Naive CD45RA Research Articles

EFFECT OF REPETITIVE RFA ON THE IMMUNEVRESPONSE OF THE PATIENTS WITH INOPERABLE PANCREATIC CANCER

Annually, approximately 500,000 new cases of pancreatic ductal adenocarcinoma (PDAC) are diagnosed worldwide, with the same number of patients dying from this debilitating disease. Treatment resistance in PDAC results from the general immune suppression aggravated by the dense tumor stroma, which acts as a physical barrier to far too many treatment agents. Numerous studies suggest that RFA can trigger tumor-specific immune stimulation along with the disruption of the dense tumor stroma. Despite the immune stimulatory effect of RFA seen after procedure, a long-lasting clinical outcome of this procedure is hard to achieve. We aimed to explore the dynamics of immunological parameters in patients with PDAC treated with repetitive (three rounds of) RFA. Peripheral blood samples were analyzed from patients with inoperable pancreatic cancer who received three RFA treatments in a row, and compared to age-matched healthy controls.  Only repetitive, and not a sole, administration   of RFA actuated the decrease in protumorigenic cytokines (TGF-β, IL-17) and protumorigenic CD4+CD39+ and naive CD45RA T cells. Our study provides the first evidence on immunomodulatory benefits of repetitive RFA in patients with inoperable pancreatic cancer. Despite the fact that there was no other treatment used in the RFA group we still cannot attribute these immunologic changes to RFA alone. Larger scale studies involving different treatment modalities and complex immune readouts would guarantee more certainty to the clinical advantages of repetitive RFA.&nbsp

Aberrant T-cell exhaustion in severe combined immunodeficiency survivors with poor T-cell reconstitution after transplantation

Severe combined immunodeficiency (SCID) comprises rare inherited disorders of immunity that require definitive treatment through hematopoietic cell transplantation (HCT) or gene therapy for survival. Despite successes of allogeneic HCT, many SCID patients experience incomplete immune reconstitution, persistent T-cell lymphopenia, and poor long-term outcomes. We hypothesized that CD4+ T-cell lymphopenia could be associated with a state of T-cell exhaustion in previously transplanted SCID patients. We analyzed markers of exhaustion in blood samples from 61 SCID patients at a median of 10.4 years after HCT. Compared to post-HCT SCID patients with normal CD4+ T-cell counts, those with poor T-cell reconstitution showed lower frequency of naive CD45RA+/CCR7+ T cells, recent thymic emigrants, and TCR excision circles. They also had a restricted TCR repertoire, increased expression of inhibitory receptors (PD-1, 2B4, CD160, BTLA, CTLA-4), and increased activation markers (HLA-DR, perforin) on their total and naive CD8+ T cells, suggesting T-cell exhaustion and aberrant activation, respectively. The exhaustion score of CD8+ T cells was inversely correlated with CD4+ T-cell count, recent thymic emigrants, TCR excision circles, and TCR diversity. Exhaustion scores were higher among recipients of unconditioned HCT, especially when further in time from HCT. Patients with fewer CD4+ T cells showed a transcriptional signature of exhaustion. Recipients of unconditioned HCT for SCID may develop late post-HCT T-cell exhaustion as a result of diminished production of T-lineage cells. Elevated expression of inhibitory receptors on their T cells may be a biomarker of poor long-term T-cell reconstitution.

Evaluation of the prophylactic potential of non-enterotoxigenic Escherichia coli (non-ETEC) vaccine immunization and dietary mannan oligosaccharide competitive exclusion benefits against ETEC infections in weaned pigs

Enterotoxigenic Escherichia coli (ETEC) strains expressing F4 and F18 fimbriae are the most common causative agents of post-weaning diarrhoea (PWD) in pigs. The growing global restriction on the use of antibiotics in food animals has encouraged research into the development of nutritional and feeding strategies as well as vaccination against PWD. The aim of this study was to evaluate the efficacy of a live oral F4ac+ F18ac+ non-ETEC vaccine candidate (VAC) to stimulate gut and systemic cellular immunity in 4-week old pigs over 5 weeks following immunization. The onset and duration of protective immunity against on-farm occurring PWD, growth performance, diarrhoea scoring and mortality, as well as the phenotypic proportions of immune cells, were determined. Faecal and ileal samples were taken for determining the microbial composition or phenotyping of naïve/memory T cells. