scholarly journals Immunomodulatory Role and Therapeutic Potential of Non-Coding RNAs Mediated by Dendritic Cells in Autoimmune and Immune Tolerance-Related Diseases

2021 ◽  
Vol 12 ◽  
Author(s):  
Yifeng Liu ◽  
Xiaoze Wang ◽  
Fan Yang ◽  
Yanyi Zheng ◽  
Tinghong Ye ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Autoimmune Diseases ◽  
Immune Tolerance ◽  
Therapeutic Potential ◽  
The Body ◽  
Cytokines And Chemokines ◽  
Non Coding Rnas ◽  
And Function ◽  
Antigen Presenting

Dendritic cells (DCs) are professional antigen-presenting cells that act as a bridge between innate immunity and adaptive immunity. After activation, DCs differentiate into subtypes with different functions, at which point they upregulate co-stimulatory molecules and produce various cytokines and chemokines. Activated DCs also process antigens for presentation to T cells and regulate the differentiation and function of T cells to modulate the immune state of the body. Non-coding RNAs, RNA transcripts that are unable to encode proteins, not only participate in the pathological mechanisms of autoimmune-related diseases but also regulate the function of immune cells in these diseases. Accumulating evidence suggests that dysregulation of non-coding RNAs contributes to DC differentiation, functions, and so on, consequently producing effects in various autoimmune diseases. In this review, we summarize the main non-coding RNAs (miRNAs, lncRNAs, circRNAs) that regulate DCs in pathological mechanisms and have tremendous potential to give rise to novel therapeutic targets and strategies for multiple autoimmune diseases and immune tolerance-related diseases.

scholarly journals TIGIT-Fc as a Potential Therapeutic Agent for Fetomaternal Tolerance

2021 ◽  
Vol 12 ◽  
Author(s):  
Wenyan Fu ◽  
Renfei Cai ◽  
Zetong Ma ◽  
Tian Li ◽  
Changhai Lei ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Cell ◽  
Therapeutic Potential ◽  
Interleukin 10 ◽  
Immunological Tolerance ◽  
Tolerogenic Dendritic Cells ◽  
Immune Cell Subsets ◽  
Pregnant Mice ◽  
Antigen Presenting

The perfect synchronization of maternal immune-endocrine mechanisms and those of the fetus is necessary for a successful pregnancy. In this report, decidual immune cells at the maternal-fetal interface were detected that expressed TIGIT (T cell immunoreceptor with Ig and ITIM domains), which is a co-inhibitory receptor that triggers immunological tolerance. We generated recombinant TIGIT-Fc fusion proteins by linking the extracellular domain of TIGIT and silent Fc fragments. The treatment with TIGIT-Fc of human decidual antigen presenting cells (APCs), the decidual dendritic cells (dDCs), and decidual macrophages (dMϕs) increased the production of interleukin 10 and induced the decidua APCs to powerfully polarize the decidual CD4+ T cells toward a classic TH2 phenotype. We further proposed that Notch signaling shows a pivotal effect on the transcriptional regulation in decidual immune cell subsets. Moreover, the administration of TIGIT-Fc to CBA/J pregnant mice at preimplantation induced CD4+ forkhead box P3+ (Foxp3+) regulatory T cells and tolerogenic dendritic cells and increased pregnancy rates in an abortion-prone animal model stress. The results suggested the therapeutic potential of the TIGIT-Fc fusion protein in reinstating immune tolerance in failing pregnancies.

scholarly journals Extracorporeal photopheresis as a non-specific immune therapy of autoimmune diseases and skin T-cell lymphoma (a review of the literature and own studies)

2019 ◽  
Vol 47 (5) ◽  
pp. 419-434
Author(s):  
A. V. Kil'dyushevskiy ◽  
V. A. Molochkov ◽  
T. A. Mitina ◽  
Ya. G. Moysyuk ◽  
A. V. Molochkov
Keyword(s):  
T Cells ◽  
T Cell ◽  
Autoimmune Diseases ◽  
Immune Tolerance ◽  
Immune Therapy ◽  
Effector Memory ◽  
Target Cells ◽  
Cytotoxic Lymphocytes ◽  
Extracorporeal Photopheresis ◽  
Antigen Presenting

