Publications by Year: 2006

2006
Bonasio R, Scimone LM, Schaerli P, Grabie N, Lichtman AH, von Andrian UH. Clonal deletion of thymocytes by circulating dendritic cells homing to the thymus. Nat Immunol. 2006;7 (10) :1092-100.Abstract
Dendritic cell (DC) presentation of self antigen to thymocytes is essential to the establishment of central tolerance. We show here that circulating DCs were recruited to the thymic medulla through a three-step adhesion cascade involving P-selectin, interactions of the integrin VLA-4 with its ligand VCAM-1, and pertussis toxin-sensitive chemoattractant signaling. Ovalbumin-specific OT-II thymocytes were selectively deleted after intravenous injection of antigen-loaded exogenous DCs. We documented migration of endogenous DCs to the thymus in parabiotic mice and after painting mouse skin with fluorescein isothiocyanate. Antibody to VLA-4 blocked the accumulation of peripheral tissue-derived DCs in the thymus and also inhibited the deletion of OT-II thymocytes in mice expressing membrane-bound ovalbumin in cardiac myocytes. These findings identify a migratory route by which peripheral DCs may contribute to central tolerance.
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Chen Q, Fisher DT, Clancy KA, Gauguet J-MM, Wang W-C, Unger E, Rose-John S, von Andrian UH, Baumann H, Evans SS. Fever-range thermal stress promotes lymphocyte trafficking across high endothelial venules via an interleukin 6 trans-signaling mechanism. Nat Immunol. 2006;7 (12) :1299-308.Abstract
Fever is an evolutionarily conserved response during acute inflammation, although its physiological benefit is poorly understood. Here we show thermal stress in the range of fever temperatures increased the intravascular display of two 'gatekeeper' homing molecules, intercellular adhesion molecule 1 (ICAM-1) and CCL21 chemokine, exclusively in high endothelial venules (HEVs) that are chief portals for the entry of blood-borne lymphocytes into lymphoid organs. Enhanced endothelial expression of ICAM-1 and CCL21 was linked to increased lymphocyte trafficking across HEVs. A bifurcation in the mechanisms controlling HEV adhesion was demonstrated by evidence that the thermal induction of ICAM-1 but not of CCL21 involved an interleukin 6 trans-signaling pathway. Our findings identify the 'HEV axis' as a thermally sensitive alert system that heightens immune surveillance during inflammation by amplifying lymphocyte trafficking to lymphoid organs.
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Massberg S, von Andrian UH. Fingolimod and sphingosine-1-phosphate--modifiers of lymphocyte migration. N Engl J Med. 2006;355 (11) :1088-91.
Bonasio R, von Andrian UH. Generation, migration and function of circulating dendritic cells. Curr Opin Immunol. 2006;18 (4) :503-11.Abstract
Tissue-resident dendritic cells (DCs) that migrate from peripheral sites to lymphoid organs are essential in the initiation of adaptive immune responses and for the maintenance of peripheral tolerance, and have been extensively studied. By contrast, blood-borne DCs represent a heterogeneous population, the origin, destination and function of which are still unclear. Recent studies have shown that circulating DCs capture blood-borne antigen and transport it into the extra-vascular space of lymphoid tissues for processing and presentation. Other findings suggest that a fraction of tissue-resident DCs might enter the blood after having acquired antigen in the periphery. Together, these studies imply that circulating DCs might modulate immune responses by translocating antigenic material from its point of origin to remote target tissues.
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Mora RJ, Iwata M, Eksteen B, Song S-Y, Junt T, Senman B, Otipoby KL, Yokota A, Takeuchi H, Ricciardi-Castagnoli P, et al. Generation of gut-homing IgA-secreting B cells by intestinal dendritic cells. Science. 2006;314 (5802) :1157-60.Abstract
Normal intestinal mucosa contains abundant immunoglobulin A (IgA)-secreting cells, which are generated from B cells in gut-associated lymphoid tissues (GALT). We show that dendritic cells (DC) from GALT induce T cell-independent expression of IgA and gut-homing receptors on B cells. GALT-DC-derived retinoic acid (RA) alone conferred gut tropism but could not promote IgA secretion. However, RA potently synergized with GALT-DC-derived interleukin-6 (IL-6) or IL-5 to induce IgA secretion. Consequently, mice deficient in the RA precursor vitamin A lacked IgA-secreting cells in the small intestine. Thus, GALT-DC shape mucosal immunity by modulating B cell migration and effector activity through synergistically acting mediators.
