Bone marrow-derived mesenchymal stem cells decrease acute graft-versus-host disease after allogeneic hematopoietic stem cells transplantation

Graft-versus-host disease is a major complication of allogeneic hematopoietic stem cells transplantation, leading to serious morbidity and mortality. Mesenchymal stem cells(MSC)from bone marrow cause immunoregulation in vitro and in vivo. They also have the potential to protect from lethal GVHD after both autologous and allogeneic Hematopoietic Stem Cells Transplantation (HSCT). In this study, we investigated the mechanisms responsible for GVHD in the allo-HSCT co-transplantation with MSC condition. The model of acute GVHD in Rats was established using allogeneic HSC with donor-derived T cells transplantation, with or without additional donor-derived MSC co-transplantation. The degrees of GVHD were compared, the differentiation of CD4⁺, CD8⁺, Th1/Th2 and CD4⁺CD25⁺ T cells in vivo were assessed by flow cytometry and RT-PCR analyses. We found that MSC inhibited lethal GVHD after allo-HSCT. The value of CD8⁺ and CD4⁺ T cells and the ratio of Th1/Th2 T cell subsets decreased, at the same time the proportion of CD4⁺CD25⁺ T cells increased both in spleen lymphocytes and thymocytes in vivo after allo-HSCT with MSC co-transplantation compared with conventional allo-HSCT. Our results strongly suggested that BM-derived MSC has the function of preventing lethal GVHD after allo-HSCT by means of homeostasis of T subsets in vivo.     

Elimination of activated but not resting primary human CD4+ and CD8+ T cells by Fas ligand (FasL/CD95L)-expressing Killer-dendritic cells

Dendritic cells (DC) genetically engineered to express high levels of Fas ligand (FasL/CD95L) have been demonstrated to delete T cells in an antigen specific manner in several different animal models in vivo. However, the immunomodulatory capacity of primary human FasL-expressing Killer-DC has not been determined. Therefore, human Killer-DC were generated from mature monocyte-derived DC using the inducible CRE/LoxP adenoviral vector system, and the immunoregulatory capacity of these cells was analyzed in cocultures with primary human T cells in vitro. Combined transductions of DC by AdloxPFasL and AxCANCre resulted in FasL expression in >70% of DC without affecting the mature phenotype. Proliferation of activated primary human T cells was inhibited up to 80% in cocultures with FasL-expressing DC but not EGFP-transduced DC, which was due to induction of apoptosis in activated but not resting CD4⁺ and CD8⁺ T cells. Apoptosis induced by Killer-DC could be blocked by an anti-FasL-antibody in a dose dependent fashion. The present results demonstrate that FasL-expressing Killer-DC eliminate activated but not resting primary human CD4⁺ and CD8⁺ T cells by induction of Fas-mediated apoptosis supporting the concept to apply Killer-DC as a novel strategy for the treatment of T cell-dependent autoimmune disease and allograft rejection in humans.     

Human purified CD8+ T cells: Ex vivo expansion model to generate a maximum yield of functional cytotoxic cells

CD8⁺ T cells are a critical component of the cellular immune response. They play an important role in the control of viral infection and eliminating cells with malignant potential. However, attempts to generate and expand human CD8⁺ T cells in vitro for an adoptive immunotherapy have been conducted with limitation of the very low frequency of CD8⁺ T cells in blood. Therefore, several expansion protocols have been developed to obtain large and efficient numbers of human CD8⁺ T cells for use in adoptive immunotherapies. In this study various common culture conditions using different cytokines IL-2, IL-4, IL-7, IL-10, IL-12 and IL-15 and autologous feeders and sera were investigated to expand human purified CD8⁺ T cells. The importance and the influence of these factors on the growth and phenotype of CD8⁺ T cell were assessed by serially sampling cultures using flow cytometry. We demonstrated that combination of IL-2 (50U/ml) and autologous feeders induced maximal CD8⁺ T cell proliferation (40-50 folds) compared to other cytokines. Immunophenotypic analysis of cultured cells showed that expanded CD8⁺ T cells were activated and differentiated. Furthermore our expansion model also demonstrated that expanded CD8⁺ T cells are functionally cytotoxic active by killing Allogeneic LCLs cells. In conclusion, we have developed a reliable, simple method that uses minimal cell numbers to generate a high yield of functional cytotoxic CD8⁺ T cells, which can be used for the development of cellular immunotherapies.     

