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1.
Bardos T Czipri M Vermes C Finnegan A Mikecz K Zhang J 《Arthritis research & therapy》2003,5(2):R106-R113
Accumulating evidence suggests that regulatory T cells play a crucial role in preventing autoimmunity. Recently, a naturally
occurring CD4+CD25+ T-cell subset that is anergic and also suppressive has been shown to suppress autoimmunity in several animal models. We used
proteoglycan-induced arthritis (PGIA) as a study model to investigate the role of the CD4+CD25+ regulatory T cells in autoimmune arthritis. There was no significant change in the percentage of CD4+CD25+ T cells during the immunization period when proteoglycan- or ovalbumin-immunized BALB/c and C57BL/6 mice were compared. An
adoptive transfer study showed that the CD4+CD25+ T cells did not protect severe combined immunodeficient mice from arthritis when they were cotransferred with splenocytes
from arthritic animals. Similarly, depletion of the CD4+CD25+ T cells did not enhance the onset of the disease or disease severity in severe combined immunodeficient mice. Moreover, CD28-deficient
mice, which have very few CD4+CD25+ T cells, were highly resistant to PGIA. These findings indicate that the CD4+CD25+ regulatory T cells may not play a critical role in controlling PGIA. 相似文献
2.
Haibo Xue Weiwei Wang Zhongyan Shan Yuanbin Li Yushu Li Xiaochun Teng Yun Gao Chenling Fan Weiping Teng 《Biological trace element research》2011,143(1):292-301
Iodine is an essential trace element for thyroid hormone synthesis and metabolism, either low or high intake may lead to thyroid
disease, but the pathogenetic mechanisms by which iodine interacts with the thyroid autoimmune are poorly understood. We investigated
the dynamic changes of CD4+CD25+ regulatory T cells in NOD.H-2h4 mice with iodine-induced autoimmune thyroiditis (AIT), and explore potential immune mechanism of AIT induced by iodine. NOD.H-2h4 mice were randomly divided into two groups, and received plain water or water containing 0.005% sodium iodide. Eight weeks
after iodine provision, the incidences of thyroiditis, relative weights of thyroids, and serum thyroglobulin antibody titers
in the iodine-supplied groups were significantly increased compared to the control groups (p < 0.05). The AIT mice had fewer CD4+CD25+Foxp3+ T cells and reduced Foxp3 mRNA expression in splenocytes compared with the controls (p < 0.01), and maintained relatively low levels during the development of thyroiditis. The changes described above aggravated
gradually with the extension of iodine treatment. These data suggest that CD4+CD25+ regulatory T cells may be involved in the pathogenesis and development of AIT induced by iodine. 相似文献
3.
Zhi-Yong Xiao Shao-Hui Chen Jun-Ping Cheng Wen-Xia Zhou Yong-Xiang Zhang Ri-Fang Yang Liu-Hong Yun 《Arthritis research & therapy》2012,14(6):R235
Introduction
Naturally occurring CD4+CD25+ regulatory T (Treg) cells are central to the maintenance of peripheral tolerance. Impaired activity and/or a lower frequency of these cells lead to systemic lupus erythematosus (SLE). Manipulating the number or activity of Treg cells is to be a promising strategy in treating it and other autoimmune diseases. We have examined the effects of Y27, a novel derivative of 4-hydroxyquinoline-3-formamide, on SLE-like symptoms in MRL/lpr autoimmune mice and BDF1 hybrid mice. Whether the beneficial effect of Y27 involves modulation of CD4+CD25+ Treg cells has also been investigated.Methods
Female MRL/lpr mice that spontaneously develop lupus were treated orally by gavage with Y27 for 10 weeks, starting at 10 weeks of age. BDF1 mice developed a chronic graft-versus-host disease (GVHD) by two weekly intravenous injections of parental female DBA/2 splenic lymphocytes, characterized by immunocomplex-mediated glomerulonephritis resembling SLE. Y27 was administered to chronic GVHD mice for 12 weeks. Nephritic symptoms were monitored and the percentage of CD4+CD25+FoxP3+ Treg peripheral blood leukocyte was detected with mouse regulatory T cell staining kit by flowcytometry. Purified CD4+CD25+ Tregs were assessed for immune suppressive activity using the mixed lymphocyte reaction.Results
The life-span of MRL/lpr mice treated with Y27 for 10 weeks was significantly prolonged, proteinuria and renal lesion severity were ameliorated, and blood urea nitrogen, triglyceride and serum anti-double-stranded DNA antibodies were decreased. Similar results were found in chronic GVHD mice. Administration of Y27 had little impact on percentage of the peripheral blood lymphocyte CD4+CD25+Foxp3+ Treg cells in both groups of mice. In contrast, the suppressive capacity of CD4+CD25+ Treg cells in splenocytes was markedly augmented in Y27-treated mice ex vivo.Conclusions
Experimental evidence of the protect effects of Y27 against autoimmune nephritis has been shown. The mechanism may involve enhancement of the suppressive capacity of CD4+CD25+ Treg cells. 相似文献4.
