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Previous studies have shown that under normal physiological conditions thymic B cells play a critical function in T cell negative selection. We tested the effect of thymic B cells on thymic T-cell differentiation in autoimmune diseases including systemic lupus erythematosus (SLE). We found that thymic B cells and CD8 - CD4 + and CD4 - CD8 + T cells increased, whereas CD4 + CD8 + T cells decreased in lupus-prone mice. Once B cells were reduced, the change was reversed. Furthermore, we found that B cells blocked thymic immature single positive (ISP) CD4 - CD8 + CD3 lo/- RORγt - T cells progression into CD4 + CD8 + T cells. Interestingly, we found a novel population of thymic immature T cells (CD4 - CD8 + CD3 lo RORγt + ) that were induced into mature CD4 - CD8 + CD3 + RORγt + T cells by B cells in lupus-prone mice. Importantly, we found that IgG, produced by thymic B cells, played a critical role in the differentiation of thymic CD8 + ISP and mature RORγt + CD8 + T cells in lupus-prone mice. In conclusion, B cells blocked the differentiation from thymic CD8 + ISP and induced the differentiation of a novel immature CD4 - CD8 + CD3 lo RORγt + T cells into mature RORγt + CD8 + T cells by secreting IgG antibody in lupus-prone mice., Competing Interests: CONFLICTS OF INTEREST The authors declare no commercial or financial conflict of interest.

B cell activating factor (BAFF) regulates B cell maturation, survival, function, and plays a critical pathogenic role in autoimmune diseases. It remains unclear how BAFF affects IL-10 - B cells versus regulatory B cells (Bregs) in inflammatory responses. In this study, we found that IL-10-expressing Bregs decreased in lupus-prone MRL/lpr mice and experimental allergic encephalomyelitis (EAE) mice. On blockade of the effects of BAFF with TACI-IgG, IL-10 + Bregs were upregulated in MRL/lpr and EAE mice. In addition, BAFF expanded IL-10 + B cells over IL-10 - B cells under noninflammatory conditions in vitro, whereas it expanded IL-10 - B cells over IL-10 + B cells during inflammatory responses, such as stimulation with autoantigen and LPS. Finally, the selection of IL-10 - B cells over IL-10 + B cells by BAFF was dependent on BAFF receptors (BAFFR, TACI, and BCMA) that were upregulated by inflammatory responses. This study suggests that BAFF selects IL-10 - B cells over IL-10 + regulatory B cells via BAFF receptors in inflammatory responses., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Interleukin 10 (IL-10)-producing regulatory B-cells (Bregs) suppress inflammatory responses that mediate autoimmune diseases. However, it is unknown whether Bregs derive from a pre-existing dedicated B-cell lineage or if any B-cell can differentiate into Bregs in response to BCR or TLR activation. GL7(+) B-cells are antigen-experienced differentiated B-cells while GL7(-/lo) are at an early stage of B-cell differentiation. While both GL7(-/lo) and GL7(+) B cells can produce IL-10, differentiation of GL7(-) B-cells into Bregs does not require CD19- or Bcl6-induced signals, suggesting that BCR-induced proliferation or Ig class-switching is not necessary for generation of Breg cells. Of particular importance, we show that GL7(-) Breg cells are dramatically expanded in lupus-like mice and GL7(-) Bregs suppressed inflammatory responses in lupus-like mice by inducing expansion of Foxp3(+)Treg cells. Taken together, these results suggest that pre-existing GL7(-)IL-10(+) cells are expanded during inflammation, differentiate into GL7(+) Bregs and contribute to immune-regulation in lupus-like mice., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

Rickettsia heilongjiangensis is the pathogen of Far eastern spotted fever, and T-cell immunoglobulin and mucin domain protein 3 (Tim-3) is expressed in human vascular endothelial cells, the major target cells of rickettsiae. In the present study, we investigated the effects of altered Tim-3 expression in vivo in mice and in vitro in human endothelial cells, on day 3 after R. heilongjiangensis infection. Compared with corresponding controls, rickettsial burdens both in vivo and in vitro were significantly higher with blocked Tim-3 signaling or silenced Tim-3 and significantly lower with overexpressed Tim-3. Additionally, the expression of inducible nitric oxide synthase and interferon γ in endothelial cells with blocked Tim-3 signaling or silenced Tim-3 was significantly lower, while the expression of inducible nitric oxide synthase, interferon γ, and tumor necrosis factor α in transgenic mice with Tim-3 overexpression was significantly higher. These results reveal that enhanced Tim-3 expression facilitates intracellular rickettsial killing in a nitric oxide-dependent manner in endothelial cells during the early phase of rickettsial infection., (© The Author 2015. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.)

