scholarly journals Role for Dendritic Cells in Immunoregulation during Experimental Vaginal Candidiasis

2006 ◽  
Vol 74 (6) ◽  
pp. 3213-3221 ◽  
Author(s):  
Dana M. LeBlanc ◽  
Melissa M. Barousse ◽  
Paul L. Fidel

ABSTRACT Vulvovaginal candidiasis (VVC) caused by the commensal organism Candida albicans remains a significant problem among women of childbearing age, with protection against and susceptibility to infection still poorly understood. While cell-mediated immunity by CD4+ Th1-type cells is protective against most forms of mucosal candidiasis, no protective role for adaptive immunity has been identified against VVC. This is postulated to be due to immunoregulation that prohibits a more profound Candida-specific CD4+ T-cell response against infection. The purpose of this study was to examine the role of dendritic cells (DCs) in the induction phase of the immune response as a means to understand the initiation of the immunoregulatory events. Immunostaining of DCs in sectioned murine lymph nodes draining the vagina revealed a profound cellular reorganization with DCs becoming concentrated in the T-cell zone throughout the course of experimental vaginal Candida infection consistent with cell-mediated immune responsiveness. However, analysis of draining lymph node DC subsets revealed a predominance of immunoregulation-associated CD11c+ B220+ plasmacytoid DCs (pDCs) under both uninfected and infected conditions. Staining of vaginal DCs showed the presence of both DEC-205+ and pDCs, with extension of dendrites into the vaginal lumen of infected mice in close contact with Candida. Flow cytometric analysis of draining lymph node DC costimulatory molecules and activation markers from infected mice indicated a lack of upregulation of major histocompatibility complex class II, CD80, CD86, and CD40 during infection, consistent with a tolerizing condition. Together, the results suggest that DCs are involved in the immunoregulatory events manifested during a vaginal Candida infection and potentially through the action of pDCs.

1983 ◽  
Vol 157 (5) ◽  
pp. 1448-1460 ◽  
Author(s):  
C D Mills ◽  
R J North

The results of this study with the P815 mastocytoma confirm the results of previous studies that showed that the passive transfer of tumor-sensitized T cells from immunized donors can cause the regression of tumors growing in T cell-deficient (TXB) recipients, but not in normal recipients. The key additional finding was that the expression of adoptive immunity against tumors growing in TXB recipients is immediately preceded by a substantial production of cytolytic T cells in the recipients' draining lymph node. On the other hand, failure of adoptive immunity to be expressed against tumors growing in normal recipients was associated with a cytolytic T cell response of much lower magnitude, and a similar low magnitude response was generated in TXB recipients infused with normal spleen cells and in tumor-bearing control mice. Because the passively transferred sensitized T cells possessed no cytolytic activity of their own, the results indicate that the 6-8-d delay before adoptive immunity is expressed represents the time needed for passively transferred helper or memory T cells to give rise to a cytolytic T cell response of sufficient magnitude to destroy the recipient's tumor. In support of this interpretation was the additional finding that inhibition of the expression of adoptive immunity by the passive transfer of suppressor T cells from tumor-bearing donors was associated with a substantially reduced cytolytic T cell response in the recipient's draining lymph node. The results serve to illustrate that interpretation of the results of adoptive immunization experiments requires a knowledge of the events that take place in the adoptively immunized recipient. They support the interpretation that suppressor T cells function in this model to "down-regulate" the production of cytolytic effector T cells.