碳纳米管对树突状细胞成熟和T细胞分化作用研究

Th分化在免疫应答过程中起着关键性的作用,主要由树突状细胞来调控。碳纳米管是由碳元素组成的空心管状纳米材料,可作为抗原载体。碳纳米管对树突状细胞和Th分化的影响是决定其免疫响应的关键因素。分析氧化多壁碳纳米管(CNT)对小鼠骨髓来源的树突状细胞(BMDCs)功能的影响,以及对过敏抗原多肽OVA_323-339的 Th1和Th2免疫反应的影响。实验结果显示,BMDCs大量吞噬CNT,但对其细胞表面活化标志分子CD86、MHCII以及细胞因子TNF-α表达没有明显变化。CNT/抗原复合物可促进BMDCs表面MHCII的表达和CD8⁺T细胞增殖,增殖细胞的比例由28.7%分别增加到40.6%、41.3%和29.6%。Th2型细胞因子IL-4、IL-13和IL-10的表达和CD4⁺T的增殖受到抑制,增殖细胞的比例由54.4%减少到38.9%、46.6%和39.8%。研究结果提示,CNT不影响DCs的成熟和活化,但CNT可以影响过敏抗原的Th分化平衡,可抑制Th2型细胞因子的表达,促进Th1型免疫响应。     

Simultaneous Analysis of In Vivo CD8+ T Cell Cytotoxicity Against Multiple Epitopes using Multicolor Flow Cytometry

CD8+ T cells play a critical role in host defense against infections and tumors. Analysis of cytotoxic function of antigen-specific CD8+ T cells in animal models would be important in optimizing vaccine design against infections and tumors. In vivo cytotoxicity assays using fluorescent cellular dyes have been used as a popular alternative to traditionally used in vitro ⁵¹Cr-release assays. With the identification of multiple epitopes in various pathogen models, methods to simultaneously analyze cytotoxicity of CD8+ T cells to multiple epitopes in vivo would assist studies which aim to generate protective CD8+ T cell immunity to multiple epitopes. In this study, we evaluate the use of multiple fluorescent cellular dyes for the in vivo cytotoxicity assay. The use of 3 dyes allowed us to analyze the cytotoxicity of antigen-specific CD8+ T cell populations to multiple epitopes generated by virus infections, as well as their functional avidity, in vivo. Our studies extend the use of in vivo cytotoxicity assays to allow direct comparisons of cytotoxicity to various epitopes in the same animal and may also be applicable to assessment of in vitro cytotoxicity of human CD8+ T cells specific for multiple viral or tumor antigens in clinical settings.     

Role of CD4+ regulatory T cells in hyperbaric oxygen-mediated immune nonresponsiveness

We have previously shown that hyperbaric oxygen culture (HOC [95% O₂, 5% CO₂, 25 psi]) is an effective pretransplant tissue-modification technique that results in long-term allograft survival and the induction of systemic immune tolerance in a murine model. Here we address the immune modulatory effects of HOC-treatment of human immune responses using the in vitro mixed lymphocyte reaction (MLR). Pretreatment of allogeneic stimulator cells with HOC results in abrogation of cytotoxic T lymphocyte (CTL) activity, proliferative responses, and IFNγ production in a 7-day MLR. These responses can be restored either by the addition of IFNγ or IL-2 on day 0, or by blocking the activity of IL-4 and IL-10. The addition of IL-2 on day 4 does not restore allospecific CTL activity. The failure of HOC-treated cells to induce allospecific CTL is not due to the induction of anergy, demonstrated by the failure to restore responses after restimulation with allogeneic cells in the presence of IL-2. Removal of CD4⁺ cells prior to restimulation, results in restoration of CTL activity in MLR cultures restimulated with HOC-treated allogeneic cells. These results suggest that HOC-induced immune nonresponsiveness is mediated by the development of CD4⁺ regulatory cells in a Th2-type environment.     