Kazue Kogina Hirofumi Shoda Yumi Yamaguchi Nelson H. Tsuno Koki Takahashi Keishi Fujio Kazuhiko Yamamoto 《Molecules and cells》2009,28(2):125-130
Tacrolimus is a widely used T cell targeted immunosuppressive drug, known as a calcineurin inhibitor. However, the exact pharmacological
effects of tacrolimus on CD4+ T cells have yet to be elucidated. This study investigated the effects of tacrolimus on CD4+ T cell subsets. Mouse or human CD4+ T cells were cultured with immobilized anti-CD3/CD28 antibodies in the presence of tacrolimus. The cell division of CD4+ T cells was analyzed using a flow cytometer according to the expression of Foxp3. The gene expression patterns of tacrolimus-exposed
T cells were examined by quantitative PCR. In the case of conventional CD4+ T cells (Tconv cells), tacrolimus inhibited T cell receptor stimulation-induced cell division. In contrast, the cell division
of regulatory CD4+ T cells (Treg cells) was even promoted in the presence of tacrolimus, especially in humans. Tacrolimus did not promote conversion
of Tconv to Treg cells in mice. Furthermore, tacrolimus modified the expression levels of Foxp3-regulated T cell receptor
signal related-genes, PTPN22 and Itk, in human Treg cells. Immunosuppressive effect of tacrolimus may be attributed to the
relatively enhanced proliferation of Treg cells in association with altered gene expression levels of TCR signaling molecules. 相似文献
5.
CD4+CD25+Foxp3+ regulatory T (Treg) cells are believed to play an important role in suppressing autoimmunity and maintaining peripheral tolerance. How their survival is regulated in the periphery is less clear. Here we show that Treg cells express receptors for gamma chain cytokines and are dependent on an exogenous supply of these cytokines to overcome cytokine withdrawal apoptosis in vitro. This result was validated in vivo by the accumulation of Treg cells in Bim-/- and Bcl-2 tg mice which have arrested cytokine deprivation apoptosis. We also found that CD25 and Foxp3 expression were down-regulated in the absence of these cytokines. CD25+ cells from Scurfy mice do not depend on cytokines for survival demonstrating that Foxp3 increases their dependence on cytokines by suppressing cytokine production in Treg cells. Our study reveals that the survival of Treg cells is strictly dependent on cytokines and cytokine producing cells because they do not produce cytokines. Our study thus, demonstrates that different gamma chain cytokines regulate Treg homeostasis in the periphery by differentially regulating survival and proliferation. These findings may shed light on ways to manipulate Treg cells that could be utilized for their therapeutic applications. 相似文献
6.
David A Horwitz 《Arthritis research & therapy》2010,12(1):101
Various abnormalities in CD4+CD25+ regulatory T cells (Tregs) in systemic lupus erythematosus (SLE) include increased Foxp3+ cells that are CD25 negative. Barring methodological technical factors, these cells could be atypical Tregs or activated
non-Treg CD4+ cells that express Foxp3. Two groups have reached opposite conclusions that could possibly reflect the subjects studied.