Aim: To present well-known and disputable mechanisms of the effects of extracorporeal photopheresis (ECP) in heterogeneous clinical conditions, as well as to demonstrate its advantages over conventional hormonal, immunosuppressive and cytostatic treatments, with a recommendation to widely implement it into practical management of autoimmune disease and cutaneous T-cell lymphomas (CTCLs).Key points: Despite convincing evidence of the ECP efficacy in the treatment of T-cell mediated disorders, a unifying concept of its mechanism has not been established so far. In this review, we attempted to determine the value of multiple, sometimes contradictory and equivocal points of view to immunobiochemical processes underlying the restoration of mechanism of immune tolerance in some autoimmune diseases and CTCLs. We focused our attention on our own clinical and immunological data obtained during a 20-years' experience with the use of ECP in clinical departments of MONIKI (Russia). Based on this, we have shown that ECP is more effective in autoimmune diseases than conventional treatment approaches with hormones, immunosuppressants and cytostatics. Unlike them, ECP is selectively targeted to auto-aggressive T-cells without induction of systemic immunosuppression. The leading role is played by the transformation of activated (immunogenic) myeloid dendrite cells (DC) into tolerogenic cell associated with their synthesis of inhibitor cytokines. The interplay of the cytokines with an antigen results in polarization of CD4+ Т lymphocytes via the Th2 pathway with restoration of the Th1/Th2 balance and their cytokine production. ECP triggers regulatory anti-clonotypic effector memory cells at the end stage of CD3+/CD8+/CD27-/CD28-/CD62L+ differentiation, that provide and maintain the peripheral immune tolerance, by deletion of the clone of auto-reactive cytotoxic lymphocytes and inducing their apoptosis. In autoimmune disorders, ECP results in reduction of the expression of integrin adhesion molecules on auto-reactive cell membranes with subsequent loss of their ability to migrate through the endothelium to their target cells. In its turn, it leads to decreasing immunoinflammatory response in the lesion. Both clinical and experimental data indicate that the mechanism of ECP action against CTCLs is characterized by activation of tumor cell apoptosis, unblocking of co-activation receptors on the antigen-presenting DC providing the functioning of the second signaling pathway for T lymphocyte activation. This results in proliferation of anti-tumor effector cells pool, production of DC activating cytokines that participate in the CD4+ polarization via Th1 pathway. In addition, this review considers the mechanism of the immunomodulating effect of ECP in the context of its influence at the levels of transcription and translation of proteins contributing to the pathophysiology of the disorders, based on molecular immunogenetic studies. Thus, ECP is able to induce antigen-specific immunological tolerance through the transformation of antigen-presenting cells, modulation of cytokine profile, adhesion and activation molecules, as well as through formatting of the regulatory T cells (Tregs).Conclusion: Undoubtedly, the immunobiological ECP technique has significant advantages over well-known conventional hormonal, immunosuppressive, and cytostatic therapies of autoimmune diseases and CTCLs.

scholarly journals Regulatory T Cells Accumulate and Proliferate in the Ischemic Hemisphere for up to 30 Days after MCAO

2012 ◽  
Vol 33 (1) ◽  
pp. 37-47 ◽  
Author(s):  
Tobias Stubbe ◽  
Friederike Ebner ◽  
Daniel Richter ◽  
Odilo Randolf Engel ◽  
Juliane Klehmet ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Regulatory T Cells ◽  
De Novo ◽  
Temporal Distribution ◽  
Artery Occlusion ◽  
Ki 67 ◽  
And Function ◽  
Antigen Presenting ◽  
Cerebral Artery Occlusion