Toll样受体1对间充质干细胞免疫调节Th17细胞的作用

背景：课题组前期研究表明间充质干细胞具有免疫调节Th17细胞的作用,但内在的调节机制尚待阐明,为此,针对Toll样受体1在其中的作用进行探讨,为今后潜在的细胞治疗策略提供可能的实验依据。目的：探讨Toll样受体1对间充质干细胞免疫调节Th17细胞的作用。方法：贴壁法分离人胚胎骨髓来源间充质干细胞,免疫磁珠法分离正常人CD4⁺ T细胞。CD4⁺ T细胞单独培养或与间充质干细胞共培养4 d。实时定量聚合酶链反应测定白细胞介素17、Toll样受体1相关基因的表达水平;流式细胞仪检测Th17细胞的数量。结果与结论：CD4⁺ T细胞及间充质干细胞均表达Toll样受体1。相对于CD4⁺单独培养组,间充质干细胞共培养组(间充质干细胞+CD4)白细胞介素17明显升高(3.59±0.11,1.14±0.08,P < 0.01);进一步发现Toll样受体1 mRNA表达水平亦相应升高(6.07±1.79,1.53±0.63,P < 0.01)。流式细胞仪检测发现,共培养组(间充质干细胞+CD4)Th17细胞数量明显高于CD4⁺ T细胞组[(4.53±1.27)%,(2.39±0.80)%,P < 0.01)。研究结果表明Toll样受体1可能参与间充质干细胞免疫调节人Th17细胞的作用。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

“Nk-Like” T Cytotoxicity Against B Lymphocytes in a Hypogammaglobulinemic Patient

Physiologically, cells with NK activity appear to exert a negative control on immunoglobulin production. The clinical association of large granular lymphocyte (LGL) proliferation with hypogammaglobulinemia suggests that these functional NK cells could also be involved in pathological situations.

We studied in vitro lymphocyte functions in a patient presenting LGL proliferation associated with hypogammaglobulinemia. The CD3⁺ CD8⁺ CD57⁺ CD16^- phenotype lymphocytes expressed a high NK type cytotoxicity towards K562 targets, suggesting that they may be considered as “NK-like” T cells. We cultured the patient peripheral blood mononuclear cells (PBMC) with control subject PBMC and with PBMC from two other subjects with B chronic lymphocytic leukemia (B- CLL) of the CD20⁺ CD21^- CD10^- phenotype. Patient PBMC exhibited a lytic activity on control PBMC and on the B lymphocytes of one of the two B- CLL but only in the presence of PWM. This activity was not exerted by the culture supernatant and required a cell - to - cell contact. We suggest that the hypogammaglobulinemia observed in this patient may be related to a cytotoxic effect exerted on B lymphocytes by a CD3⁺ CD8⁺ CD57⁺ CD16^- LGL proliferation.     