Tim-3 is involved in the physiopathology of inflammatory bowel disease (IBD), but the underlying mechanism is unknown. Here, we demonstrated that, in mouse with DSS colitis, Tim-3 inhibited the polarization of pathogenic pro-inflammatory M1 macrophages, while Tim-3 downregulation or blockade resulted in an increased M1 response. Adoptive transfer of Tim-3-silenced macrophages worsened DSS colitis and enhanced inflammation, while Tim-3 overexpression attenuated DSS colitis by decreasing the M1 macrophage response. Co-culture of Tim-3-overexpressing macrophages with intestinal lymphocytes decreased the pro-inflammatory response. Tim-3 shaped intestinal macrophage polarization may be TLR-4 dependent since Tim-3 blockade failed to exacerbate colitis or increase M1 macrophage response in the TLR-4 KO model. Finally, Tim-3 signaling inhibited phosphorylation of IRF3, a TLR-4 downstream transcriptional factor regulating macrophage polarization. A better understanding of this pathway may shed new light on colitis pathogenesis and result in a new therapeutic strategy., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Recently B-cell activating factor (BAFF) was identified by our group and others as a novel therapeutic target for the treatment of autoimmune diseases. To expand upon this, we utilized microarrays to screen for molecules upregulated in B cells from BAFF-inhibited mice with lupus-like disease and identified metabotropic glutamate receptor 3 (Grm3). In addition to confirming the expression of this receptor in B cells, a synthetic agonist of Grm3 was found to downregulate B cells and ameliorate autoimmune symptoms in mice. Conversely, a Grm3 antagonist increased B-cell numbers and further aggravated disease. Thus, these results suggest that activation of Grm3 ameliorates lupus-like disease in mice by reducing B cell numbers. Not only do the findings presented in this study increase our understanding of the inhibitory signals initiated on the surface of B cells, but they also identify a novel potential target for the treatment of autoimmune diseases., (Copyright © 2015 Elsevier Inc. All rights reserved.)

This study tested the hypothesis that besides the spleen, LNs, peripheral blood, and thymus contain a regulatory IL-10-producing CD19(+)CD5(+)CD1d(high) B cell subset that may play a critical role in the maintenance of immune homeostasis. Indeed, this population was identified in the murine thymus, and furthermore, when cocultured with CD4(+) T cells, this population of B cells supported the maintenance of CD4(+)Foxp3(+) Tregs in vitro, in part, via the CD5-CD72 interaction. Mice homozygous for Cd19(Cre) (CD19(-/-)) express B cells with impaired signaling and humoral responses. Strikingly, CD19(-/-) mice produce fewer CD4(+)Foxp3(+) Tregs and a greater percentage of CD4(+)CD8(-) and CD4(-)CD8(+) T cells. Consistent with these results, transfer of thymic CD19(+)CD5(+)CD1d(hi) B cells into CD19(-/-) mice resulted in significantly up-regulated numbers of CD4(+)Foxp3(+) Tregs with a concomitant reduction in CD4(+)CD8(-) and CD4(-)CD8(+) T cell populations in the thymus, spleen, and LNs but not in the BM of recipient mice. In addition, thymic CD19(+)CD5(+)CD1d(hi) B cells significantly suppressed autoimmune responses in lupus-like mice via up-regulation of CD4(+)Foxp3(+) Tregs and IL-10-producing Bregs. This study suggests that thymic CD19(+)CD5(+)CD1d(hi)IL-10(+) Bregs play a critical role in the maintenance of immune homeostasis., (© Society for Leukocyte Biology.)

