Effective modulation of CD4+CD25+high regulatory T and NK cells in malignant patients by combination of interferon-α and interleukin-2

Overinduced CD4⁺CD25^+high regulatory T cells (Treg) and downregulated NK cells contribute to tumor-relevant immune tolerance and interfere with tumor immunity. In this study, we aimed to design a novel strategy with cytokine combination to correct the dysregulated Treg and NK cells in malignant patients. Initially, a total of 58 healthy individuals and 561 malignant patients were analyzed for their cellular immunity by flow cytometry. The average percentages of CD4⁺CD25^+high/lymphocyte were 1.30?±?1.19?% ( $ \bar{x} $ ?±?SD) in normal adults and 3.274?±?4.835?% in malignant patients (p?<?0.001). The ratio of CD4⁺CD25^+high to CD4⁺ was 3.58?±?3.19?% in normal adults and 6.01?±?5.89?% to 13.50?±?23.60?% in different kinds of malignancies (p?<?0.001). Of normal adults, 15.52?% had >3?% Treg and 12.07?% had <10?% NK cells. In contrast, the Treg (>3?%) and NK (<10?%) percentages were 40.82 and 34.94?% in malignant patients, respectively. One hundred and ten patients received the immunomodulation therapy with IFN-?? and/or IL-2. The overinduced Treg in 86.3?% and the reduced NK cells in 71.17?% of the patients were successfully modulated. In comparison, other lymphocyte subpopulations in most patients were much less affected by this treatment. No other treatment-relevant complications except slight pyrexia, fatigue, headache, and myalgia were observed. In conclusion, dysregulated Treg and/or NK cells were common in malignant patients. Different from any regimens ever reported, this strategy was simple and effective without severe complications and will become a basic regimen for other cancer therapies.     

Absence of β2 integrins impairs regulatory T cells and exacerbates CD4+ T cell-dependent autoimmune carditis

The immunopathogenic mechanisms mediating inflammation in multiorgan autoimmune diseases may vary between the different target tissues. We used the K/BxN TCR transgenic mouse model to investigate the contribution of CD4(+) T cells and β(2) integrins in the pathogenesis of autoimmune arthritis and endocarditis. Depletion of CD4(+) T cells following the onset of arthritis specifically prevented the development of cardiac valve inflammation. Genetic absence of β(2) integrins had no effect on the severity of arthritis and unexpectedly increased the extent of cardiovascular pathology. The exaggerated cardiac phenotype of the β(2) integrin-deficient K/BxN mice was accompanied by immune hyperactivation and was linked to a defect in regulatory T cells. These findings are consistent with a model in which the development of arthritis in K/BxN mice relies primarily on autoantibodies, whereas endocarditis depends on an additional contribution of effector T cells. Furthermore, strategies targeting β(2) integrins for the treatment of systemic autoimmune conditions need to consider not only the role of these molecules in leukocyte recruitment to sites of inflammation, but also their impact on the regulation of immunological tolerance.     

Effects of Sirolimus treatment on patients with β-Thalassemia: Lymphocyte immunophenotype and biological activity of memory CD4+ and CD8+ T cells

Inhibitors of the mammalian target of rapamycin (mTOR) have been proposed to improve vaccine responses, especially in the elderly. Accordingly, testing mTOR inhibitors (such as Sirolimus) and other geroprotective drugs might be considered a key strategy to improve overall health resilience of aged populations. In this respect, Sirolimus (also known as rapamycin) is of great interest, in consideration of the fact that it is extensively used in routine therapy and in clinical studies for the treatment of several diseases. Recently, Sirolimus has been considered in laboratory and clinical studies aimed to find novel protocols for the therapy of hemoglobinopathies (e.g. β-Thalassemia). The objective of the present study was to analyse the activity of CD4⁺ and CD8⁺ T cells in β-Thalassemia patients treated with Sirolimus, taking advantages from the availability of cellular samples of the NCT03877809 clinical trial. The approach was to verify IFN-γ releases following stimulation of peripheral blood mononuclear cells (PBMCs) to stimulatory CEF and CEFTA peptide pools, stimulatory for CD4⁺ and CD8⁺ T cells, respectively. The main results of the present study are that treatment of β-Thalassemia patients with Sirolimus has a positive impact on the biological activity and number of memory CD4⁺ and CD8⁺ T cells releasing IFN-γ following stimulation with antigenic stimuli present in immunological memory. These data are to our knowledge novel and in our opinion of interest, in consideration of the fact that β-Thalassemia patients are considered prone to immune deficiency.     