不同致敏模式支气管哮喘患儿外周血T淋巴细胞亚群比较及临床意义

目的：分析比较不同过敏原致敏模式下支气管哮喘患儿外周血T淋巴细胞亚群,为进一步明确不同变应原致敏哮喘患儿机体的免疫功能状态差异提供更多依据。方法：入组374例在北京儿童医院过敏反应科确诊的哮喘患儿,行过敏原皮肤点刺试验确定患儿致敏模式,流式细胞术测定外周血T细胞（CD3⁺CD19⁺）、CD4⁺T细胞（CD3⁺CD4⁺）、CD8⁺T细胞（CD3⁺CD8⁺）、Tregs（CD4⁺CD25⁺FOXP3⁺）、Th1（CD4⁺IFN-γ⁺T）、Th2（CD4⁺IL-4⁺T）以及Th17细胞亚群（CD4⁺IL-17A⁺T）,横断面比较上述免疫学指标在不同致敏模式哮喘患儿组间是否存在差异。结果：根据SPT检出阳性过敏原数量,将哮喘患儿分为未致敏哮喘组、单一致敏哮喘组及多重致敏哮喘三组。与健康对照组儿童相比,未致敏哮喘组、单一致敏哮喘组以及多重致敏哮喘三组哮喘患儿的外周血T细胞、CD4⁺T细胞、CD8⁺T细胞、CD4/CD8比值、Th1细胞、Th2细胞、Th1/Th2比值、Tregs、Th17细胞、Tregs/Th17比值等指标的组间差异均具有统计学意义。进一步对三组患儿进行两两比较发现,Tregs、Th17细胞以及Tregs/Th17比值在三组间差异具有统计学意义（均P<0.05）。根据SPT阳性检出过敏原种类,将入组哮喘患儿致敏谱主要分为尘螨组、霉菌组、动物皮屑组、花粉组及其他组。与健康对照组儿童相比,尘螨组、霉菌组、动物皮屑组、花粉组以及其他组过敏原致敏患儿的外周血T细胞、CD4⁺T细胞、CD8⁺T细胞、CD4/CD8比值、Th1细胞、Th2细胞、Th1/Th2比值、Tregs、Th17细胞、Tregs/Th17比值等指标的组间差异均具有统计学意义（均P<0.05）。同样地,行两两比较发现,五组患儿的外周血Th1细胞、Th2细胞、Th1/Th2比值、Tregs、Th17细胞以及Tregs/Th17比值在三组间差异具有统计学意义（均P<0.05）。结论：不同致敏模式的哮喘患儿外周血T淋巴细胞亚群分布状态存在差异,因此应注意不同致敏模式的哮喘患儿免疫应答状态差异。     

IL-1β促进nave T细胞向Th22细胞分化及在非小细胞肺癌中表达的相关性研究

目的:研究白细胞介素1β(IL-1β)促进nave T细胞向Th22细胞转化的机制及其在非小细胞肺癌患者外周血中表达的相关性和临床意义。方法:采用CD4~+nave T细胞磁珠分选试剂盒分离健康人外周血单个核细胞中的CD4~+nave T细胞,加入转化生长因子β和IL-2促进其分化增殖,分化过程中加入IL-1β诱导其向Th22细胞的分化,流式细胞术检测CD4~+IL-22~+T细胞的比例,ELISA检测IL-22的表达。选择我院确诊为非小细胞肺癌的患者60人,其中Ⅰ期18人,Ⅱ期20人,Ⅲ期13人,IV期9人,同时选择健康人25例,用流式细胞术检测外周血中Th22(CD4~+IL-22~+)细胞的比例,ELISA检测血清中IL-1β和IL-22的水平。结果:IL-1β可以诱导na6ve T细胞向Th22细胞转化并促进IL-22的分泌(P0.05)。非小细胞肺癌患者外周血中Th22细胞比例及IL-22和IL-1β的水平均高于健康人且与临床分期相关(P0.05)。结论:IL-1β可以诱导Th22细胞的分化和IL-22的表达,三者的水平和非小细胞肺癌的进展相关,可能参与免疫抑制并促进非小细胞肺癌的发生。     

Intracellular Th1/Th2 balance of pulmonary CD4(+) T cells in patients with active interstitial pneumonia evaluated by serum KL-6

