Plasmacytoid T cells: A cell population normally present in the reactive lymph node

Facchetti, Fabio; Wolf‐Peeters, Chris De; Oord, Joost J. van den; Vos, Rita De; Desmet, Valeer

doi:10.1016/s0046-8177(88)80091-1

Cited by 77 publications

(43 citation statements)

References 19 publications

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“…by guest www.bloodjournal.org From (for example, inflamed tonsils) or neoplastic lymphoid tissue. 46,47 More recently they have been found in human thymus. 48,49 However, under steady state pDCs are rare in periphery, outside lymphoid organs.…”

Section: Discussionmentioning

confidence: 99%

Human dendritic cell subsets in NOD/SCID mice engrafted with CD34+ hematopoietic progenitors

Palucka

Gatlin

Blanck

et al. 2003

Blood

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The discovery of in vitro culture systems yielding mouse 3 and human [4][5][6] DCs accelerated studies on their biology and led us to understand their complexity. Indeed, DCs have different functions at different stages of maturation. While immature (nonactivated) DCs that capture self-antigens (eg, apoptotic cells) induce tolerance, 7,8 mature antigen-loaded DCs induce antigen-specific immunity. Furthermore, several DC subsets exist that have different functions. 1 In humans, 2 major DC pathways have been described. A myeloid pathway includes Langerhans cells (LCs), found in stratified epithelia such as skin, and interstitial DCs (intDCs), found in all other tissues. While both subsets produce interleukin-12 (IL-12), only intDCs make IL-10 and induce B-cell proliferation and differentiation. 9 The other pathway includes the plasmacytoid DCs (pDCs), 10 which secrete large amounts of type I interferons within a few hours following viral encounter. 11,12 Depending on the maturation signal that they receive, pDCs modulate T-cell differentiation into either interferon-␥ (IFN-␥) or IL-4-producing CD4 T cells 13 or into regulatory CD8 T cells. 14 Thus, distinct human DC subsets differentially control lymphocytes in vitro.The in vitro generation of human DCs prompted their use in immunotherapy, particularly for the treatment of cancer. Early trials in humans have shown the safety of tumor-associated antigens (TAA)-loaded DCs as well as some clinical and immune responses (reviewed in Banchereau et al 15 ). We also are beginning to unravel the role of DCs in pathogenesis of human diseases, for example, thymic stroma lymphopoietin (TSLP)-triggered mDCs may play a key role in the initiation of allergic inflammation, 16 while IFN-␣-triggered mDCs appear as a major factor driving the autoimmune reaction in systemic lupus erythematosus. 17 Thus, DCs can be considered both as vectors and targets for immunomodulation.Understanding the specific functions of DC subsets and their interplay in vivo will be critical to understand the launching and modulation of immune responses. Hence, the need for preclinical models of the human immune system. Indeed, conclusions from studies in mice cannot be directly extrapolated to humans because of biologic differences as exemplified by the CD1 antigen presentation system that is different between species. 18 SCID mice reconstituted with human cells represent interesting candidates for human disease models [19][20][21] For personal use only. on May 12, 2018. by guest www.bloodjournal.org From Many of the difficulties encountered in these models could be due to insufficient reconstitution of human DCs, a parameter that has not been extensively studied. Given the key role that DCs play in T-cell homeostasis, 36 DC reconstitution might facilitate human T-lymphocyte reconstitution. Indeed, recent studies with ex vivogenerated monocyte-derived DCs suggest their capacity to support CD4 T-cell differentiation as well as humoral responses in vivo. 37,38 However, these adoptive transfer models do not p...

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Section: Discussionmentioning

confidence: 99%

Human dendritic cell subsets in NOD/SCID mice engrafted with CD34+ hematopoietic progenitors

Palucka

Gatlin

Blanck

et al. 2003

Blood

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“…IPCs share 2 important characteristics with CD4 ϩ T cells: (1) they express high levels of surface CD4 31 and (2) they can be found in blood, thymus, and secondary lymphoid organs 32 where HIV is able to replicate actively. 33 Moreover, they constitutively express the chemokine receptors CCR5 and CXCR4 (H Kanzler, unpublished data, 1999) that are the main coreceptors for HIV infection of a cell.…”

Section: Discussionmentioning

confidence: 99%

Depletion of circulating natural type 1 interferon-producing cells in HIV-infected AIDS patients