Scimone LM, Aifantis I, Apostolou I, von Boehmer H, von Andrian UH. A multistep adhesion cascade for lymphoid progenitor cell homing to the thymus. Proc Natl Acad Sci U S A. 2006;103 (18) :7006-11.Abstract
Homing of bone marrow (BM)-derived progenitors to the thymus is essential for T cell development. We have previously reported that two subpopulations of common lymphoid progenitors, CLP-1 and CLP-2, coexist in the BM and give rise to lymphocytes. We demonstrate that CLP-2 migrate to the thymus more efficiently than any other BM-derived progenitors. Short-term adoptive transfer experiments revealed that CLP-2 homing involves P-selectin/P-selectin glycoprotein ligand 1 interactions, pertussis toxin-sensitive chemoattractant signaling by CC chemokine ligand 25 through CC chemokine receptor 9, and binding of the integrins alpha4beta1 and alphaLbeta2 to their respective ligands, vascular cell adhesion molecule 1 and intercellular adhesion molecule 1. Preferential thymus-tropism of CLP-2 correlated with higher chemokine receptor 9 expression than on other BM progenitors. Thus, CLP access to the thymus is controlled by a tissue-specific and subset-selective multistep adhesion cascade.
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Mrass P, Takano H, Ng LG, Daxini S, Lasaro MO, Iparraguirre A, Cavanagh LL, von Andrian UH, Ertl HCJ, Haydon PG, et al. Random migration precedes stable target cell interactions of tumor-infiltrating T cells. J Exp Med. 2006;203 (12) :2749-61.Abstract
The tumor microenvironment is composed of an intricate mixture of tumor and host-derived cells that engage in a continuous interplay. T cells are particularly important in this context as they may recognize tumor-associated antigens and induce tumor regression. However, the precise identity of cells targeted by tumor-infiltrating T lymphocytes (TILs) as well as the kinetics and anatomy of TIL-target cell interactions within tumors are incompletely understood. Furthermore, the spatiotemporal conditions of TIL locomotion through the tumor stroma, as a prerequisite for establishing contact with target cells, have not been analyzed. These shortcomings limit the rational design of immunotherapeutic strategies that aim to overcome tumor-immune evasion. We have used two-photon microscopy to determine, in a dynamic manner, the requirements leading to tumor regression by TILs. Key observations were that TILs migrated randomly throughout the tumor microenvironment and that, in the absence of cognate antigen, they were incapable of sustaining active migration. Furthermore, TILs in regressing tumors formed long-lasting (>or=30 min), cognate antigen-dependent contacts with tumor cells. Finally, TILs physically interacted with macrophages, suggesting tumor antigen cross-presentation by these cells. Our results demonstrate that recognition of cognate antigen within tumors is a critical determinant of optimal TIL migration and target cell interactions, and argue against TIL guidance by long-range chemokine gradients.
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Mempel TR, Pittet MJ, Khazaie K, Weninger W, Weissleder R, von Boehmer H, von Andrian UH. Regulatory T cells reversibly suppress cytotoxic T cell function independent of effector differentiation. Immunity. 2006;25 (1) :129-41.Abstract
Mechanisms of dominant tolerance have evolved within the mammalian immune system to prevent inappropriate immune responses. CD4(+)CD25(+) regulatory T (T(reg)) cells have emerged as central constituents of this suppressive activity. By using multiphoton intravital microscopy in lymph nodes (LNs) of anesthetized mice, we have analyzed how cytotoxic T lymphocytes (CTLs) interact with antigen-presenting target cells in the presence or absence of activated T(reg) cells. Nonregulated CTLs killed their targets at a 6.6-fold faster rate than regulated CTLs. In spite of this compromised effector activity, regulated CTLs exhibited no defect in proliferation, induction of cytotoxic effector molecules and secretory granules, in situ motility, or ability to form antigen-dependent conjugates with target cells. Only granule exocytosis by CTLs was markedly impaired in the presence of T(reg) cells. This selective form of regulation did not require prolonged contact between CTLs and T(reg) cells but depended on CTL responsiveness to transforming growth factor-beta. CTLs quickly regained full killing capacity in LNs upon selective removal of T(reg) cells. Thus, T(reg) cells reversibly suppress CTL-mediated immunity by allowing acquisition of full effector potential but withholding the license to kill.