T cell receptor-mediated activation of CD4+CD44hi T cells bypasses Bcl10: an implication of differential NF-kappaB dependence of naïve and memory T cells during T cell receptor-mediated responses

Previous studies have demonstrated that Bcl10 (B-cell leukemia/lymphoma 10) is essential for T cell receptor-mediated NF-kappaB activation and subsequent proliferation and interleukin 2 (IL2) production. However, here we demonstrate that, contrary to expectations, Bcl10 is differentially required for T cell activation, including for both proliferation and cytokine production. When CD4+ and CD8+ T cells were divided based on expression levels of CD44, which distinguishes na?ve cells (CD44lo) versus those that are antigen-experienced (CD44hi), IL2 production by and proliferation of CD4+CD44lo na?ve cells and both subpopulations of CD8+ T cells were clearly Bcl10-dependent, whereas these same functional properties of CD4+CD44hi T cells occurred largely independent of Bcl10. As with the other subpopulations of T cells, CD4+CD44hi T cells did not activate the NF-kappaB pathway in the absence of Bcl10; nevertheless, these CD4+CD44hi antigen-experienced T cells efficiently secreted IL2 after T cell receptor stimulation. Strikingly, therefore, T cell receptor-mediated IL2 production in these cells is NF-kappaB-independent. Our studies suggest that antigen-experienced CD4+ T cells differ from their na?ve counterparts and from CD8+ T cells in their ability to achieve activation independent of the Bcl10/NF-kappaB pathway.     

Age-associated changes in interferon-γ and interleukin-4 secretion by purified human CD4+ and CD8+ T cells

Aging is associated with a decline in immune function. Interferon-gamma (IFN-gamma) and interleukin-4 (IL-4), two important immune deviation-related cytokines, are mainly produced by type 1 and type 2 T cells, respectively. To investigate the age-associated changes in the secretion of these two cytokines, 20 elderly and 20 young subjects fulfilling the SENIEUR protocol were enrolled. The ratios of CD4+ to CD8+ T cells were not different between the two age groups. The CD4+ and CD8+ T cells were purified by a magnetic cell sorting system, and then activated by concurrent anti-CD3 and anti-CD28 stimulation. The released cytokines were determined by ELISA. Both the CD4+ and the CD8+ T cells of the elderly individuals secreted a significantly larger amount of IFN-gamma after activation. Profound IL-4 production by CD8+ T cells was observed in the older subjects compared with that of the young subjects. These data suggested that age-associated decrease in immunity may be related to an imbalance in the secretion of immune deviation cytokines. The number of IL-4-secreting CD8+ T cells (T cytotoxic 2) rose significantly in the older individuals. Our design also provided a useful way to differentiate the T cell subsets secreting the same cytokine, such as IFN-gamma-producing T helper 1 and T cytotoxic 1 cells.     

Comparative kinetic analyses of gene profiles of naïve CD4+ and CD8+ T cells from young and old animals reveal novel age-related alterations

It is well established that immune responses are diminished in the old. However, we still do not have a clear understanding of what dictates the dysfunction of old T cells at the molecular level. Although microarray analysis has been used to compare young and old T cells, identifying hundreds of genes that are differentially expressed among these populations, it has been difficult to utilize this information to pinpoint which biological pathways truly affect the function of aged T cells. To better define differences between young and old naïve CD4⁺ and CD8⁺ T cells, microarray analysis was performed pre‐ and post‐TCR stimulation for 4, 12, 24 and 72 h. Our data indicate that many genes are differentially expressed in the old compared to the young at all five time points. These genes encode proteins involved in multiple cellular functions such as cell growth, cell cycle, cell death, inflammatory response, cell trafficking, etc. Additionally, the information from this microarray analysis allowed us to underline both intrinsic deficiencies and defects in signaling only seen after activation, such as pathways involving T‐cell signaling, cytokine production, and Th2 differentiation in old T cells. With the knowledge gained, we can proceed to design strategies to restore the function of old T cells. Therefore, this microarray analysis approach is a powerful and sensitive tool that reveals the extensive changes seen between young and old CD4⁺ and CD8⁺ naïve T cells. Evaluation of these differences provides in‐depth insight into potential functional and phenotypical differences among these populations.     