Local and peripheral immune responses are activated after ischemic stroke. In our present study, we investigated the temporal distribution, location, induction, and function of regulatory T cells (Tregs) and the possible involvement of microglia, macrophages, and dendritic cells after middle cerebral artery occlusion (MCAO). C57BL/6J and Foxp3EGFP transgenic mice were subjected to 30 minutes MCAO. On days 7, 14, and 30 after MCAO, Tregs and antigen presenting cells were analyzed using fluorescence activated cell sorting multicolor staining and immunohistochemistry. A strong accumulation of Tregs was observed on days 14 and 30 in the ischemic hemisphere accompanied by the elevated presence and activation of microglia. Dendritic cells and macrophages were found on each analyzed day. About 60% of Foxp3+ Tregs in ischemic hemispheres were positive for the proliferation marker Ki-67 on days 7 and 14 after MCAO. The transfer of naive CD4+ cells depleted of Foxp3+ Tregs into RAG1−/– mice 1 day before MCAO did not lead to a de novo generation of Tregs 14 days after surgery. After depletion of CD25+ Tregs, no changes regarding neurologic outcome were detected. The sustained presence of Tregs in the brain after MCAO indicates a long-lasting immunological alteration and involvement of brain cells in immunoregulatory mechanisms.

scholarly journals TIGIT-Fc Promote Immune Tolerance at the Feto-maternal Interface

2019 ◽  
Author(s):  
Wenyan Fu ◽  
Zetong Ma ◽  
Changhai Lei ◽  
Min Ding ◽  
Shi Hu
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Immune Tolerance ◽  
Immune Cell ◽  
Therapeutic Potential ◽  
Interleukin 10 ◽  
Immunological Tolerance ◽  
Direct Role ◽  
Tolerogenic Dendritic Cells ◽  
Pregnant Mice

AbstractThe perfect synchronization of maternal immune-endocrine mechanisms and those of the foetus is necessary for a successful pregnancy. In this report, decidual immune cells at the maternal-foetal interface were detected that expressed TIGIT (T cell immunoreceptor with Ig and ITIM domains), which is a co-inhibitory receptor that triggers immunological tolerance. We generated recombinant TIGIT-Fc fusion proteins by linking the extracellular domain of TIGIT and silent Fc fragments. The treatment with TIGIT-Fc of human decidual dendritic cells (dDCs) increased the production of interleukin 10 and induced the dDCs to powerfully polarize the decidual CD4+ T cells towards a classic TH2 phenotype. The administration of TIGIT-Fc to CBA/J pregnant mice at preimplantation induced CD4+ forkhead box P3+ (Foxp3+) regulatory T cells and tolerogenic dendritic cells and increased pregnancy rates in a mouse model of abortive stress. Moreover, we proposed that progesterone play a direct role in the transcriptional regulation of the TIGIT gene in decidual immune cell subsets. The results suggested the therapeutic potential of the TIGIT-Fc fusion protein in reinstating immune tolerance in failing pregnancies.

Curcumin: a dietary phytochemical for targeting the phenotype and function of dendritic cells

2020 ◽  
Vol 27 ◽  
Author(s):  
Kaveh Rahimi ◽  
Kambiz Hassanzadeh ◽  
Hashem Khanbabaei ◽  
Saeed Mohammadian Haftcheshmeh ◽  
Abbas Ahmadi ◽  
...  
Keyword(s):  
Dendritic Cells ◽  
Immune Responses ◽  
Intracellular Signaling ◽  
T Helper 1 ◽  
Cytokines And Chemokines ◽  
Wide Range ◽  
Health And Disease ◽  
And Function ◽  
Antigen Presenting ◽  
Tolerogenic Dcs