One group studied untreated new-onset SLE and suggested that these T cells were mostly CD25-Foxp3+ non-Tregs. The other group studied patients with long-standing disease and suggested that these cells are mostly dysfunctional
Tregs. A third group reported increased Foxp3+CD4+CD25dim rather than CD25- cells in active SLE and these were also non-Tregs. Thus, it is likely that not all Foxp3+ T cells in SLE have protective suppressive activity. 相似文献
7.
Wölfl M Merker K Morbach H Van Gool SW Eyrich M Greenberg PD Schlegel PG 《Cancer immunology, immunotherapy : CII》2011,60(2):173-186
T cell-mediated immunotherapy against malignancies has been shown to be effective for certain types of cancer. However, ex vivo expansion of tumor-reactive T cells has been hindered by the low precursor frequency of such cells, often requiring multiple rounds of stimulation, resulting in full differentiation, loss of homing receptors and potential exhaustion of the expanded T cells. Here, we show that when using highly purified naïve CD8+ T cells, a single stimulation with peptide-pulsed, IFNγ/LPS-matured dendritic cells in combination with the sequential use of IL-21, IL-7 and IL-15 is sufficient for extensive expansion of antigen-specific T cells. Short-term expanded T cells were tumor-reactive, multifunctional and retained a central-memory-like phenotype (CD62L+, CCR7+, CD28+). The procedure is highly reproducible and robust as demonstrated for different healthy donors and for cancer patients. Such short-term tumor-antigen-primed, multifunctional T cells may therefore serve as a platform to target different malignancies accessible to immunotherapy. 相似文献
8.
Cao D van Vollenhoven R Klareskog L Trollmo C Malmström V 《Arthritis research & therapy》2004,6(4):R335-R346
CD25+CD4+ regulatory T cells participate in the regulation of immune responses. We recently demonstrated the presence of CD25brightCD4+ regulatory T cells with a capacity to control T cell proliferation in the joints of patients with rheumatoid arthritis. Here,
we investigate a possible accumulation of these regulatory T cells in the inflamed joint of different rheumatic diseases including
rheumatoid arthritis. The studies are also extended to analyze whether cytokine production can be suppressed by the regulatory
T cells. Synovial fluid and peripheral blood samples were obtained during relapse from 36 patients with spondyloarthropathies,
21 adults with juvenile idiopathic arthritis and 135 patients with rheumatoid arthritis, and the frequency of CD25brightCD4+ T cells was determined. Of 192 patients, 182 demonstrated a higher frequency of CD25brightCD4+ T cells in synovial fluid than in peripheral blood. In comparison with healthy subjects, the patients had significantly fewer
CD25brightCD4+ T cells in peripheral blood. For functional studies, synovial fluid cells from eight patients were sorted by flow cytometry,
and the suppressive capacity of the CD25brightCD4+ T cells was determined in in vitro cocultures. The CD25brightCD4+ T cells suppressed the production of both type 1 and 2 cytokines including interleukin-17, as well as proliferation, independently
of diagnosis. Thus, irrespective of the inflammatory joint disease investigated, CD25brightCD4+ T cells were reduced in peripheral blood and enriched in the joint, suggesting an active recruitment of regulatory T cells
to the affected joint. Their capacity to suppress both proliferation and cytokine secretion might contribute to a dampening
of local inflammatory processes. 相似文献
9.