Mounting evidence has suggested that inflammation associated with interleukin (IL)‑6 and T‑helper (Th)17 cells, has a role in the development of atherosclerotic cerebral infarction (ACI). However, it remains unclear which population of cells determines the levels of IL‑6, and the role of IL‑6‑secreting cells in inducing Th17 cell production. In the present study, IL‑6 levels were determined in patients with ACI, by ELISA. The percentage of CD3+T, CD4+T, CD8+T, CD11c+ dendritic cells and γδT cells were determined by flow cytometry, and the correlation between cytokine IL‑6 and γδT cells was determined by statistical analysis. An in vitro culture assay was used to determine whether γδT cells secreted high levels of IL‑6, and induced production of Th17 cells. The patients with ACI had significantly higher levels of IL‑6 and γδT cells. Furthermore, γδT cells were associated with the secretion of a high level of IL‑6 in patients with ACI. These results indicate that γδT cells are novel IL‑6‑secreting cells, which from then on were known as γδT6 cells. In addition, the novel γδT6 cells induced Th17‑cell production, and this induction was dependent on IL‑6. Novel γδT6 cells increased the induction of Th17‑cell production in patients with ACI. The results of the present study suggest that novel γδT6 cells may be a target for strategic therapies of ACI.

Circulating lymphocyte number was significantly decreased in patients with sepsis. However, it remains unknown which severity phase (sepsis, severe sepsis, and septic shock) does it develop and what happen on each subpopulation. Eight patients with differing severities of sepsis (31 sepses, 33 severe sepses, and 16 septic shocks) were enrolled. Quantitative real-time polymerase chain reaction (RT-PCR) of Th1, Th2, and Th17; regulatory T (Treg) cell-specific transcription factor T-bet; GATA-3; RORgammat (RORγt); forkhead box P3 (FOXP3); and IL-17 mRNA were performed, and the enzyme-linked immunosorbent assay (ELISA) was used to detect serum interferon (IFN)-γ, IL-4, and IL-10. In this study, the Th1, Th2, Treg transcription factors, and related cytokines IFN-γ, IL-4, and IL-10 levels of sepsis and severe sepsis patients in peripheral blood were significantly higher than those of the normal controls. Except for IL-17, the T-bet, GATA-3, and IFN-γ levels of septic shock patients were lower than those of sepsis patients. We also observed that the proportions of Th17/Treg in the sepsis and septic shock groups were inversed. From the above, the inflammatory response especially the adaptive immune response is still activated in sepsis and severe sepsis, but significant immunosuppression was developed in septic shock. In addition, the proportion of Th17/Treg inversed may be associated with the illness aggravation of patients with sepsis.

Tumor necrosis factor-α (TNF-α) acts as a key factor for the development of inflammatory bowel diseases (IBDs), whose function is known to be mediated by TNF receptor 1 (TNFR1) or TNFR2. However, the precise role of the two receptors in IBD remains poorly understood. Herein, chronic colitis was established by oral administration of dextran sulfate sodium (DSS) in TNFR1 or TNFR2-/- mice. Unexpectedly, TNFR1 or TNFR2 deficiency led to exacerbation of signs of colitis compared with wild-type (WT) counterparts. Of note, TNFR1 ablation rendered significantly increased mortality compared with TNFR2 and WT mice after DSS. Aggravated pathology of colitis in TNFR1-/- or TNFR2-/- mice correlated with elevated colonic expression of proinflammatory cytokines and chemokines. Importantly, ablation of TNFR1 or TNFR2 increased apoptosis of colonic epithelial cells, which might be due to the heightened ratio of Bax/Bcl-2 and increased expression of caspase-8. Intriguingly, despite comparable intensity of intestinal inflammation in TNFR-deficient mice after DSS, systemic inflammatory response (including splenomegaly and myeloid expansion) was augmented dramatically in TNFR1-/- mice, instead of TNFR2-/- mice. Granulocyte-macrophage colony-stimulating factor (GMCSF) was identified as a key mediator in this process, as neutralization of GMCSF dampened peripheral inflammatory reaction and reduced mortality in TNFR1-/- mice. These data suggest that signaling via TNFR1 or TNFR2 has a protective role in chronic intestinal inflammation, and that lacking TNFR1 augments systemic inflammatory response in GMCSF-dependent manner.

Objective: It is well known that complement system C5a is excessively activated during the onset of sepsis. However, it is unclear whether C5a can regulate dentritic cells (DCs) to stimulate adaptive immune cells such as Th1 and Th17 in sepsis., Methods: Sepsis was induced by cecal ligation and puncture (CLP). CLP-induced sepsis was treated with anti-C5a or IL-12. IL-12(+)DC, IFNγ(+)Th1, and IL-17(+)Th17 cells were analyzed by flow cytometry. IL-12 was measured by ELISA., Results: Our studies here showed that C5a induced IL-12(+)DC cell migration from the peritoneal cavity to peripheral blood and lymph nodes. Furthermore, IL-12(+)DC cells induced the expansion of pathogenic IFNγ(+)Th1 and IL-17(+)Th17 cells in peripheral blood and lymph nodes. Moreover, IL-12, secreted by DC cells in the peritoneal cavity, is an important factor that prevents the development of sepsis., Conclusion: Our data suggests that C5a regulates IL-12(+)DC cell migration to induce pathogenic Th1 and Th17 cells in sepsis.

