Friend retrovirus infection of myeloid dendritic cells impairs maturation, prolongs contact to naïve T cells, and favors expansion of regulatory T cells

Blood ◽  
2007 ◽  
Vol 110 (12) ◽  
pp. 3949-3958 ◽  
Author(s):  
Sandra Balkow ◽  
Frank Krux ◽  
Karin Loser ◽  
Jan U. Becker ◽  
Stephan Grabbe ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Regulatory T Cells ◽  
Immune Escape ◽  
Cell Contact ◽  
Myeloid Dendritic Cells ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Friend Retrovirus

Abstract Retroviruses have developed immunmodulatory mechanisms to avoid being attacked by the immune system. The mechanisms of this retrovirus-associated immune suppression are far from clarified. Dendritic cells (DCs) have been attributed a decisive role in these pathogenic processes. We have used the Friend retrovirus (FV) mouse model in order to acquire further knowledge about the role of infection of DCs in virus-induced immunosuppression. About 20% of the myeloid DCs that were generated from the bone marrow of FV-infected mice carried FV proteins. The infection was productive, and infected DCs transmitted the virus in cell culture and in vivo. FV infection of DCs led to a defect in DC maturation, as infected cells expressed very little costimulatory molecules. Live imaging analysis of the cell contact between DCs and T cells revealed prolonged contacts of T cells with infected DCs compared with uninfected DCs. Although naive T cells were still activated by FV-infected DCs, this activation did not result in antigen-specific T-cell proliferation. Interestingly, infected DCs expanded a population of Foxp3+ regulatory T cells with immunosuppressive potential, suggesting that the contact between naive T cells and retrovirus-infected DCs results in tolerance rather than immunity. Thus, retroviral infection of DCs leads to an expansion of regulatory T cells, which might serve as an immune escape mechanism of the virus.

scholarly journals Expansion of FOXP3high regulatory T cells by human dendritic cells (DCs) in vitro and after injection of cytokine-matured DCs in myeloma patients

Blood ◽  
2006 ◽  
Vol 108 (8) ◽  
pp. 2655-2661 ◽  
Author(s):  
Devi K. Banerjee ◽  
Madhav V. Dhodapkar ◽  
Elyana Matayeva ◽  
Ralph M. Steinman ◽  
Kavita M. Dhodapkar
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Regulatory T Cells ◽  
Interleukin 2 ◽  
Cell Contact ◽  
Myeloid Dendritic Cells ◽  
Healthy Donors

AbstractCD4+CD25+FOXP3+ regulatory T cells (Treg's) play an important role in the maintenance of immune tolerance. The mechanisms controlling the induction and maintenance of Treg's in humans need to be defined. We find that human myeloid dendritic cells (DCs) are superior to other antigen presenting cells for the maintenance of FOXP3+ Treg's in culture. Coculture of DCs with autologous T cells leads to an increase in both the number of Treg's, as well as the expression of FOXP3 protein per cell both in healthy donors and myeloma patients. DC-mediated expansion of FOXP3high Treg's is enhanced by endogenous but not exogenous interleukin-2 (IL-2), and DC-T-cell contact, including the CD80/CD86 membrane costimulatory molecules. DCs also stimulate the formation of Treg's from CD25- T cells. The efficacy of induction of Treg's by DCs depends on the nature of the DC maturation stimulus, with inflammatory cytokine-treated DCs (Cyt-DCs) being the most effective Treg inducers. DC-induced Treg's from both healthy donors and patients with myeloma are functional and effectively suppress T-cell responses. A single injection of cytokine-matured DCs led to rapid enhancement of FOXP3+ Treg's in vivo in 3 of 3 myeloma patients. These data reveal a role for DCs in increasing the number of functional FOXP3high Treg's in humans.

Steady-state dendritic cells expressing cognate antigen terminate memory CD8+ T-cell responses

Blood ◽  
2008 ◽  
Vol 111 (4) ◽  
pp. 2091-2100 ◽  
Author(s):  
Tony J. Kenna ◽  
Ranjeny Thomas ◽  
Raymond J. Steptoe
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Steady State ◽  
T Cell ◽  
Developmental Plasticity ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Cognate Antigen ◽  
Costimulatory Signals

Antigen stimulation of naive T cells in conjunction with strong costimulatory signals elicits the generation of effector and memory populations. Such terminal differentiation transforms naive T cells capable of differentiating along several terminal pathways in response to pertinent environmental cues into cells that have lost developmental plasticity and exhibit heightened responsiveness. Because these cells exhibit little or no need for the strong costimulatory signals required for full activation of naive T cells, it is generally considered memory and effector T cells are released from the capacity to be inactivated. Here, we show that steady-state dendritic cells constitutively presenting an endogenously expressed antigen inactivate fully differentiated memory and effector CD8+ T cells in vivo through deletion and inactivation. These findings indicate that fully differentiated effector and memory T cells exhibit a previously unappreciated level of plasticity and provide insight into how memory and effector T-cell populations may be regulated.