: Dendritic cells (DCs) are the most powerful antigen-presenting cells which link the innate and adaptive immune responses. Depending on the context DCs initiate the immune responses or contribute to immune tolerance. Any disturbance in their phenotypes and functions may initiate inflammatory or autoimmune diseases. Hence, dysregulated DCs are the most attractive pharmacological target for the development of new therapies aiming at reducing their immunogenicity and at enhancing their tolerogenicity. Curcumin is the polyphenolic phytochemical component of the spice turmeric with a wide range of pharmacological activities. It acts in several ways as a modulator of DCs and converts them into tolerogenic DCs. Tolerogenic DCs possess anti-inflammatory and immunomodulatory activities that regulate the immune responses in health and disease. Curcumin by blocking maturation markers, cytokines and chemokines expression, and disrupting the antigen-presenting machinery of DCs render them non- or hypo-responsive to immunostimulants. It also reduces the expression of co-stimulatory and adhesion molecules on DCs and prevents them from both migration and antigen presentation but enhances their endocytosis capacity. Hence, curcumin causes DCs-inducing regulatory T cells and dampens CD4+ T helper 1 (Th1), Th2, and Th17 polarization. Inhibition of transcription factors such as NF-κB, AP-1, MAPKs (p38, JNK, ERK) and other intracellular signaling molecules such as JAK/STAT/SOCS provide a plausible explanation for most of these observations. In this review, we summarize the potential effects of curcumin on the phenotypes and functions of DCs as the key players in orchestration, stimulation, and modulation of the immune responses.

CD47 Engagement Impairs the Function and Maturation of Human Dendritic Cells Via the Inhibition of NF-κB Avtivity.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 3807-3807
Author(s):  
Jing Yu ◽  
Maofang Lin
Keyword(s):  
Flow Cytometry ◽  
Dendritic Cells ◽  
T Cell ◽  
Dna Binding ◽  
Immune Tolerance ◽  
Binding Activity ◽  
Mixed Leukocyte Reaction ◽  
Hla Dr ◽  
And Function ◽  
Antigen Presenting

Abstract OBJECTIVE Dendritic cells (DCs) are important functional antigen-presenting cells that play an essential role in initiating and modulating immune responses. Their mature states are crucial for the induction of T-cell-mediated immune reactions. Therefore, The mechanism of T cell anergy related with DCs and research in applying immature DCs to establish donor-specific immune tolerance have become one of the new frontiers in the field of transplantation immunity. The activation of nuclear factor kappa B(NF-κB) has been said to modulate the maturation of DCs, which controls the transcription of genes encoding major histocompatibility complex(MHC)antigens, and costimulator molecules for T cell activation. The CD47 Ag, a multispan transmembrane ptotein expressed on all hemopoietic cells, has an immunosuppressive function with its ligand, monoclonal antibody (mAb) or thrombospondin. In the current study, we investigate the influence of CD47 engagement by its soluble mAb B6H12 on the maturation and function of cultured DCs. Further to observe any results could be ascribed to the effect of B6H12 mAb on the nuclear translocation and DNA binding of NF-κB. METHODS Monocyte-derived DCs were propagated in granulocyte-macrophage colony stimulating factor (GM-CSF) combined with lipopolysaccharide (LPS) and interleukin(IL)-4, in the presence or absence of soluble anti-CD47 monoclonal antibodies (anti-CD47 mAbs, B6H12). The phenotype of DCs(CD80, CD86, CD83, CD1a, HLA-DR) were detected by the flow cytometry. Semi-quantitative RT-PCR and ELISA methods were used to analyse the mRNA and protein expression levels of interleukin-12(IL-12). The antigen-presenting functions of DCs were determined in one-way mixed leukocyte reaction by Brdu-ELISA. Electrophoretic mobility shift assay (EMSA) was applied to examine the activity of NF-κB. RESULTS Both the immature and the mature DCs express CD47, which has a ratio of 94-98%. The cell immune phenotype was lower in B6H12 mAb treated DC group than that in untreated groups. The data were as follow:CD80+(68.14±7.41)% vs (89.17±8.59)%; CD86+ (67.33±4.71)% vs (87.27±3.56)%;CD83(40.08±14.80)% vs (72.77±8.68)%;Cdla+(66.45±4.06)% vs (95.93±3.03)%; HLA-DR(40.67±13.48) vs (98.97±1.01)%, respectively. The mRNA levels of IL-12 P40 was decreased (P<0.01) with the treatment of B6H12 mAb. Pre-exposure of developing DCs to 10μg/ml B6H12 considerably reduced their subsequent ability to secret IL-12 P70 upon stimulation by LPS, comparing with the other two control groups [(36.6±3.83)pg/ml vs (80.43±8.24)pg/ml vs(83.7±9.58 )pg/ml] (P<0.05). It is also noted that the inhibition of IL-12 P70 release by B6H12 mAb was dependent on dose at the range of 2.5 - 10μg/ml, and the inhibition can be seen in DCs treated with B6H12 mAb at the dose of 2.5μg/ml. The data of the mixed leukocyte reaction were consistent with the flow cytometry results (P<0.01). Pre-exposure to B6H12 mAb during the development of DCs resulted in a dramatic decrease of the DNA binding activity toward protein in the nucleus. Moreover, this inhibition was also seemed to be dose dependent (2.5μg/ml, 5μg/ml, 10μg/ml) and the density scan values were:126.1±4.32, 103.46±10.96, 72.80±10.08. CONCLUSION This results indicate that the CD47 ligation by B6H12 mAb exerts a negative effect on the maturation and function of in vitro cultured DCs through the inhibition of NF-κB binding activity, which suggest its favorable role in the induction of modulation of immune tolerance.