Complement represents a chief component of innate immunity in host defense. However, excessive complement activation has been involved in the pathogenesis of inflammatory diseases. In this study, we investigated the contribution of complement to intestinal pathology of patients and rodents with inflammatory bowel disease. The expression of complement effectors (C3a and C3) was increased remarkably in inflamed colons of IBD patients compared with those of normal counterparts. In accordance with this, the sustained activation of complement in serum and colon (including elevated C3a and C5a levels, enhanced hemolytic activity, downregulated expression of C5a receptors) was observed, following the establishment of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis, which peaked at 24 h. Mice pretreated with neutralizing anti-C5a antibodies (-2, 0, and 2 days after TNBS instillation) had significantly reduced weight loss and improved macroscopic/microscopic scores, comparable to the efficacy of prednisolone treatment. Strikingly, treatment with anti-C5a at 24 h after TNBS instillation showed remarkable therapeutic effects, whereas prednisolone did not. The efficacy of anti-C5a administration was associated with decreased release of proinflammatory chemokines and cytokines, inhibition of infiltration of neutrophils into colons, and enhanced Th2 response. These findings suggest a disease-promoting role of complement, particular C5a, in the pathology of TNBS-induced colitis in mice, indicating possible therapeutic potentials for C5a-specific antibody in IBD.

By binding to T cell Ig mucin-3 (Tim-3) expressed on different cells, galectin-9 (Gal-9) mediates two important functions, triggering T cell death and activating innate immune cells. The mechanisms by which ligation of the same molecule on different cell types mediates different effects are largely unclear. Gal-9 contains two carbohydrate recognition domains (CRD) in the N- and C-terminal regions (Gal-9-N and Gal-9-C). The N and C terminals of Gal-9 have been shown to have different activities in promoting T cell death. However, whether the differences between two domains account for its dual functions remains to be elucidated. Here we hypothesized that the different functions of Gal-9 in innate immunity and adaptive immunity are mediated by different domains. To test this, we created recombinant Gal-9 (Gal-9-NC) and homodimers containing either the NCRD (Gal-9-N) or the CCRD (Gal-9-C). All these Gal-9 constructs can activate dendritic cells (DCs) and induce T cell death. However, the Gal-9-C was much more potent than the Gal-9-N in inducing T cell death, while the Gal-9-N was much more effective in activating DCs by inducing much higher TNF-α and IL-6 production, greater phosphorylation of p38 and AKT. In both DC and T cells, Gal-9-N but not Gal-9-C stimulation resulted in markedly iκBα degradation. Finally, computer analyses suggested different patterns and affinities for the binding of the Gal-9-N and Gal-9-C to their receptor, Tim-3. Our data suggest that the N- and C-terminal CRDs of Gal-9 contribute differently to its ability to induce T cell death and to activate DCs. Further investigations on the underlying mechanisms will provide new insights into the biochemical basis for the multiple activities of Gal-9., (Copyright © 2010 Elsevier Ltd. All rights reserved.)

Complement 5a (C5a) and Interleukin-17 (IL-17) are two important inflammatory mediators in sepsis. Here we studied the mechanisms underlying regulation of IL-17 by anaphylatoxin C5a. We found that C5a blockade increased the survival rate of mice following cecal ligation and puncture (CLP)-induced sepsis and decreased IL-17 expression in vivo. IL-17 was secreted mainly by gammadelta T cells in this model. Importantly, our data suggest that C5a participates in the regulation of IL-17 secretion by gammadelta T cells. Dendritic cells (DC) were found to act as a "bridge" between C5a and gammadelta T cells in a mechanism involving IL-6 and transforming growth factor beta (TGF-beta). These results imply that C5a affects the crosstalk between DC and gammadelta T cells during sepsis development, and this may result in a large production of inflammatory mediators such as IL-17.

