F.38. Kinetics of Dendritic Cells Reconstitution and Costimulatory Molecules Expression After...
1
N 1/10,000. Thus the sensitivity for NMO was 88%. There was high concordance with established detection assays. The reactivity appeared to be predominantly of the IgG1 isotype and was restricted to native epitopes as probing of blotted cell lysates by NMO sera was negative. This novel assay is highly sensitive and specific for NMO. It is easy to use and allows for high-throughput screening. The restricted im- mune response against native epitopes warrants further exploration. doi:10.1016/j.clim.2008.03.148 F.37. Retinoic Acid Increases Foxp3+ Regulatory T Cells and Inhibits Development of Th17 Cells by Enhancing TGF-b-driven Smad3 Signaling and Inhibiting IL-6 and IL-23 Receptor Expression Sheng Xiao, 1 Hulin Jin, 2 Sue Liu, 1 Thomas Korn, 1 Mohamed Oukka, 1 Bing Lim, 2 Vijay Kuchroo. 11 Brigham and Women's Hospital and Harvard Medical School, Boston, MA; 2 Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA The de novo generation of Foxp3+ regulatory T (Treg) cells in the peripheral immune compartment and the differentiation of Th17 cells both require TGF-b, and IL-6 and IL-21 are switch factors that drive the development of Th17 cells at the expense of Treg generation. The major vitamin A metabolite all-trans retinoic acid (RA) not only enforces the generation of Treg but also inhibits the differentiation of Th17 cells. Here we show that RA enhances TGF-b signaling by increasing the expression and posphorylation of Smad3 and this results in increased Foxp3 expression even in the presence of IL-6 or IL-21. However, RA also inhibits the expression of IL-6Ra, IRF-4 and IL-23R and thus inhibits Th17 differentiation. Although RA decreases expression of IL-17 and IL-23R, it has minimal effect on the RORgt expression. In vitro, RA significantly promotes Treg conversion but in vivo during the develop- ment of experimental autoimmune encephalomyelitis it does not increase the frequency of Treg cells. However, RA suppresses the disease very efficiently by decreasing proinflammatory T cell responses, especially pathogenic Th17 responses. These data identify the signaling mechan- isms by which RA can affect both Treg and Th17 differentiation but also highlight that in vivo during an autoimmune reaction, RA suppresses autoimmunity mainly by inhibiting the generation of effector Th17 cells. doi:10.1016/j.clim.2008.03.149 Bone Marrow or Stem Cell Transplantation F.38. Kinetics of Dendritic Cells Reconstitution and Costimulatory Molecules Expression After Myeloablative Allogeneic Haematopoetic Stem Cell Transplantation: Implications for the Development of Acute Graft-versus-host Disease Rudolf Horvath, Vit Budinsky, Jana Kayserova, Renata Formankova, Tomas Kalina, Jan Stary, Petr Sedlacek, Jirina Bartunkova, Radek Spisek. Charles University, 2nd Medical School and Faculty Hospital Motol, Prague, Czech Republic Allogeneic hematopoetic stem cell transplantation (allo-HSCT) with myeloablative conditioning represents a unique opportunity to monitor the kinetics of hematopoe- tic cells reconstitution. Dendritic cells (DCs) are the most efficient antigen presenting cells. Two distinct subsets of DCs have been identified - myeloid (mDCs) and plasmacy- toid (pDCs) that have different roles in the regulation of immunity. In this study, we analyzed the kinetics of DCs subsets reconstitution in 13 pediatric patients undergoing allo-HSCT. Myeloid DCs were defined as lineage -, CD11c+, HLA-DR+ and pDCs as lineage -, CD123+ and HLA-DR+. We further evaluated activation status of circulating DCs by simultaneous monitoring of costimulatory molecules expression (CD80, CD83 and CD86). Peripheral blood DCs were monitored from the earliest phase of hematopoetic reconstitution until day 365 after HSCT. Both mDCs and pDCs appeared at earliest stages after engraftment and relative numbers within white blood cells compartment peaked between days 19-25 after HSCT. Their proportion then gradually declined and absolute levels of both DCs subsets remained lower for the whole follow-up period when compared to controls. Expression of costimulatory molecules, especially CD83 and CD86 transiently increased between days 15 and 35 and then went back to low steady state levels. Interestingly, patients who developed acute graft-versus-host disease (aGVHD) had significantly lower numbers of circulating DCs. Detailed analysis of DCs in patients with aGVHD revealed that the decline in DCs counts preceded development of clinical symptoms by at least 24 h. This study provides further inside into the biology of DCs in the settings of allo-HSCT and reveals quantification of DCs counts as potential biomarker for the prediction of aGVHD development. doi:10.1016/j.clim.2008.03.150 F.39. Alloimmunogenicity of Pericytes Isolated from Human Placenta Cheryl Maier, Benjamin Shepherd, Jordan Pober. Yale University School of Medicine, New Haven, CT Microvascular pericytes are contractile stromal cells that stabilize blood capillaries and have great potential for use in tissue engineering. Other stromal cell types, like mesench- ymal stem cells (MSC) and smooth muscle cells (SMC), reportedly inhibit T lymphocyte responses. Here we inves- tigate the immunologic functions of microvascular pericytes (PC) isolated from human placenta, comparing these cells to human umbilical vein endothelial cells (EC), to human aortic SMC and to human bone marrow-derived MSC. PC were isolated and cultured by explant outgrowth from collage- nase-digested placental microvessel fragments in M199 medium containing 20% fetal calf serum on tissue culture plastic. Cultured PC are spindle-like with prominent actin filaments and retract to form postconfluent multicellular S55 Abstracts
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Transcript of F.38. Kinetics of Dendritic Cells Reconstitution and Costimulatory Molecules Expression After...