scholarly journals THU0051 LOW-DOSE INTERLEUKIN-2 SELECTIVELY EXPAND AND ACTIVATE REGULATORY T CELLS ACROSS 13 AUTOIMMUNE DISEASES.

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 237.1-238
Author(s):  
M. Rosenzwajg ◽  
R. Lorenzon ◽  
P. Cacoub ◽  
F. Pitoiset ◽  
S. Aractingi ◽  
...  
Keyword(s):  
T Cells ◽  
Regulatory T Cells ◽  
Autoimmune Diseases ◽  
Inflammatory Disease ◽  
Low Dose ◽  
Therapeutic Potential ◽  
Interleukin 2 ◽  
Clinical Effects ◽  
Research Support ◽  
Open Label

Background:Regulatory T cells (Tregs) prevent autoimmunity and control inflammation. As low-dose interleukin-2 (ld-IL2) expands and activates Tregs, it has a broad therapeutic potential for any autoimmune or inflammatory disease (AIID). We performed a disease-finding “basket trial” (TRANSREGNCT01988506) in patients affected by one of 11 different AIID and reported the outcome of the first 46 patients (Rosenzwajg et al, ARD 2019).Objectives:Here we analyzed and discussed results from deep immunophenotyping, of 78 patients, to comprehensively study the effect of ld-IL2 on the immune system of patients affected by various AIIDMethods:We performed a prospective, open label, phase I-IIa study in 78 patients with a mild to moderate form of one of 13 selected AIID. All patients received ld-IL2 (1 million IU/day) for 5 days, followed by fortnightly injections for 6 months. Deep immunophenotyping was performed before and after 5 days of ld-IL2.Results:ld-IL2 significantly expands both memory Tregs as well as naïve Tregs, including recent thymic emigrant Tregs. It also activates Tregs as demonstrated by the significantly increased expression of HLA-DR, CD39, CD73, GITR, CTLA-4. Similar results were observed across the different AIID.Conclusion:ld-IL2 “universally” improves Treg fitness across 13 autoimmune and inflammatory disease.References:[1]Rosenzwajg M#, Lorenzon R#, Cacoub P, Pham HP, Pitoiset F, El Soufi K, RIbet C, Bernard C, Aractingi S, Banneville B, Beaugerie L, Berenbaum F, Champey J, Chazouilleres O, Corpechot C, Fautrel B, Mekinian A, Regnier E, Saadoun D, Salem JE, Sellam J, Seksik P, Daguenel-Nguyen A, Doppler V, Mariau J, Vicaut E, Klatzmann D. Immunological and clinical effects of low-dose interleukin-2 across 11 autoimmune diseases in a single, open clinical trial. Ann Rheum Dis. 2019 Feb;78(2):209-217. doi: 10.1136/annrheumdis-2018-214229. Epub 2018 Nov 24.Disclosure of Interests:Michelle Rosenzwajg: None declared, Roberta Lorenzon: None declared, Patrice cacoub: None declared, Fabien Pitoiset: None declared, Selim Aractingi: None declared, Beatrice Banneville Speakers bureau: Lilly, Novartis, Laurent Beaugerie: None declared, Francis Berenbaum Grant/research support from: TRB Chemedica (through institution), MSD (through institution), Pfizer (through institution), Consultant of: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Bone Therapeutics, Regulaxis, Peptinov, 4P Pharma, Paid instructor for: Sandoz, Speakers bureau: Novartis, MSD, Pfizer, Lilly, UCB, Abbvie, Roche, Servier, Sanofi-Aventis, Flexion Therapeutics, Expanscience, GSK, Biogen, Nordic, Sandoz, Regeneron, Gilead, Sandoz, Julien Champey: None declared, Olivier Chazouilleres: None declared, Christophe Corpechot: None declared, Bruno Fautrel Grant/research support from: AbbVie, Lilly, MSD, Pfizer, Consultant of: AbbVie, Biogen, BMS, Boehringer Ingelheim, Celgene, Lilly, Janssen, Medac MSD France, Nordic Pharma, Novartis, Pfizer, Roche, Sanofi Aventis, SOBI and UCB, Arsene Mekinian: None declared, Elodie Regnier: None declared, david Saadoun: None declared, Joe-Elie Salem: None declared, Jérémie SELLAM: None declared, Philippe Seksik: None declared, David Klatzmann Consultant of: ILTOO Pharma