2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Jillian P Rhoads ◽  
Ashley J Wilhelm ◽  
Amy S Major

Antibodies to oxidized LDL (oxLDL) and resulting immune complexes (ICs) are a prominent feature of atherosclerosis and diseases associated with increased atherosclerosis including Type 2-diabetes and rheumatoid arthritis. Although levels of oxLDL-ICs correlate with disease severity and associate with pro-inflammatory activation of macrophages in vitro , it is currently unclear whether these ICs are simply biomarkers or play an active role in disease pathogenesis. One possible mechanism by which oxLDL-ICs may regulate inflammation in atherosclerosis is by interacting with Fc gamma receptors (FcgRs) expressed on the surface of antigen presenting cells, such as dendritic cells (DCs). Not surprisingly, signaling through FcgRs is tightly regulated and dependent on their relative cell surface density. In addition, FcgR signaling has been shown to be linked to Toll like receptor-4 (TLR-4), a pattern recognition receptor. We hypothesize that oxLDL-ICs exacerbate atherosclerosis via signaling through FcgRs and TLR4 on DCs resulting in a pro-inflammatory T cell response. To test this hypothesis, bone marrow derived DCs (BMDCs) were treated with in vitro generated oxLDL ICs. Interestingly, BMDCs treated with oxLDL-ICs had increased expression of the activation markers MHC-II and CD40 and produced greater levels of the Th17 polarizing cytokines IL-1beta and IL-23 compared to cells treated with oxLDL alone. Secretion of pro-inflammatory cytokines was significantly decreased by pre-treatment of BMDCs with a TLR4 inhibitor and by blocking FcgR signaling. This suggests that responses to oxLDL-ICs involve both TLR-4 and FcgRs. Furthermore, incubation of OT-II T cells with BMDCs treated with oxLDL-IC prior to incubation with ovalbumin peptide displayed increased pro-inflammatory cytokine secretion compared to incubation with oxLDL alone. In conclusion, our studies provide new evidence that oxLDL-ICs signal through multiple receptors on DCs resulting in increased inflammatory potential. Because of their critical function in shaping the T cell response, we believe that DC signaling via FcgRs and oxLDL-ICs represents an important link between innate and adaptive immunity in atherosclerosis.


2003 ◽  
Vol 198 (4) ◽  
pp. 615-621 ◽  
Author(s):  
Alfonso Martín-Fontecha ◽  
Silvia Sebastiani ◽  
Uta E. Höpken ◽  
Mariagrazia Uguccioni ◽  
Martin Lipp ◽  
...  

Antigen-pulsed dendritic cells (DCs) are used as natural adjuvants for vaccination, but the factors that influence the efficacy of this treatment are poorly understood. We investigated the parameters that affect the migration of subcutaneously injected mouse-mature DCs to the draining lymph node. We found that the efficiency of DC migration varied with the number of injected DCs and that CCR7+/+ DCs migrating to the draining lymph node, but not CCR7−/− DCs that failed to do so, efficiently induced a rapid increase in lymph node cellularity, which was observed before the onset of T cell proliferation. We also report that DC migration could be increased up to 10-fold by preinjection of inflammatory cytokines that increased the expression of the CCR7 ligand CCL21 in lymphatic endothelial cells. The magnitude and quality of CD4+ T cell response was proportional to the number of antigen-carrying DCs that reached the lymph node and could be boosted up to 40-fold by preinjection of tumor necrosis factor that conditioned the tissue for increased DC migration. These results indicate that DC number and tissue inflammation are critical parameters for DC-based vaccination.


2017 ◽  
Author(s):  
David E. Place ◽  
David R. Williamson ◽  
Yevgeniy Yuzefpolskiy ◽  
Bhuvana Katkere ◽  
Surojit Sarkar ◽  
...  

ABSTRACTProgress towards a safe and effective vaccine for the prevention of tularemia has been hindered by a lack of knowledge regarding the correlates of protective adaptive immunity and a lack of tools to generate this knowledge. CD8+T cells are essential for protective immunity against virulent strains ofFrancisella tularensis, but to-date, it has not been possible to study these cells in a pathogen-specific manner. Here, we report the development of a tool for expression of the model antigen ovalbumin (OVA) inF. tularensis, which allows for the study of CD8+T cell responses to the bacterium. We demonstrate that in response to intranasal infection with theF. tularensisLive Vaccine Strain, pathogen-specific CD8+T cells expand after the first week and produce IFN-γ but not IL-17. Effector and central memory subsets develop with disparate kinetics in the lungs, draining lymph node and spleen. Notably,F. tularensis-specific cells are poorly retained in the lungs after clearance of infection. We also show that intranasal vaccination leads to more pathogen-specific CD8+T cells in the lung-draining lymph node compared to scarification vaccination, but that an intranasal booster overcomes this difference. Together, our data show that this novel tool can be used to study multiple aspects of the CD8+T cell response toF. tularensis. Use of this tool will enhance our understanding of immunity to this deadly pathogen.