1-s2.0-s1074761306003025-main.pdf sciencedirect_files_06apr2023_17-26-38.419.zip
Krause DS, Lazarides K, von Andrian UH, Van Etten RA. Requirement for CD44 in homing and engraftment of BCR-ABL-expressing leukemic stem cells. Nat Med. 2006;12 (10) :1175-80.Abstract
In individuals with chronic myeloid leukemia (CML) treated by autologous hematopoietic stem cell (HSC) transplantation, malignant progenitors in the graft contribute to leukemic relapse, but the mechanisms of homing and engraftment of leukemic CML stem cells are unknown. Here we show that CD44 expression is increased on mouse stem-progenitor cells expressing BCR-ABL and that CD44 contributes functional E-selectin ligands. In a mouse retroviral transplantation model of CML, BCR-ABL1-transduced progenitors from CD44-mutant donors are defective in homing to recipient marrow, resulting in decreased engraftment and impaired induction of CML-like myeloproliferative disease. By contrast, CD44-deficient stem cells transduced with empty retrovirus engraft as efficiently as do wild-type HSCs. CD44 is dispensable for induction of acute B-lymphoblastic leukemia by BCR-ABL, indicating that CD44 is specifically required on leukemic cells that initiate CML. The requirement for donor CD44 is bypassed by direct intrafemoral injection of BCR-ABL1-transduced CD44-deficient stem cells or by coexpression of human CD44. Antibody to CD44 attenuates induction of CML-like leukemia in recipients. These results show that BCR-ABL-expressing leukemic stem cells depend to a greater extent on CD44 for homing and engraftment than do normal HSCs, and argue that CD44 blockade may be beneficial in autologous transplantation in CML.
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Mempel TR, Junt T, von Andrian UH. Rulers over randomness: stroma cells guide lymphocyte migration in lymph nodes. Immunity. 2006;25 (6) :867-9.Abstract
How is the amoeboid movement of lymphocytes in secondary lymphoid organs orchestrated? In this issue of Immunity, Bajénoff et al. (2006) demonstrate that stromal cell networks serve as guidance structures that direct and limit the migration of B and T cells in lymph nodes.
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Pearce G, Angeli V, Randolph GJ, Junt T, von Andrian U, Schnittler H-J, Jessberger R. Signaling protein SWAP-70 is required for efficient B cell homing to lymphoid organs. Nat Immunol. 2006;7 (8) :827-34.Abstract
The migration of B cells into secondary lymphoid organs is required for the generation of an effective immune response. Here we analyzed the involvement of SWAP-70, a Rac-interacting protein involved in actin rearrangement, in B cell entry into lymph nodes. We noted reduced migration of Swap70-/- B cells into lymph nodes in vivo. Swap70-/- B cells rolled and adhered, yet accumulated in lymph node high endothelial venules. This defect was not due to impaired integrin expression or chemotaxis. Instead, Swap70-/- B cells aberrantly regulated integrin-mediated adhesion. During attachment, Swap70-/- B cells showed defective polarization and did not form uropods or stabilize lamellipodia at a defined region. Thus, SWAP-70 selectively regulates processes essential for B cell entry into lymph nodes.