Targeting interleukin-2 (IL-2) and/or agonist anti-CD40 antibody (Ab) into tumors represents an effective vaccination strategy
that avoids systemic toxicity and resolves treated-site tumors. Here, we examined IL-2 and/or anti-CD40 Ab-driven local versus
systemic T cell function and the installation of T cell memory. Single tumor studies showed that IL-2 induced a potent CD4+ and CD8+ T cell response that was limited to the draining lymph node and treated-site tumor, and lymph node tumor-specific CD8+ T cells did not upregulate CD44. A two-tumor model showed that while IL-2-treated-site tumors resolved, distal tumors continued
to grow, implying limited systemic immunity. In contrast, anti-CD40 Ab treatment with or without IL-2 expanded the systemic
T cell response to non-draining lymph nodes, and distal tumors resolved. Tumor-specific T cells in lymph nodes of anti-CD40
Ab ± IL-2-treated mice upregulated CD44, demonstrating activation and transition to effector/memory migratory cells. While
CD40-activated CD4+ T cells were not required for eradicating treated-site tumors, they, plus CD8+ T cells, were crucial for removing distal tumors. Rechallenge/depletion experiments showed that the effector/memory phase
required the presence of previously CD40/IL-2-activated CD4+ and CD8+ T cells to prevent recurrence. These novel findings show that different T cell effector mechanisms can operate for the eradication
of local treated-site tumors versus untreated distal tumors and that signaling through CD40 generates a whole of body, effector/memory
CD4+ and CD8+ T cell response that is amplified and prolonged via IL-2. Thus, successful immunotherapy needs to generate collaborating
CD4+ and CD8+ T cells for a complete long-term protective cure. 相似文献
10.
11.
Kenji Hiromatsu Jun Usami Yoshiyasu Aoki Masahiko Makino Yasunobu Yoshikai 《Microbiology and immunology》1997,41(3):221-227
We reported previously that CD4+ T cells and B cells in mice with retrovirus-induced murine acquired immunodeficiency syndrome (MAIDS) caused by LP-BM5 murine leukemia virus (MuLV) mixtures increased the expression of Fas antigen (Fas) during progression of the disease. However, the contribution of the Fas/Fas ligand (Fas L) system to the pathogenesis of MAIDS remained unknown. Here, we examined the susceptibility of C57BL/6 (B6) lpr/lpr mice, which has been reported to be defective for the expression of Fas, to MAIDS. We found that the Thy 1.2? CD4 T cells and IgK dull B220+ cells, which are characteristic of MAIDS, increased after the inoculation of LP-BM5 MuLV in B6 lpr/lpr mice. B22+ TCR αβ T cells, unique to lupus prone mice, also increased in the B6 lpr/lpr mice after infection. CD4+ B220+ TCR αβ T cells increased profoundly among the B220+ TCR αβ T cells from LP-BM5 MuLV-infected B6 lpr/lpr mice, while the B220+ TCR αβ T cells observed in non-infected B6 lpr/lpr mice were largely of the CD4? CD8? phenotype. A DNA PCR analysis of the LP-BM5 MuLV-infected B6 lpr/lpr mice revealed the genome integration of defective LP-BM5 virus, further confirming that MAIDS is inducible to B6 lpr/lpr mice. LP-BM5 MuLV-infected lpr/lpr mice died within 3 months, while MAIDS-infected B6 +/+ mice usually died within 5 to 6 months, and B6 lpr/lpr mice not infected with LP-BM5 MuLV lived more than 6 months. Taken together, these results suggest that MAIDS is inducible independently with functional Fas expression and the possibility of accelerated progression of murine AIDS and lpr-associated autoimmune disease in B6 lpr/lpr mice infected with LP-BM5 MuLV. 相似文献
12.
13.
Pawlik A Ostanek L Brzosko I Brzosko M Masiuk M Machalinski B Gawronska-Szklarz B 《Arthritis research & therapy》2003,5(4):R210-R213
Clonal expansion of CD4+CD28- T cells is a characteristic finding in patients with rheumatoid arthritis (RA). Expanded CD4+ clonotypes are present in the peripheral blood, infiltrate into the joints, and persist for years. CD4+CD28- T cells are oligoclonal lymphocytes that are rare in healthy individuals but are found in high percentages in patients with
chronic inflammatory diseases. The size of the peripheral blood CD4+CD28- T-cell compartment was determined in 42 patients with RA and 24 healthy subjects by two-color FACS analysis. The frequency
of CD4+CD28- T cells was significantly higher in RA patients than in healthy subjects. Additionally, the number of these cells was significantly
higher in patients with extra-articular manifestations and advanced joint destruction than in patients with limited joint
manifestations. The results suggest that the frequency of CD4+CD28- T cells may be a marker correlating with extra-articular manifestations and joint involvement. 相似文献
14.