Naive B cells generate regulatory T cells in the presence of a mature immunologic synapse

Blood ◽  
2007 ◽  
Vol 110 (5) ◽  
pp. 1519-1529 ◽  
Author(s):  
Peter Reichardt ◽  
Bastian Dornbach ◽  
Song Rong ◽  
Stefan Beissert ◽  
Faikah Gueler ◽  
...  
Keyword(s):  
T Cells ◽  
B Cells ◽  
Regulatory T Cells ◽  
Immune Responses ◽  
B Cell ◽  
Dependent Manner ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Immunologic Synapse

Abstract Naive B cells are ineffective antigen-presenting cells and are considered unable to activate naive T cells. However, antigen-specific contact of these cells leads to stable cell pairs that remain associated over hours in vivo. The physiologic role of such pairs has not been evaluated. We show here that antigen-specific conjugates between naive B cells and naive T cells display a mature immunologic synapse in the contact zone that is absent in T-cell–dendritic-cell (DC) pairs. B cells induce substantial proliferation but, contrary to DCs, no loss of L-selectin in T cells. Surprisingly, while DC-triggered T cells develop into normal effector cells, B-cell stimulation over 72 hours induces regulatory T cells inhibiting priming of fresh T cells in a contact-dependent manner in vitro. In vivo, the regulatory T cells home to lymph nodes where they potently suppress immune responses such as in cutaneous hypersensitivity and ectopic allogeneic heart transplant rejection. Our finding might help to explain old observations on tolerance induction by B cells, identify the mature immunologic synapse as a central functional module of this process, and suggest the use of naive B-cell–primed regulatory T cells, “bTregs,” as a useful approach for therapeutic intervention in adverse adaptive immune responses.

scholarly journals Smad3 binding to the foxp3 enhancer is dispensable for the development of regulatory T cells with the exception of the gut

2012 ◽  
Vol 209 (9) ◽  
pp. 1529-1535 ◽  
Author(s):  
Susan M. Schlenner ◽  
Benno Weigmann ◽  
Qingguo Ruan ◽  
Youhai Chen ◽  
Harald von Boehmer
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Transcription Initiation ◽  
Foxp3 Expression ◽  
Cell Development ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Smad3 Binding

Regulatory T cells (T reg cells) are essential for the prevention of autoimmunity throughout life. T reg cell development occurs intrathymically but a subset of T reg cells can also differentiate from naive T cells in the periphery. In vitro, Smad signaling facilitates conversion of naive T cells into T reg cells but results in unstable Foxp3 expression. The TGF-β–Smad response element in the foxp3 locus is located in the CNS1 region in close proximity to binding sites for transcription factors implicated in TCR and retinoic acid signaling. From in vitro experiments it was previously postulated that foxp3 transcription represents a hierarchical process of transcription factor binding in which Smad3 would play a central role in transcription initiation. However, in vitro conditions generate T reg cells that differ from T reg cells encountered in vivo. To address the relevance of Smad3 binding to the CNS1 enhancer in vivo, we generated mice that exclusively lack the Smad binding site (foxp3CNS1mut). We show that binding of Smad3 to the foxp3 enhancer is dispensable for T reg cell development in newborn and adult mice with the exception of the gut.

Human CD4+ CD25high Regulatory T Cells Inhibit Myeloid but Not Plasmacytoid Dendritic Cells Activation.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 767-767
Author(s):  
Roch Houot ◽  
Ivan Perrot ◽  
Isabelle Durand ◽  
Eric Garcia ◽  
Serge Lebecque
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Regulatory T Cells ◽  
Inflammatory Cytokines ◽  
Human Peripheral Blood ◽  
Cell Contact ◽  
Cytokines Secretion ◽  
Pro Inflammatory Cytokines