The balance between CD4⁺ T helper (Th1) lymphocytes producing interferon-γ or Interleukin-4 (Th2) in the lungs may vary among diseases and during the progression of interstitial pneumonia (IP). Both idiopathic pulmonary fibrosis (IPF) and collagen vascular diseases (CVD) are associated with IP, but the clinical course and the response to treatment are different. Since Th1 or Th2 modulating drugs have been proven to alter the lymphocyte balance in vitro, it is important to elucidate the Th1/Th2 profile in patients with active IP. Bronchoalveolar lavage (BAL) was performed in patients who had IPF (n = 12) or CVD (n = 12) with IP, as well as in patients who had bronchoectasis and bronchopneumonia (n = 12). The CVD patients had rheumatoid arthritis (n = 6), Sjogren's syndrome (n = 2), dermatomyositis (n = 1), progressive systemic sclerosis (n = 2), and CREST syndrome (n = 1) as the underlying diseases. IP activity was evaluated by measuring serum KL-6, which is a clinically useful indicator for IP. The Th1/ Th2 balance and the CD4⁺/CD8⁺ ratio were determined for lymphocytes obtained from BAL by flow cytometric analysis. In IPF patients, the CD4⁺/CD8⁺ ratio was lower than in CVD patients. IPF patients showed Th2 dominance and CVD patients showed Th1 dominance when IP was active as evaluated by the serum KL-6 level. These data indicated that the Th1/Th2 balance of CD4⁺ T cells in the BAL differs between active IPF and CVD, even though KL-6 is elevated in both diseases. Therefore, the Th1/Th2 profile should be investigated to determine the use of Th1/Th2 modulator therapy for active IP with elevation of KL-6.     

Use of CFSE to Monitor Ex Vivo Regulatory T-cell Suppression of CD4+ and CD8+ T-cell Proliferation within Unseparated Mononuclear Cells from Malignant and Non-Malignant Human Lymph Node Biopsies

Regulatory T-cells (Tregs) play a critical role in the inhibition of self-reactive immune responses and as such have been implicated in the suppression of anti-tumor immunity. A clearer understanding of the mechanisms by which Tregs suppress effector T-cell responses within the context of anti-tumor immunity may lead to more effective treatments. The study of Tregs, particularly in the context of ongoing active immune responses, has been challenging due to the lack of surface molecules truly unique to these cells. Several surface markers have been shown to be constitutively expressed by Tregs, such as high levels of CD25, GITR and CTLA-4, and thus have been useful for their study. However, the heterogeneity of surface marker expression still makes identifying Tregs ex vivo challenging. As such, the only means available, currently, to accurately identify Tregs ex vivo is through functional suppression assays. Tregs have been shown to inhibit a variety of cellular functions including T-cell proliferation and as such, in vitro inhibition of proliferation is routinely used as a measure of Treg-mediated suppression. Several assays currently exist to assay cellular proliferation, including [³H]thymidine incorporation and CFSE dilution. However, a limitation of using [³H]thymidine is the difficulty differentiating between proliferation of the target cells and that of the Tregs themselves. Due to the ability to differentiate by flow cytometric analysis between labeled and unlabelled cells using CFSE, in contrast to [³H]thymidine, it is possible to analyze the proliferation of labeled target cells separate from unlabeled Tregs in co-culture experiments. In addition, the use of multi-color flow cytometry allows for the analysis of different T-cell subsets simultaneously without the necessity to separate these cells. Thus, CFSE has several advantages to [³H]thymidine for analysis of cellular proliferation. Herein we describe our work utilizing CFSE labeling to assess, (1) proliferative responses of CD4⁺ and CD8⁺ T-cells in unseparated single cell suspensions from human lymph nodes and, (2) the ability of tumor infiltrating suppressive populations, including Tregs, isolated from neoplastic lymph nodes to suppress in vitro proliferation of allogeneic CD4⁺ and CD8⁺ T-cells isolated from peripheral blood of healthy donors.     