Lundin KU Screpanti V Omholt H Hofgaard PO Yagita H Grandien A Bogen B 《Cancer immunology, immunotherapy : CII》2004,53(12):1135-1145
B-lymphoma cells express a highly tumor-specific antigen, monoclonal Ig, which is a promising target for immunotherapy. Previous work has demonstrated that B-lymphoma cells spontaneously process their endogenous monoclonal Ig and present variable (V) region peptides (Id-peptides) on their MHC class II molecules to CD4+ T cells. Id-specific CD4+ T cells protect mice against B-lymphoma cells in the absence of anti-idiotypic antibodies. The molecular mechanism by which Id-specific CD4+ T cells kill B-lymphoma cells is hitherto unknown. We here demonstrate in an Id-specific T-cell receptor (TCR)–transgenic mouse model that Id-specific CD4+ T cells induce apoptosis of Fas+ B-lymphoma cells in vitro by FasLigand (FasL)–Fas interaction. Moreover, the rare B lymphomas that had escaped rejection in TCR-transgenic mice had down-regulated their sensitivity to Fas-mediated apoptosis. Although these results suggest that FasL-Fas interaction is important, Id-specific CD4+ T cells could eliminate Id+ B-lymphoma cells in vivo by other mechanisms, since three independent ways of blocking FasL-Fas–mediated killing failed to abrogate tumor protection in TCR-transgenic mice. These results suggest that there are several redundant pathways by which Id-specific CD4+ T cells eliminate Id+ B-lymphoma cells in vivo, of which FasL-Fas interaction is only one.Supported by grants from the Norwegian Cancer Society, the Research Council of Norway, and the Multiple Myeloma Research Foundation. 相似文献
15.
Molhoek KR McSkimming CC Olson WC Brautigan DL Slingluff CL 《Cancer immunology, immunotherapy : CII》2009,58(6):867-876
Targeted molecular therapies inhibit proliferation and survival of cancer cells but may also affect immune cells. We have
evaluated the effects of Sirolimus and Sorafenib on proliferation and survival of lymphoid cell subsets. Both drugs were cytotoxic
to CD4+CD25high T cells, and were growth inhibitory for CD4+ and CD8+ T cells. Cytotoxicity depended on CD3/CD28 stimulation and was detectable within 12 h, with 80–90% of CD4+CD25high cells killed by 72 h. Cell death was due to apoptosis, based on Annexin V and 7AAD staining. Addition of IL-2 prevented the
apoptotic response to Sirolimus, potentially accounting for reports that Sirolimus can enhance proliferation of CD4+CD25high cells. These results predict that Sirolimus or Sorafenib would reduce CD4+CD25high cells if administered prior to antigenic stimulation in an immunotherapy protocol. However, administration of IL-2 protects
CD4+CD25high T cells from cytotoxic effects of Sirolimus, a response that may be considered in design of therapeutic protocols. 相似文献
16.
Boot EP Koning GA Storm G Wagenaar-Hilbers JP van Eden W Everse LA Wauben MH 《Arthritis research & therapy》2005,7(3):R604-R615
T cells have an important role during the development of autoimmune diseases. In adjuvant arthritis, a model for rheumatoid
arthritis, we found that the percentage of CD4+ T cells expressing the activation marker CD134 (OX40 antigen) was elevated before disease onset. Moreover, these CD134+ T cells showed a specific proliferative response to the disease-associated epitope of mycobacterial heat shock protein 60,
indicating that this subset contains auto-aggressive T cells. We studied the usefulness of CD134 as a molecular target for
immune intervention in arthritis by using liposomes coated with a CD134-directed monoclonal antibody as a drug targeting system.