Abstract CD4+CD25+ regulatory T cells (Treg) are essential negative regulators of immune responses. However, the mechanisms of immune suppression and the spectrum of cells they target remain incompletely defined. In particular, although Treg directly suppress conventional T cells in vitro, they might also affect antigen presenting cells (APC). Here, we studied the maturation of human myeloid (mDC) and plasmacytoid (pDC) dendritic cells activated with Toll-like receptor (TLR) ligands in the presence of CD4+ CD25high regulatory T cells in vitro. T cells and DC subsets were purified from normal human peripheral blood. LPS, CpG ODN 2216 and R-848 were used to trigger the maturation of mDC, pDC or both through TLR4, TLR9 and TLR7/8 respectively. Preactivated CD4+ CD25high Treg had no effect on the maturation of pDC. Conversely, they strongly suppressed TLR-triggered mDC costimulatory molecules up-regulation, pro-inflammatory cytokines secretion and their antigen presentation capacity, as opposed to conventionnal T cells (Tconv). At a ratio of 3 Treg for 1 DC, the percentage of mDC acquiring CD80 was reduced 5 fold (from 75% to 16%) while the Mean Fluorescence Intensity was decreased by approximately 65% for CD80 and 35% for CD86 after LPS stimulation and by 50% and 20% after R-848 stimulation. Furthermore, Treg dramatically decreased the secretion of IL-12p40, TNF-α, and IL-6 by mDC (95%, 93% and 50% average inhibition respectively) after LPS activation and to a lesser but still significant extent (38%, 35%, and 38% average inhibition respectively) after R848 stimulation. Finally, we found that Treg-conditionned mDC had a reduced ability to trigger naïve T cell proliferation in a mixed leukocyte reaction. Suppression of mDC activation by Treg appeared to require cell-cell contact. Moreover, the inhibition of pro-inflammatory cytokines secretion, but not of phenotypic maturation, was almost completely restored using an anti-IL10 receptor monoclonal antibody, but not anti-TGFβ nor anti-CTLA-4 blocking antibodies. Those data suggest that Treg prevent the co-stimulatory molecules up-regulation on mDC through contact dependent mechanisms, while the modulation of cytokines secretion appears to be largely mediated by IL-10. Overall, our results provide the first evidence of a direct inhibition of human mDC but not pDC maturation by CD4+ CD25high Treg. Therefore, by restraining the maturation of mDC, human Treg may enlist those cells for the initiation and the amplification of tolerance in vivo.

scholarly journals Killing of naive T cells by CD95L-transfected dendritic cells (DC):in vivo study using killer DC-DC hybrids and CD4+ T cells from DO11.10 mice

2002 ◽  
Vol 32 (4) ◽  
pp. 1035-1043 ◽  
Author(s):  
Masahiro Kusuhara ◽  
Keiko Matsue ◽  
Dale Edelbaum ◽  
Julie Loftus ◽  
Akira Takashima ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Cd4 T Cells ◽  
In Vivo Study ◽  
Naive T Cells ◽  
Naïve T Cells

scholarly journals CD8α+ and CD8α− Subclasses of Dendritic Cells Direct the Development of Distinct T Helper Cells In Vivo

1999 ◽  
Vol 189 (3) ◽  
pp. 587-592 ◽  
Author(s):  
Roberto Maldonado-López ◽  
Thibaut De Smedt ◽  
Patrick Michel ◽  
Jacques Godfroid ◽  
Bernard Pajak ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Critical Role ◽  
Interleukin 12 ◽  
T Helper ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Physiologic Function

Cells of the dendritic family display some unique properties that confer to them the capacity to sensitize naive T cells in vitro and in vivo. In the mouse, two subclasses of dendritic cells (DCs) have been described that differ by their CD8α expression and their localization in lymphoid organs. The physiologic function of both cell populations remains obscure. Studies conducted in vitro have suggested that CD8α+ DCs could play a role in the regulation of immune responses, whereas conventional CD8α− DCs would be more stimulatory. We report here that both subclasses of DCs efficiently prime antigen-specific T cells in vivo, and direct the development of distinct T helper (Th) populations. Antigen-pulsed CD8α+ and CD8α− DCs are separated after overnight culture in recombinant granulocyte/macrophage colony-stimulating factor and injected into the footpads of syngeneic mice. Administration of CD8α− DCs induces a Th2-type response, whereas injection of CD8α+ DCs leads to Th1 differentiation. We further show that interleukin 12 plays a critical role in Th1 development by CD8α+ DCs. These findings suggest that the nature of the DC that presents the antigen to naive T cells may dictate the class selection of the adaptative immune response.

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