脂肪源性干细胞对多发性硬化患者Th17的免疫调控作用

 目的: 探讨人脂肪源性干细胞(hASCs)对多发性硬化(MS)患者外周血辅助性T细胞17(Th17)的免疫调控作用机制。方法: 分离、纯化脂肪组织中的hASCs。采用密度梯度离心法分离MS患者外周血单个核细胞(PBMCs),磁珠分选CD4⁺T细胞,体外刺激细胞向Th17极化,并加入不同比例的hASCs(hASCs:CD4⁺T为1:4和1:10)共培养4 d,设立添加anti-LIF抗体组;流式细胞术检测共培养后Th17细胞占CD4⁺T细胞的比例,real-time PCR检测白细胞介素6受体(IL-6R)、白细胞介素23受体(IL-23R)、白血病抑制因子受体(LIFR)、维甲酸相关孤儿受体γt(RORγt)及白血病抑制因子(LIF)的mRNA水平变化;ELISA法检测共培养体系上清液中LIF的水平。结果: 分离的hASCs经流式细胞术鉴定可基本判定为hASCs;PBMCs经磁珠法分选后获得90%以上纯度的CD4⁺T细胞。共培养后,1:4组和1:10组中Th17细胞所占比例下降,且存在高浓度抑制效应;共培养后RORγt、IL-6R和IL-23R的mRNA表达水平下降,LIFR和LIF的mRNA表达水平均升高;加入anti-LIF抗体后,Th17细胞比例回升至对照组水平;RORγt和IL-6R的mRNA表达水平回升;ELISA检测各组LIF的水平,共培养组LIF分泌均较对照组明显增多,加入anti-LIF抗体后明显减少。结论: hASCs可抑制MS患者Th17细胞的分化,其作用可能与其分泌LIF、通过IL-6/LIF轴竞争性抑制有关。     

Triggering of T cell-mediated immune responses by allogenic tumor cell vaccine in patients with oral cancer

We investigated the immunomodulatory activity of allogenic whole tumor cell vaccine in oral cancer patients in vitro by two-color flow cytometry. Vaccine treatment significantly increased the expression of CD69 and HLA-DR in CD3⁺ T-cell subsets. The frequency of Interferon-gamma and Interleukin (IL)-2 expressing CD4⁺/CD8⁺ T-cell subsets was significantly higher with a concomitant reduction in IL-4 and IL-10 expressing T-cells in the vaccine treated group as compared with the untreated controls. Vaccine treatment significantly increased T-cell receptor (TCR), Vβ3, Vβ5 and Vβ8 usage. The results indicate that the allogenic whole tumor cell vaccine is able to trigger T-cell mediated immunity in patients with intraoral squamous cell carcinoma.     

Tumor transfected with CCL21 enhanced reactivity and apoptosis resistance of human monocyte-derived dendritic cells

Chemokine CCL21 can effectively attract CCR7⁺ dendritic cells (DCs), however its role in this event is poorly understood. In this report, we investigated the effect of exogenous CCL21 expressed in breast cancer MCF-7 on human monocyte-derived DCs. CCL21-transfected MCF-7 stimulation prompted DC functions: migration, antigen-uptake and presentation. The stimulated DCs facilitated Th1 type cytokines production, perforin-forming CD8⁺ T cell transformation and final T cell-associated clearance of MCF-7. Moreover, the MCF-7-resourced CCL21 protected DCs from apoptosis significantly, involving up-regulations of Bcl-2 expression and NF-κB activity, and reduction of caspase-3. This study provides evidence that tumor-derived CCL21 increases the presentation and apoptosis resistance of DCs, suggesting such a mechanism may be useful for the improvement of tumor cell immunogenicity and anti-tumor response.     

A study of CD45RO, CD45RA and CD29 antigen expression on human decidual T cells in an early stage of pregnancy

The decidua is the place where the fertilized egg is implanted and where the immunocompetent cells of the mother come into direct contact with genetically disparate cells of the conceptus. Although the T cells in the decidua are exposed to fetal antigens, the fetus is not rejected by maternal immunocompetent cells. In the present study, we examined surface markers to determine whether the T cells in the human decidua are naive T cells without or memory T cells with a history of antigen stimulation. Although few T cells were present in the decidua, as compared to the peripheral blood, CD45RO⁺, CD29⁺ and CD45RA⁻ CD4⁺ T cells as well as CD45RO⁻, CD29⁺ and CD45RA⁻ CD8⁺ T cells, which are considered to be memory T cells, were in the majority, with only small numbers of CD45RO⁻, CD29⁻ and CD45RA⁺ CD4⁺ and CD8⁺ cells, which are naive T cells, present. Also, the decidual mononuclear cells secreted IL-2 and IL-4. Since IL-4 is secreted only by memory T cells, it is suggested that in the decidua memory T cells increase in number and secrete cytokines, thereby in some way influencing the phenomenon of fertility.     