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Mora RJ, von Andrian UH. Specificity and plasticity of memory lymphocyte migration. Curr Top Microbiol Immunol. 2006;308 :83-116.Abstract
To exert immunological activity, T and B cells must leave the blood and enter different extravascular compartments in the body. An essential step in this process is their adhesion to microvascular endothelium and subsequent diapedesis into a target tissue. Naive and effector/memory T and B cells possess distinct repertoires of traffic molecules that restrict their ability to interact with specialized microvessels in different anatomic compartments and thus exhibit distinct patterns of migration. In addition, antigen-experienced lymphocytes are subdivided into different subsets based on their expression of characteristic sets of adhesion receptors that favor their accumulation in certain target organs, such as the skin and the gut. This article focuses on recent discoveries that have broadened our understanding of the "imprinting" mechanisms responsible for the generation of tissue-specific effector/memory lymphocytes, especially in the intestine. We discuss how gut-specific homing is acquired, maintained, and modulated and how these mechanisms might be harnessed to develop improved vaccine protocols and treatments for intestinal autoimmune diseases.
O'Leary JG, Goodarzi M, Drayton DL, von Andrian UH. T cell- and B cell-independent adaptive immunity mediated by natural killer cells. Nat Immunol. 2006;7 (5) :507-16.Abstract
It is commonly believed that only T lymphocytes and B lymphocytes expressing recombination-dependent antigen-specific receptors mediate contact hypersensitivity responses to haptens. Here we found that mice devoid of T cells and B cells demonstrated substantial contact hypersensitivity responses to 2,4-dinitrofluorobenzene and oxazolone. Those responses were adaptive in nature, as they persisted for at least 4 weeks and were elicited only by haptens to which mice were previously sensitized. No contact hypersensitivity was induced in mice lacking all lymphocytes, including natural killer cells. Contact hypersensitivity responses were acquired by such mice after adoptive transfer of natural killer cells from sensitized donors. Transferable hapten-specific memory resided in a Ly49C-I(+) natural killer subpopulation localized specifically in donor livers. These observations indicate that natural killer cells can mediate long-lived, antigen-specific adaptive recall responses independent of B cells and T cells.
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Mora RJ, von Andrian UH. T-cell homing specificity and plasticity: new concepts and future challenges. Trends Immunol. 2006;27 (5) :235-43.Abstract
Naive and effector/memory T cells have distinct repertoires of trafficking ligands and receptors that restrict their ability to interact with specialized microvessels in different anatomical compartments and, consequently, have distinct patterns of migration. Antigen-experienced lymphocytes can be further subdivided into different subsets based on their expression of characteristic sets of trafficking receptors that favor their accumulation in certain target organs, including the skin and gut. Here, we summarize recent advances that have broadened our understanding of the cellular and molecular events that induce the generation of tissue-specific effector/memory T cells and discuss how these mechanisms could be harnessed for the therapeutic manipulation of T-cell-dependent pathologies.
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Wang J, Fathman JW, Lugo-Villarino G, Scimone L, von Andrian U, Dorfman DM, Glimcher LH. Transcription factor T-bet regulates inflammatory arthritis through its function in dendritic cells. J Clin Invest. 2006;116 (2) :414-21.Abstract
The transcription factor T-bet (Tbx21) plays a major role in adaptive immunity and is required for optimal IFN-gamma production by DCs. Here we demonstrate an essential function for T-bet in DCs in controlling inflammatory arthritis. We show that collagen antibody-induced arthritis (CAIA), a model of human RA, is a bipartite disease characterized by an early innate immune system component intact in RAG2 mice and a later adaptive immune system phase. Mice lacking T-bet had markedly reduced joint inflammation at both early and late time points and RAG2T-bet double-deficient mice were essentially resistant to disease. Remarkably, adoptive transfer of T-bet-expressing DCs reconstituted inflammation in a T-bet deficient and T-bet/RAG2-deficient milieu. T-bet regulates the production of proinflammatory cytokine IL-1alpha and chemokines macrophage inflammatory protein-1alpha (MIP-1alpha) and thymus- and activation-related chemokine (TARC) by DCs. Further, T-bet expression in DCs is required for T helper cell activation. We conclude that T-bet plays a vital function in DCs that links innate and adaptive immunity to regulate inflammatory responses. T-bet provides an attractive new target for the development of novel therapeutics for inflammatory arthritis.