Whether interleukin (IL)-17 promotes a diabetogenic response remains unclear. Here we examined the effects of neutralization of IL-17 on the progress of adoptively transferred diabetes. IL-17-producing cells in non-obese diabetic (NOD) mice were identified and their role in the pathogenesis of diabetes examined using transfer and co-transfer assays. Unexpectedly, we found that in vivo neutralization of IL-17 did not protect NOD-severe combined immunodeficiency (SCID) mice against diabetes transferred by diabetic splenocytes. In NOD mice, gammadelta(+) T cells were dominated by IL-17-producing cells and were found to be the major source of IL-17. Interestingly, these IL-17-producing gammadelta T cells did not exacerbate diabetes in an adoptive transfer model, but had a regulatory effect, protecting NOD mice from diabetes by up-regulating transforming growth factor (TGF)-beta production. Our data suggest that the presence of IL-17 did not increase the chance of the development of diabetes; gammadelta T cells protected NOD mice from diabetes in a TGF-beta-dependent manner, irrespective of their role as major IL-17 producers.

Recently, the anti-CD3 antibody has been shown to be a promising candidate for the efficient treatment of overt autoimmunity. However, the mechanisms underlying this effect remain unclear. Our previous studies demonstrated that natural killer (NK)T cells and transforming growth factor (TGF)-beta were key elements in anti-CD3 F(ab')(2)-mediated re-establishment of glucose homeostasis and restoration of self tolerance to islets in type 1 diabetes. In this report, we further investigate the regulatory pathways involved, especially the cellular source of TGF-beta production. The treatment of new-onset nonobese diabetic mice with anti-CD3 F(ab')(2) resulted in a significant increase in the numbers of NK cells in spleen and pancreatic lymph nodes that secrete TGF-beta. Depletion of this cell population with a specific anti-AsGM1 antibody abrogated anti-CD3 F(ab')(2) therapeutic effects and splenic TGF-beta production. When fractionated from recovered mice after CD3 antibody therapy, these NK cells actively suppressed diabetogenic cell proliferation and prevented the cotransfer of diabetes into nonobese diabetic-severe combined immunodeficient mice in a TGF-beta-dependent manner. In addition, the regulatory NKT cells from remitting mice were capable of causing NK cells to exhibit a TGF-beta-producing phenotype by the secretion of the T helper 2 cytokines interleukins 4 and 10. Overall, these data indicate that NK cells are the main source of TGF-beta production after anti-CD3 F(ab')(2) treatment, which are controlled by a population of T helper 2-like NKT cells.

Anti-CD3 mAb have potentials to treat overt autoimmunity as reported recently. However, the underlying mechanisms remain unclear. In this report, using an animal model of type 1 diabetes, we found that TGF-beta1, an important immunoregulatory cytokine, plays a critical role in anti-CD3-mediated diabetes reversion and immune tolerance. Anti-CD3 treatment increased the TGF-beta1 production, lasting for a long period of time, which contributed to maintaining peripheral tolerance by controlling pathogenic cells. Furthermore, we found that anti-CD3 treatment did not increase the forkhead box p3+ (Foxp3+)CD4+ regulatory T cells (Tregs). When fractionated from anti-CD3-treated, remitting mice and cotransferred with splenic cells from diabetic NOD mice, these Tregs failed to inhibit diabetes development in NOD.scid mice. Moreover, we found that the depletion of these Tregs did not affect an anti-CD3-mediated, therapeutic effect and the level of TGF-beta1 production, which suggested that an increased level of TGF-beta1 may not derive from these Tregs. Thus, our data showed a dispensable role of Foxp3+CD4+ Tregs in anti-CD3 antibody-reversed diabetes in NOD mice. These findings may have an important implication for understanding the involved mechanisms responsible for immunomodulatory function of anti-CD3 antibody on autoimmune diseases.

We previously found that adeno-associated viral vector serotype 2 (AAV-2) muscle gene delivery of GAD 500-585 autoantigen efficiently prevented autoimmune diabetes in NOD mice. Recent reports suggest that AAV vectors based on serotype 1 (AAV-1) transduce murine skeletal muscle much more efficiently than AAV-2, with reported increases in expression ranging from 2 to 1000-fold. To determine whether this increased efficacy of AAV-1 could result in increased therapeutic effects in mice, we constructed rAAV1/GAD 500-585 vectors and compared their effects in preventing autoimmune diabetes in NOD mice with those of rAAV2/GAD 500-585 after muscle injection. rAAV(1)/GAD(500-585) gene therapy prevented diabetes in NOD mice. However, although much higher level of GAD 500-585 expression was found in mice using AAV-1 as gene delivery vector than those using AAV-2, no increased efficiency of AAV-1 vectors were found in their capability to prevent autoimmune diabetes, as higher titers of rAAV1/GAD 500-585 virus (3x10(11)v.g./mouse) were needed to obtain therapeutic effects in NOD mice, a titer not different from that of AAV-2. Protection resulted from rAAV1/GAD 500-585 gene therapy were marked by enhanced Th2 immune response and up-regulated CD4+ Foxp3+T regulatory cells, which might actively suppress effector T cells in NOD mice. As here we found that the therapeutic effects of AAV1 were not positively correlated to it's transduction efficiency, our data suggested that the safety and other factors besides efficiency should be considered when use different AAV serotype to treat autoimmune disease.