Stimulation of autologous proliferative and cytotoxic T-cell responses by “leukemic dendritic cells” derived from blast cells in acute myeloid leukemia

Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2764-2771 ◽  
Author(s):  
Beth D. Harrison ◽  
Julie A. Adams ◽  
Mark Briggs ◽  
Michelle L. Brereton ◽  
John A. Liu Yin
Keyword(s):  
T Cells ◽  
Acute Myeloid Leukemia ◽  
Dendritic Cells ◽  
T Cell ◽  
Myeloid Leukemia ◽  
T Cell Responses ◽  
Cell Responses ◽  
Antigen Presenting ◽  
Acute Myeloid ◽  
Stimulation Of

Abstract Effective presentation of tumor antigens is fundamental to strategies aimed at enrolling the immune system in eradication of residual disease after conventional treatments. Myeloid malignancies provide a unique opportunity to derive dendritic cells (DCs), functioning antigen-presenting cells, from the malignant cells themselves. These may then co-express leukemic antigens together with appropriate secondary signals and be used to generate a specific, antileukemic immune response. In this study, blasts from 40 patients with acute myeloid leukemia (AML) were cultured with combinations of granulocyte-macrophage colony-stimulating factor, interleukin 4, and tumor necrosis factor α, and development to DCs was assessed. After culture, cells from 24 samples exhibited morphological and immunophenotypic features of DCs, including expression of major histocompatibility complex class II, CD1a, CD83, and CD86, and were potent stimulators in an allogeneic mixed lymphocyte reaction (MLR). Stimulation of autologous T-cell responses was assessed by the proliferative response of autologous T cells to the leukemic DCs and by demonstration of the induction of specific, autologous, antileukemic cytotoxicity. Of 17 samples, 11 were effective stimulators in the autologous MLR, and low, but consistent, autologous, antileukemic cytotoxicity was induced in 8 of 11 cases (mean, 27%; range, 17%-37%). This study indicates that cells with enhanced antigen-presenting ability can be generated from AML blasts, that these cells can effectively prime autologous cytotoxic T cells in vitro, and that they may be used as potential vaccines in the immunotherapy of AML.