Human CD8+CD25 +CD127 low regulatory T cells: microRNA signature and impact on TGF-β and IL-10 expression

Regulatory T cells (Tregs) are central for maintaining immune balance and their dysfunction drives the expansion of critical immunologic disorders. During the past decade, microRNAs (miRNAs) have emerged as potent regulators of gene expression among which immune-related genes and their immunomodulatory properties have been associated with different immune-based diseases. The miRNA signature of human peripheral blood (PB) CD8⁺CD25 ⁺CD127 ^low Tregs has not been described yet. We thus identified, using TaqMan low-density array (TLDA) technique followed by individual quantitative real-time polymerase chain reaction (qRT-PCR) confirmation, 14 miRNAs, among which 12 were downregulated whereas two were upregulated in CD8 ⁺CD25 ⁺CD127 ^low Tregs in comparison to CD8 ⁺CD25 ⁻ T cells. In the next step, microRNA Data Integration Portal (mirDIP) was used to identify potential miRNA target sites in the 3′-untranslated region (3′-UTR) of key Treg cell-immunomodulatory genes with a special focus on interleukin 10 (IL-10) and transforming growth factor β (TGF-β). Having identified potential miR target sites in the 3′-UTR of IL-10 (miR-27b-3p and miR-340-5p) and TGF-β (miR-330-3p), we showed through transfection and transduction assays that the overexpression of two underexpressed miRNAs, miR-27b-3p and miR-340-5p, downregulated IL-10 expression upon targeting its 3′-UTR. Similarly, overexpression of miR-330-3p negatively regulated TGF-β expression. These results highlighted an important impact of the CD8 ⁺ Treg mirnome on the expression of genes with significant implication on immunosuppression. These observations could help in better understanding the mechanism(s) orchestrating Treg immunosuppressive function toward unraveling new targets for treating autoimmune pathologies and cancer.     

Involvement of CD56brightCD11c+ cells in IL-18-mediated expansion of human γδ T cells

γδ T cells are considered to be innate lymphocytes that play an important role in host defense against tumors and infections. We recently reported that IL-18 markedly amplified γδ T cell responses to zoledronate (ZOL)/IL-2. In an extension of this finding, we analyzed the mechanism underlying the IL-18-mediated expansion of γδ T cells. After incubation of PBMCs with ZOL/IL-2/IL-18, the majority of the cells expressed γδ TCR, and the rest mostly exhibited CD56(bright)CD11c(+) under the conditions used in this study. CD56(bright)CD11c(+) cells were derived from a culture of CD56(int)CD11c(+) cells and CD14(+) cells in the presence of IL-2 and IL-18 without the addition of ZOL. They expressed IL-18Rs, HLA-DR, CD25, CD80, CD83, CD86, and CD11a/CD18. In addition, they produced IFN-γ, TNF-α, but not IL-12, when treated with IL-2/IL-18, and they exerted cytotoxicity against K562 cells, thus exhibiting characteristics of both NK cells and dendritic cells. Incubation of purified γδ T cells with CD56(bright)CD11c(+) cells in the presence of ZOL/IL-2/IL-18 resulted in the formation of massive cell clusters and led to the marked expansion of γδ T cells. However, both conventional CD56(-/int)CD11c(high) dendritic cells induced by GM-CSF/IL-4 and CD56(+)CD11c(-) NK cells failed to support the expansion of γδ T cells. These results strongly suggest that CD56(bright)CD11c(+) cells play a key role in the IL-18-mediated proliferation of γδ T cells.     

Inflammasome-derived IL-1β regulates the production of GM-CSF by CD4(+) T cells and γδ T cells

Recent findings have demonstrated an indispensable role for GM-CSF in the pathogenesis of experimental autoimmune encephalomyelitis. However, the signaling pathways and cell populations that regulate GM-CSF production in vivo remain to be elucidated. Our work demonstrates that IL-1R is required for GM-CSF production after both TCR- and cytokine-induced stimulation of immune cells in vitro. Conventional αβ and γδ T cells were both identified to be potent producers of GM-CSF. Moreover, secretion of GM-CSF was dependent on IL-1R under both IL-12- and IL-23-induced stimulatory conditions. Deficiency in IL-1R conferred significant protection from experimental autoimmune encephalomyelitis, and this correlated with reduced production of GM-CSF and attenuated infiltration of inflammatory cells into the CNS. We also find that GM-CSF production in vivo is not restricted to a defined CD4(+) T cell lineage but is rather heterogeneously expressed in the effector CD4(+) T cell population. In addition, inflammasome-derived IL-1β upstream of IL-1R is a critical regulator of GM-CSF production by T cells during priming, and the adapter protein, MyD88, promotes GM-CSF production in both αβ and γδ T cells. These findings highlight the importance of inflammasome-derived IL-1β and the IL-1R/MyD88 signaling axis in the regulation of GM-CSF production.     

Are CD4+CD25-Foxp3+ cells in untreated new-onset lupus patients regulatory T cells?

Introduction  

Our previous study has reported that, in patients with untreated new-onset lupus (UNOL), there was an abnormal increase in the number of CD4⁺CD25^-Foxp3⁺ T cells that correlated with disease activity and significantly decreased after treatment. However, little is known about the nature of this cell entity. The aim of this study was to explore the nature of abnormally increased CD4⁺CD25^-Foxp3⁺ T cells in UNOL patients.     