Injection of anti-CD134 liposomes subcutaneously in the hind paws of pre-arthritic rats resulted in targeting of the majority
of CD4+CD134+ T cells in the popliteal lymph nodes. Furthermore, we showed that anti-CD134 liposomes bound to activated T cells were not
internalized. However, drug delivery by these liposomes could be established by loading anti-CD134 liposomes with the dipalmitate-derivatized
cytostatic agent 5'-fluorodeoxyuridine. These liposomes specifically inhibited the proliferation of activated CD134+ T cells in vitro, and treatment with anti-CD134 liposomes containing 5'-fluorodeoxyuridine resulted in the amelioration of adjuvant arthritis.
Thus, CD134 can be used as a marker for auto-aggressive CD4+ T cells early in arthritis, and specific liposomal targeting of drugs to these cells via CD134 can be employed to downregulate
disease development. 相似文献
17.
Bettahi I Dasgupta G Renaudet O Chentoufi AA Zhang X Carpenter D Yoon S Dumy P BenMohamed L 《Cancer immunology, immunotherapy : CII》2009,58(2):187-200
Molecularly defined synthetic vaccines capable of inducing both antibodies and cellular anti-tumor immune responses, in a
manner compatible with human delivery, are limited. Few molecules achieve this target without utilizing external immuno-adjuvants.
In this study, we explored a self-adjuvanting glyco-lipopeptide (GLP) as a platform for cancer vaccines using as a model MO5,
an OVA-expressing mouse B16 melanoma. A prototype B and T cell epitope-based GLP molecule was constructed by synthesizing
a chimeric peptide made of a CD8+ T cell epitope, from ovalbumin (OVA257–264) and an universal CD4+ T helper (Th) epitope (PADRE). The resulting CTL–Th peptide backbones was coupled to a carbohydrate B cell epitope based
on a regioselectively addressable functionalized templates (RAFT), made of four α-GalNAc molecules at C-terminal. The N terminus
of the resulting glycopeptides (GP) was then linked to a palmitic acid moiety (PAM), obviating the need for potentially toxic
external immuno-adjuvants. The final prototype OVA-GLP molecule, delivered in adjuvant-free PBS, in mice induced: (1) robust
RAFT-specific IgG/IgM that recognized tumor cell lines; (2) local and systemic OVA257–264-specific IFN-γ producing CD8+ T cells; (3) PADRE-specific CD4+ T cells; (4) OVA-GLP vaccination elicited a reduction of tumor size in mice inoculated with syngeneic murine MO5 carcinoma
cells and a protection from lethal carcinoma cell challenge; (5) finally, OVA-GLP immunization significantly inhibited the
growth of pre-established MO5 tumors. Our results suggest self-adjuvanting glyco-lipopeptide molecules as a platform for B
Cell, CD4+, and CD8+ T cell epitopes-based immunotherapeutic cancer vaccines.
Both I. Bettahi and G. Dasgupta have contributed equally to this work. 相似文献
18.
Elkord E Burt DJ Drijfhout JW Hawkins RE Stern PL 《Cancer immunology, immunotherapy : CII》2008,57(6):833-847
Background The human 5T4 (h5T4) oncofoetal antigen is expressed by a wide variety of human carcinomas including colorectal, ovarian,
gastric and renal, but rarely on normal tissues. Its restricted expression on tumour tissues as well as its association with
tumour progression and bad prognosis has driven the development of a MVA-based vaccine (TroVax) which has been tested in several
early phase clinical trials and these studies have led to the start of a phase III trial in renal cell carcinoma patients.
We have recently shown that CD8+ T cells recognizing h5T4 can be generated in the absence of CD4+ T cells from peripheral blood lymphocytes of human healthy individuals.