Soumelis

Scott

Gheyas

et al. 2001

Blood

343

282

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IntroductionA progressive reduction in CD4 ϩ T-helper lymphocytes is the main feature of HIV infection and leads to a depression in adaptive immunity. 1 Innate immunity is also important in the host response to HIV infection and can be impaired during the course of this infection. Dendritic cells (DCs) can promote HIV transmission, [2][3][4][5] and DC function 6 and number 7 decline with HIV infection. The effector functions of monocytes and macrophages, including phagocytosis and intracellular oxidative responses, can be found decreased in HIV-infected subjects 8,9 and in cultured cells in the presence of HIV. [10][11][12][13] Superoxide production by neutrophils 14 as well as natural killer cell function as measured by the lymphokineactivated killer activity and responsiveness to interferon-␣ (IFN-␣) 15,16 have been shown to be defective in HIV-infected subjects.An important part of the innate defense against virus is the production of the type I IFNs, IFN-␣, and IFN-␤. 17 IFN-␣/␤ not only directly inhibit HIV replication, 18-20 but also have important adjuvant effects on a variety of immune cell types, such as monocytes, natural killer cells, 21 and T cells. [22][23][24][25][26] The in vitro type I IFN production by total peripheral blood mononuclear cells (PBMCs) was shown to be impaired during the course of HIV infection, and this impairment was associated with the occurrence of opportunistic infections. 27,28 CD4 ϩ CD11c Ϫ lineage marker Ϫ type 2 DC precursors (pre-DC2) were recently shown to be the natural IFN-␣/␤-producing cells in human blood. 29,30 IPCs produce up to 1000 times more IFN-␣ than any other blood cell type in response to viral stimulation. 29 Whether this impairment of IFN-␣/␤ production in HIV-infected individuals is due to a functional defect or to a reduction in number of IPCs is not known.In this study, we show that blood IPCs are severely decreased in AIDS patients but increased in asymptomatic long-term survivors (LTSs). The drop in IPC number and a decrease in their induced IFN production are associated with the presence of opportunistic infections and active Kaposi sarcoma. Our findings bring a new insight into the physiopathology of HIV infection and identify the IPC count as a new parameter to monitor the status of the immune system of HIV-infected subjects. Patients, materials, and methods HIV-infected subjectsFifty-four HIV-infected subjects were recruited from 3 centers: the University of California at San Francisco (UCSF), the San Francisco General Hospital, and the Hospices Civils de Lyon, France. This study was approved by the Committee for Human Research, UCSF. Subjects were enrolled consecutively, and the only inclusion criterion was a confirmed HIVpositive serology and a written informed consent. The following conditions, which can nonspecifically affect blood cell counts, were used as exclusion criteria: previous cytotoxic chemotherapy, splenectomy, hypersplenism, and blood transfusion within the past 4 weeks. After inclusion, a full medical history was taken and physic...

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“…Whole blood was within 2 h mixed with a NH 4 Cl solution (16) at room temperature for 2-5 min to lyse the erythrocytes. The leukocytes were sedimented by centrifugation, washed once with PBS containing 1% FCS, and then subjected to multicolor immunofluorescence staining (see below).…”

Section: Preparation Of Blood Samplesmentioning

confidence: 99%

Experimentally Induced Recruitment of Plasmacytoid (CD123high) Dendritic Cells in Human Nasal Allergy

Jahnsen¹,

Lund-Johansen²,

Dunne

et al. 2000

The Journal of Immunology

251

215

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Recent evidence suggests that the previously enigmatic cell type designated plasmacytoid monocytes can function as dendritic cells and contribute substantially to both innate and adaptive immunity. This cell type has previously been described only in bone marrow, blood, and organized lymphoid tissue, but not at effector sites with direct Ag exposure such as the mucosae. Plasmacytoid dendritic cells (P-DCs) matured in vitro can induce T cells to produce allergy-promoting Th2 cytokines; therefore, their possible occurrence in nasal mucosa during experimentally elicited allergic rhinitis was examined. Patients with silent nasal allergy were challenged topically with relevant allergen daily for 7 days. Biopsy specimens as well as blood samples were obtained before and during such provocation, and P-DCs were identified by their high expression of CD123 (IL-3R α-chain), together with CD45RA. Our results showed that P-DCs were present in low and variable numbers in normal nasal mucosa but increased dramatically during the allergic reaction. This accumulation concurred with the expression of the L-selectin ligand peripheral lymph node addressin on the mucosal vascular endothelium. The latter observation was particularly interesting in view of the high levels of L-selectin on circulating P-DC precursors and of previous reports suggesting that these cells can enter organized lymphoid tissue via high endothelial venules (which express peripheral lymph node addressin constitutively). Together, our findings suggested that P-DCs are involved in the triggering of airway allergy and that they are directed to allergic lesions by adhesion molecules that normally mediate leukocyte extravasation in organized lymphoid tissue.

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Plasmacytoid T cells: A cell population normally present in the reactive lymph node

Cited by 77 publications

References 19 publications

Human dendritic cell subsets in NOD/SCID mice engrafted with CD34+ hematopoietic progenitors

Human dendritic cell subsets in NOD/SCID mice engrafted with CD34+ hematopoietic progenitors

Depletion of circulating natural type 1 interferon-producing cells in HIV-infected AIDS patients

Experimentally Induced Recruitment of Plasmacytoid (CD123high) Dendritic Cells in Human Nasal Allergy

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