The complement C5 anaphylatoxin receptor is a member of the seven transmembrane-spanning G protein-coupled receptor superfamily that signals through Galphai and Galpha16. C5aR is mostly expressed on neutrophils, macrophages and endothelial cells. C5a and C5aR interaction plays an important role in numerous biological effects such as in vivo cytokine storm which results in inflammatory damage. Considering the limitation of collection of human peripheral blood neutrophils and their short half life, the stably transfected cell line for studying the biological effects of C5aR is needed. In this study, we transfected C5aR gene into Molt-4 cell line and examined the function of ectopic C5aR. Our results showed stable expression of the C5aR in Molt-4 cell line and their interaction with human C5a induced ERK1/2 phosphorylation, Ca++ influx. This stable transfected cell line may provide a useful tool for studying signal pathways related to C5a and C5aR interplay and antibody development specific for C5aR.

Purpose: The aims of this study were to determine whether IL-17(+) T cells were present in CD4 and CD8 interphotoreceptor retinoid-binding protein (IRBP)-specific T cells and to determine the role of antigen-specific and nonspecific IL-17(+) T cells in the pathogenesis of experimental autoimmune uveitis (EAU)., Methods: B6 mice were immunized with uveitogenic peptide IRBP1-20. In vivo-primed T cells were separated and stimulated with the immunizing peptide. Intracellular expression of IFN-gamma and IL-17 by the T cells was assessed, and the pathogenic activity of the activated T cells was determined., Results: A subset of autoreactive IRBP-specific CD8 T cells expressed IL-17. IRBP-specific T cells preferentially expressed IL-17 when expanded by IL-23, whereas IFN-gamma-expressing cells were dominant when the T cells were cultured with IL-2. Importantly, both expanded T-cell populations were uveitogenic. In addition, IL-23 promoted the expansion of antigen-specific and non-antigen-specific IL-17(+) T cells, whereas TGF-beta and IL-6 acted only on non-antigen-specific IL-17(+) T cells. Only the antigen-specific IL-17(+) T cells were uveitogenic. The activation of autoreactive IL-17(+) T cells was markedly increased in vivo by the mycobacterial component of CFA and pertussis toxin (PTX) and in vitro by the ligation of Toll-like receptors., Conclusions: IL-17(+) T cells can be readily detected among activated autoreactive and bystander T cells and may play a major role in the pathogenesis of EAU.

Foxp3-transduced CD4(+)T-cells have been used for treating autoimmune diseases such as type I diabetes. However, while suppressing the activity of pathogenic T cells, they could suppress the activity of bystander T cells as well. Therefore more specific strategies need to be developed. We designed and tested a new strategy that involves converting pathogenic CD4(+)Th1 cells into regulatory T-cells by lentiviral transduction with Foxp3 under the control of interferon-gamma (IFN-gamma) promoter (IgammaP-Foxp3). After transduction under the IgammaP control, Foxp3 expression in diabetic CD4(+)Th1 cells was favored. IgammaP-Foxp3-transduced CD4(+)T cells were anergic in vitro to stimulation by antigen. The process of IgammaP-Foxp3-transduced CD4(+)T cells differentiating into Treg cells and Treg cells losing their phenotype and functions has the effect of significantly suppressing incidence and onset of diabetes and autoantigen-specific T cell response, while increasing/maintaining endogenous Tregs in nonobese diabetic (NOD) mice recipients. In this manner, CD4(+)T cells of greater specificity were developed by transducing pathogenic CD4(+)Th1 cells with Foxp3 under the control of IgammaP, in order to prevent diabetes in NOD mice. The findings of this study provide a basis for more reasonable regulatory T cells (Tregs)-based therapy, with autoimmunity being suppressed through indirect means known as "infectious tolerance".