Results We report the existence and expansion of human CD4+ T cells against h5T4 by stimulation with autologous monocyte-derived dendritic cells infected with a replication defective
adenovirus encoding the h5T4 cDNA (Ad-h5T4). The h5T4-specific T-cell responses in normal individuals are enhanced by initial
depletion of CD25+ cells (putative T regulatory cells) prior to the in vitro stimulation. We have identified a novel h5T4-derived 15-mer peptide
recognized by CD4+ T cells in HLA-DR4 positive healthy individuals. Interestingly, CD4+ T cells spontaneously recognizing a different 5T4 epitope restricted by HLA-DR were identified in tumour-infiltrating lymphocytes
isolated from a regressing renal cell carcinoma lung metastasis.
Conclusion Our data show that CD4+ T cells recognizing h5T4 can be expanded and detected in healthy individuals and a renal cell carcinoma patient. Such h5T4-specific
CD4+ T cells boosted or induced by vaccination could act to modulate both cell or antibody mediated anti-tumour responses.
This work was supported by Cancer Research UK. 相似文献
19.
Frey O Petrow PK Gajda M Siegmund K Huehn J Scheffold A Hamann A Radbruch A Bräuer R 《Arthritis research & therapy》2005,7(2):R291-R301
It is now generally accepted that CD4+CD25+ Treg cells play a major role in the prevention of autoimmunity and pathological immune responses. Their involvement in the pathogenesis
of chronic arthritis is controversial, however, and so we examined their role in experimental antigen-induced arthritis in
mice. Depletion of CD25-expressing cells in immunized animals before arthritis induction led to increased cellular and humoral
immune responses to the inducing antigen (methylated bovine serum albumin; mBSA) and autoantigens, and to an exacerbation
of arthritis, as indicated by clinical (knee joint swelling) and histological scores. Transfer of CD4+CD25+ cells into immunized mice at the time of induction of antigen-induced arthritis decreased the severity of disease but was
not able to cure established arthritis. No significant changes in mBSA-specific immune responses were detected. In vivo migration studies showed a preferential accumulation of CD4+CD25+ cells in the inflamed joint as compared with CD4+CD25- cells. These data imply a significant role for CD4+CD25+ Treg cells in the control of chronic arthritis. However, transferred Treg cells appear to be unable to counteract established acute or chronic inflammation. This is of considerable importance for
the timing of Treg cell transfer in potential therapeutic applications. 相似文献
20.
Resting naive CD4+CD45R0?CD45RA+ T cells are sensitive to ionomycin. In contrast, resting CD4+CD45RA?CD45R0+ memory T cells show resistance to this Ca2+ ionophore. In the present study, the ability of activated T lymphocytes to respond to ionomycin during the transition from naive precursors into memory T cells has been analyzed. Activated CD4+CD45RA+CD45R0+ T cells are always present both in human peripheral blood (HPB) and in the ionomycin-resistant (IR) fraction. Therefore, some activated T cells are resistant toward the Ca2+ ionophore. CD69 molecules are markers of the very early stage of T cell activation. However, CD4+CD69+ T cells have never been found in the IR fraction. Thus, the majority of CD4+ T lymphocytes at the early stage of activation are ionomycin-sensitive cells. The proportion of CD4+CD25+ T cells did not differ significantly in HPB and in the IR fraction. The presence of CD4+CD25+ T lymphocytes in the IR fraction reflects changes in the Ca2+-signaling pathway at this differentiation step of activated cells. Depending on the expression level of CD25 molecules, the population of CD4+CD25+ cells is divided in T-regulatory (CD25high) and proliferating (CD25low) subpopulations. The action of ionomycin results in a decrease in the portion of the CD4+CD25low T-cells, but it leads to an increase in the proportion of the CD4+CD25high T lymphocytes. Consequently, greater portion of CD4+CD25high T lymphocytes and smaller portion of CD4+CD25low T cells are IR cells. Expression of HLA-DR molecules can be used as the marker for the late activation step. The IR fraction is significantly rich in CD4+HLA-DR+ T lymphocytes in comparison to the blood of the same donor. The link between different differentiation steps of CD4+ T-lymphocytes and alterations in calcium ion homeostasis is discussed. 相似文献