2021 ◽  
Vol 11 ◽  
Author(s):  
Cedric Bosteels ◽  
Kaat Fierens ◽  
Sofie De Prijck ◽  
Justine Van Moorleghem ◽  
Manon Vanheerswynghels ◽  
...  

The Adjuvant System AS01 contains monophosphoryl lipid A (MPL) and the saponin QS-21 in a liposomal formulation. AS01 is included in recently developed vaccines against malaria and varicella zoster virus. Like for many other adjuvants, induction of adaptive immunity by AS01 is highly dependent on the ability to recruit and activate dendritic cells (DCs) that migrate to the draining lymph node for T and B cell stimulation. The objective of this study was to more precisely address the contribution of the different conventional (cDC) and monocyte-derived DC (MC) subsets in the orchestration of the adaptive immune response after immunization with AS01 adjuvanted vaccine. The combination of MPL and QS-21 in AS01 induced strong recruitment of CD26+XCR1+ cDC1s, CD26+CD172+ cDC2s and a recently defined CCR2-dependent CD64-expressing inflammatory cDC2 (inf-cDC2) subset to the draining lymph node compared to antigen alone, while CD26-CD64+CD88+ MCs were barely detectable. At 24 h post-vaccination, cDC2s and inf-cDC2s were superior amongst the different subsets in priming antigen-specific CD4+ T cells, while simultaneously presenting antigen to CD8+ T cells. Diphtheria toxin (DT) mediated depletion of all DCs prior to vaccination completely abolished adaptive immune responses, while depletion 24 h after vaccination mainly affected CD8+ T cell responses. Vaccinated mice lacking Flt3 or the chemokine receptor CCR2 showed a marked deficit in inf-cDC2 recruitment and failed to raise proper antibody and T cell responses. Thus, the adjuvant activity of AS01 is associated with the potent activation of subsets of cDC2s, including the newly described inf-cDC2s.


2015 ◽  
Vol 11 (10) ◽  
pp. e1005206 ◽  
Author(s):  
Vishnu Priya Bollampalli ◽  
Lívia Harumi Yamashiro ◽  
Xiaogang Feng ◽  
Damiën Bierschenk ◽  
Yu Gao ◽  
...  

1999 ◽  
Vol 189 (3) ◽  
pp. 593-598 ◽  
Author(s):  
Adrian L. Smith ◽  
Barbara Fazekas de St. Groth

Two subsets of murine splenic dendritic cells, derived from distinct precursors, can be distinguished by surface expression of CD8α homodimers. The functions of the two subsets remain controversial, although it has been suggested that the lymphoid-derived (CD8α+) subset induces tolerance, whereas the myeloid-derived (CD8α−) subset has been shown to prime naive T cells and to generate memory responses. To study their capacity to prime or tolerize naive CD4+ T cells in vivo, purified CD8α+ or CD8α− dendritic cells were injected subcutaneously into normal mice. In contrast to CD8α− dendritic cells, the CD8α+ fraction failed to traffic to the draining lymph node and did not generate responses to intravenous peptide. However, after in vitro pulsing with peptide, strong in vivo T cell responses to purified CD8α+ dendritic cells could be detected. Such responses may have been initiated via transfer of peptide–major histocompatibility complex complexes to migratory host CD8α− dendritic cells after injection. These data suggest that correlation of T helper cell type 1 (Th1) and Th2 priming with injection of CD8α+ and CD8α− dendritic cells, respectively, may not result from direct T cell activation by lymphoid versus myeloid dendritic cells, but rather from indirect modification of the response to immunogenic CD8α− dendritic cells by CD8α+ dendritic cells.


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