonstrate that peroxiredoxin (Prx) family proteins released extracellularly from necrotic brain cells induce expression of(More)
Natural alpha interferon (IFN-alpha)-producing cells (IPCs) are now recognized as identical to plasmacytoid dendritic cell (DC) precursors in human blood and are thought to play an important role in antiviral immunity. In the present study, we examined the susceptibility as well as the cellular responses of IPCs to human immunodeficiency virus type 1(More)
Although it has been well established that TGF-beta plays a pivotal role in immune regulation, the roles of its downstream transcription factors, Smad2 and Smad3, have not been fully clarified. Specifically, the function of Smad2 in the immune system has not been investigated because of the embryonic lethality of Smad2-deficient mice. In this study, we(More)
Regulatory T cells (T(reg) cells) develop from progenitor thymocytes after the engagement of T cell antigen receptors (TCRs) with high-affinity ligands, but the underlying molecular mechanisms are still unclear. Here we show that the Nr4a nuclear receptors, which are encoded by immediate-early genes upregulated by TCR stimulation in thymocytes, have(More)
Inflammasome activation has been implicated in various inflammatory diseases including post-ischaemic inflammation after stroke. Inflammasomes mediate activation of caspase-1, which subsequently induces secretion of pro-inflammatory cytokines such as IL-1β and IL-18, as well as a form of cell death called pyroptosis. In this study, we report that Bruton's(More)
Mucosal immunoglobulin A (IgA) secreted by local plasma cells (PCs) is a critical component of mucosal immunity. Although IgA class switching can occur at mucosal sites, high-affinity PCs are optimally generated in germinal centers (GCs) in a T cell-dependent fashion. However, how CD4(+) helper T cells induce mucosal-homing IgA-PCs remains unclear. Here, we(More)