Functional domains of HSP70 stimulate generation of cytokines and chemokines, maturation of dendritic cells and adjuvanticity

2004 ◽  
Vol 32 (4) ◽  
pp. 629-632 ◽  
Author(s):  
T. Lehner ◽  
Y. Wang ◽  
T. Whittall ◽  
E. McGowan ◽  
C.G. Kelly ◽  
...  
Keyword(s):  
Amino Acids ◽  
Dendritic Cells ◽  
Immune Responses ◽  
Cd40 Ligand ◽  
Interleukin 12 ◽  
Cytokines And Chemokines ◽  
Cc Chemokines ◽  
Factor Α ◽  
Antigen Presenting ◽  
Necrosis Factor

Microbial HSP70 (heat-shock protein 70) consists of three functionally distinct domains: an N-terminal 44 kDa ATPase portion (amino acids 1–358), followed by an 18 kDa peptide-binding domain (amino acids 359–494) and a C-terminal 10 kDa fragment (amino acids 495–609). Immunological functions of these three different domains in stimulating monocytes and dendritic cells have not been fully defined. However, the C-terminal portion (amino acids 359–610) stimulates the production of CC chemokines, IL-12 (interleukin-12), TNFα(tumour necrosis factor α), NO and maturation of dendritic cells and also functions as an adjuvant in the induction of immune responses. In contrast, the ATPase domain of microbial HSP70 mostly lacks these functions. Since the receptor for HSP70 is CD40, which with its CD40 ligand constitutes a major co-stimulatory pathway in the interaction between antigen-presenting cells and T-cells, HSP70 may function as an alternative ligand to CD40L. HSP70–CD40 interaction has been demonstrated in non-human primates to play a role in HIV infection, in protection against Mycobacterium tuberculosis and in conversion of tolerance to immunity.

scholarly journals Response of naive antigen-specific CD4+ T cells in vitro: characteristics and antigen-presenting cell requirements.

1992 ◽  
Vol 176 (5) ◽  
pp. 1431-1437 ◽  
Author(s):  
M Croft ◽  
D D Duncan ◽  
S L Swain
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
T Cell ◽  
Cd4 T Cells ◽  
Cd4 Cells ◽  
Peptide Antigen ◽  
Naive T Cells ◽  
Naïve T Cells ◽  
Antigen Presenting

Because of the low frequency of T cells for any particular soluble protein antigen in unprimed animals, the requirements for naive T cell responses in specific antigens have not been clearly delineated and they have been difficult to study in vitro. We have taken advantage of mice transgenic for the V beta 3/V alpha 11 T cell receptor (TCR), which can recognize a peptide of cytochrome c presented by IEk. 85-90% of CD4+ T cells in these mice express the transgenic TCR, and we show that almost all such V beta 3/V alpha 11 receptor-positive cells have a phenotype characteristic of naive T cells, including expression of high levels of CD45RB, high levels of L-selectin (Mel-14), low levels of CD44 (Pgp-1), and secretion of interleukin 2 (IL-2) as the major cytokine. Naive T cells, separated on the basis of CD45RB high expression, gave vigorous responses (proliferation and IL-2 secretion) to peptide antigen presented in vitro by a mixed antigen-presenting cell population. At least 50% of the T cell population appeared to respond, as assessed by blast transformation, entry into G1, and expression of increased levels of CD44 by 24 h. Significant contributions to the response by contaminating memory CD4+ cells were ruled out by demonstrating that the majority of the CD45RB low, L-selectin low, CD44 high cells did not express the V beta 3/V alpha 11 TCR and responded poorly to antigen. We find that proliferation and IL-2 secretion of the naive CD4 cells is minimal when resting B cells present peptide antigen, and that both splenic and bone marrow-derived macrophages are weak stimulators. Naive T cells did respond well to high numbers of activated B cells. However, dendritic cells were the most potent stimulators of proliferation and IL-2 secretion at low cell numbers, and were far superior inducers of IL-2 at higher numbers. These studies establish that naive CD4 T cells can respond vigorously to soluble antigen and indicate that maximal stimulation can be achieved by presentation of antigen on dendritic cells. This model should prove very useful in further investigations of activation requirements and functional characteristics of naive helper T cells.

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