Existence of MHC class I-restricted alloreactive CD4+ T cells reacting with peptide transporter-deficient cells

It is generally accepted that as the result of positive thymic selection, CD8-expressing T cells recognize peptide antigens presented in the context of MHC class I molecules and CD4-expressing T cells interact with peptide antigens presented by MHC class II molecules. Here we report the generation of TCRalpha/beta(+), CD3(+), CD4(+), CD8(-), MHC class I-restricted alloreactive T-cell clones which were induced using peripheral blood mononuclear cells from healthy individuals following in vitro stimulation with transporter associated with antigen processing (TAP)-deficient cell lines T2. The CD4(+) T-cell clones showed an HLA-A2.1-specific proliferative response against T2 cells which was inhibited by anti-CD3 and anti-CD4 monoclonal antibodies. These results suggest that interaction of the TCR with peptide-bound HLA class I molecules contributes to antigen-specific activation of these co-receptor-mismatched T-cell clones. Antigen recognition by alloreactive MHC class I-restricted CD4(+) T cells was inhibited by removing peptides bound to HLA molecules on T2 cells suggesting that the alloreactive CD4(+) T cells recognize peptides that bind in a TAP-independent manner to HLA-A2 molecules. The existence of such MHC class I-restricted CD4(+) T cells which can recognize HLA-A2 molecules in the absence of TAP function may provide a basis for the development of immunotherapy against TAP-deficient tumor variants which would be tolerant to immunosurveillance by conventional MHC class I-restricted cytotoxic lymphocytes.     

HSP70 Enhances Immunosuppressive Function of CD4+CD25+FoxP3+ T Regulatory Cells and Cytotoxicity in CD4+CD25? T Cells

Human CD4⁺CD25⁺FoxP3⁺ T regulatory cells (Tregs) control effector T cells and play a central role in peripheral tolerance and immune homeostasis. Heat shock protein 70 (HSP70) is a major immunomodulatory molecule, but its effect on the functions of Tregs is not well understood. To investigate target-dependent and –independent Treg functions, we studied cytokine expression, regulation of proliferation and cytotoxicity after exposure of Tregs to HSP70. HSP70-treated Tregs significantly inhibited proliferation of CD4⁺CD25⁻ target cells and downregulated the secretion of the proinflammatory cytokines IFN-γ and TNF-α. By contrast, HSP70 increased the secretion of Treg suppressor cytokines IL-10 and TGF-β. Treatment with HSP70 enhanced the cytotoxic properties of Tregs only to a minor extent (4-fold), but led to stronger responses in CD4⁺CD25⁻ cells (42-fold). HSP70-induced modulation of T-cell responses was further enhanced by combined treatment with HSP70 plus IL-2. Treatment of Tregs with HSP70 led to phosphorylation of PI3K/AKT and the MAPKs JNK and p38, but not that of ERK1/2. Exposure of Tregs to specific inhibitors of PI3K/AKT and the MAPKs JNK and p38 reduced the immunosuppressive function of HSP70-treated Tregs as indicated by the modified secretion of specific target cell (IFN-γ, TNF-α) and suppressor cytokines (IL-10, TGF-β). Taken together, the data show that HSP70 enhances the suppressive capacity of Tregs to neutralize target immune cells. Thus HSP70-enhanced suppression of Tregs may prevent exaggerated immune responses and may play a major role in maintaining immune homeostasis.     

Role of CD4+ and CD8α+ T cells in protective immunity against Edwardsiella tarda infection of ginbuna crucian carp,Carassius auratus langsdorfii

Edwardsiella tarda is an intracellular pathogen that causes edwardsiellosis in fish. Our previous study suggests that cell-mediated immunity (CMI) plays an essential role in protection against E. tarda infection. In the present study, we adoptively transferred T-cell subsets sensitized with E. tarda to isogenic naïve ginbuna crucian carp to determination the T-cell subsets involved in protecting fish from E. tarda infection. Recipients of CD4⁺ and CD8α⁺ cells acquired significant resistance to infection with E. tarda 8 days after sensitization, indicating that helper T cells and cytotoxic T lymphocytes plays crucial roles in protective immunity to E. tarda. Moreover, transfer of sensitized CD8α⁺ cells up-regulated the expression of genes encoding interferon-γ (IFN-γ) and perforin, suggesting that protective immunity to E. tarda involves cell-mediated cytotoxicity and interferon-γ-mediated induction of CMI. The results establish that CMI plays a crucial role in immunity against E. tarda. These findings provide novel insights into understanding the role of CMI to intracellular pathogens of fish.