N1/10,000. Thus the sensitivity for NMO was 88%. There washigh concordance with established detection assays. Thereactivity appeared to be predominantly of the IgG1 isotypeand was restricted to native epitopes as probing of blottedcell lysates by NMO sera was negative. This novel assay ishighly sensitive and specific for NMO. It is easy to use andallows for high-throughput screening. The restricted im-mune response against native epitopes warrants furtherexploration.
doi:10.1016/j.clim.2008.03.148
F.37. Retinoic Acid Increases Foxp3+ Regulatory TCells and Inhibits Development of Th17 Cells byEnhancing TGF-b-driven Smad3 Signaling andInhibiting IL-6 and IL-23 Receptor ExpressionSheng Xiao,1 Hulin Jin,2 Sue Liu,1 Thomas Korn,1 MohamedOukka,1 Bing Lim,2 Vijay Kuchroo.1 1Brigham and Women'sHospital and Harvard Medical School, Boston, MA; 2BethIsrael Deaconess Medical Center and Harvard MedicalSchool, Boston, MA
The de novo generation of Foxp3+ regulatory T (Treg)cells in the peripheral immune compartment and thedifferentiation of Th17 cells both require TGF-b, and IL-6and IL-21 are switch factors that drive the development ofTh17 cells at the expense of Treg generation. The majorvitamin A metabolite all-trans retinoic acid (RA) not onlyenforces the generation of Treg but also inhibits thedifferentiation of Th17 cells. Here we show that RAenhances TGF-b signaling by increasing the expressionand posphorylation of Smad3 and this results in increasedFoxp3 expression even in the presence of IL-6 or IL-21.However, RA also inhibits the expression of IL-6Ra, IRF-4and IL-23R and thus inhibits Th17 differentiation. AlthoughRA decreases expression of IL-17 and IL-23R, it has minimaleffect on the RORgt expression. In vitro, RA significantlypromotes Treg conversion but in vivo during the develop-ment of experimental autoimmune encephalomyelitis itdoes not increase the frequency of Treg cells. However, RAsuppresses the disease very efficiently by decreasingproinflammatory T cell responses, especially pathogenicTh17 responses. These data identify the signaling mechan-isms by which RA can affect both Treg and Th17differentiation but also highlight that in vivo during anautoimmune reaction, RA suppresses autoimmunity mainlyby inhibiting the generation of effector Th17 cells.
doi:10.1016/j.clim.2008.03.149
Bone Marrow or Stem Cell Transplantation
F.38. Kinetics of Dendritic Cells Reconstitutionand Costimulatory Molecules Expression AfterMyeloablative Allogeneic HaematopoeticStem Cell Transplantation: Implicationsfor the Development of AcuteGraft-versus-host Disease
Rudolf Horvath, Vit Budinsky, Jana Kayserova, RenataFormankova, Tomas Kalina, Jan Stary, Petr Sedlacek, JirinaBartunkova, Radek Spisek. Charles University, 2nd MedicalSchool and Faculty Hospital Motol, Prague, Czech Republic
Allogeneic hematopoetic stem cell transplantation(allo-HSCT) with myeloablative conditioning represents aunique opportunity to monitor the kinetics of hematopoe-tic cells reconstitution. Dendritic cells (DCs) are the mostefficient antigen presenting cells. Two distinct subsets ofDCs have been identified - myeloid (mDCs) and plasmacy-toid (pDCs) that have different roles in the regulation ofimmunity. In this study, we analyzed the kinetics of DCssubsets reconstitution in 13 pediatric patients undergoingallo-HSCT. Myeloid DCs were defined as lineage -, CD11c+,HLA-DR+ and pDCs as lineage -, CD123+ and HLA-DR+. Wefurther evaluated activation status of circulating DCs bysimultaneous monitoring of costimulatory moleculesexpression (CD80, CD83 and CD86). Peripheral blood DCswere monitored from the earliest phase of hematopoeticreconstitution until day 365 after HSCT. Both mDCs andpDCs appeared at earliest stages after engraftment andrelative numbers within white blood cells compartmentpeaked between days 19-25 after HSCT. Their proportionthen gradually declined and absolute levels of both DCssubsets remained lower for the whole follow-up periodwhen compared to controls. Expression of costimulatorymolecules, especially CD83 and CD86 transiently increasedbetween days 15 and 35 and then went back to low steadystate levels. Interestingly, patients who developed acutegraft-versus-host disease (aGVHD) had significantly lowernumbers of circulating DCs. Detailed analysis of DCs inpatients with aGVHD revealed that the decline in DCscounts preceded development of clinical symptoms by atleast 24 h. This study provides further inside into thebiology of DCs in the settings of allo-HSCT and revealsquantification of DCs counts as potential biomarker for theprediction of aGVHD development.
doi:10.1016/j.clim.2008.03.150
F.39. Alloimmunogenicity of Pericytes Isolated fromHuman PlacentaCheryl Maier, Benjamin Shepherd, Jordan Pober. YaleUniversity School of Medicine, New Haven, CT
Microvascular pericytes are contractile stromal cells thatstabilize blood capillaries and have great potential for use intissue engineering. Other stromal cell types, like mesench-ymal stem cells (MSC) and smooth muscle cells (SMC),reportedly inhibit T lymphocyte responses. Here we inves-tigate the immunologic functions of microvascular pericytes(PC) isolated from human placenta, comparing these cells tohuman umbilical vein endothelial cells (EC), to human aorticSMC and to human bone marrow-derived MSC. PC wereisolated and cultured by explant outgrowth from collage-nase-digested placental microvessel fragments in M199medium containing 20% fetal calf serum on tissue cultureplastic. Cultured PC are spindle-like with prominent actinfilaments and retract to form postconfluent multicellular
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