No in vitro evidence for a decreased alloreactivity toward noninherited maternal HLA antigens in healthy individuals

Pre- and/or perinatal exposure to noninherited maternal HLA antigens (NIMA) is associated with a decreased HLA antibody formation against the NIMA and a significantly better graft survival of kidney grafts from siblings or those from unrelated donors who were mismatched for the NIMA haplotype compared with the NIPA (noninherited paternal HLA antigens) haplotype later in life. These observations suggest that some form of immunological tolerance against NIMA is induced. We analyzed the in vitro T cell reactivity of healthy individuals toward their parents and/or siblings expressing the NIMA or NIPA haplotype to explore whether the alloimmune response to NIMA has distinct characteristics compared with NIPA. No differences were detected by mixed lymphocyte reactions (MLR) and supernatants taken from the MLR showed no differences in IFN-γ and IL-10 production. Additionally, no differences were found with IFN-γ and IL-10 Elispot analyses. Phenotypic analysis revealed no selective increase in the number of CD3⁻CD8^dim cells (thought to be a NK-like regulator cell) and the number of CD4⁺CD25⁺CD152⁺ cells (naturally occurring regulatory T cells) after stimulation with NIMA-expressing cells when compared with NIPA-expressing cells. In conclusion, no evidence of an influence of a NIMA effect on the cellular level was found in healthy individuals with “standard” immunological techniques.     

Induction of anergic and regulatory T cells by plasmacytoid dendritic cells and other dendritic cell subsets

The induction of antigen-specific tolerance is critical for maintaining immune homeostasis and preventing autoimmunity. Because the central tolerance that eliminates potentially harmful autoreactive T cells is incomplete, peripheral mechanisms for suppressing self-reactive T cells play an important role. Dendritic cells (DCs) are professional antigen-presenting cells, which have an extraordinary capacity to stimulate naïve T cells and initiate primary immune responses. Recent accumulating evidence indicates that several subsets of human DCs also play a critical role in the induction of peripheral tolerance by anergizing effector CD4⁺ and CD8⁺ T cells or by inducing the differentiation of naïve T cells into T-regulatory cells, which produce interleukin (IL)-10. Human DC subsets with the property of suppressing an antigen-specific T-cell response include plasmacytoid DCs, which are either in an immature state or in a mature state induced by CD40 ligand stimulation, and monocyte-derived DCs, which are either in an immature state or have had their state modulated by treatment with IL-10 or CD8⁺CD28⁻ T cells. These “tolerogenic” DCs may be relevant to therapeutic applications for autoimmune and allergic diseases as well as organ transplant rejection.     

Regulation of Th1/Th2 development by antigen-presenting cells in vivo

The aim of this work was to test whether the nature of the antigen-presenting cell influences the Th1/Th2 balance in vivo. Adoptive transfer of dendritic cells or macrophages, pulsed extracorporeally with antigen, results in antigen-specific T cell priming. Of note, macrophages and dendritic cells appear to differentially regulate the development of T lymphocytes. In addition, the population of splenic dendritic cells appears heterogeneous and includes the CD8a⁺ and CD8a⁻ subclasses which direct the differentiation of Th1 and Th2 cells, respectively. Using neutralizing antibodies and mice genetically deficient for various cytokines, we evaluated the role of several molecules in the development of Tcells in vivo. Our observations emphasize the role of CD86 and IL-6 for Th2 priming by macrophages, CD86 for Th1 priming by dendritic cells and IL-12 for Th1 priming by dendritic cells.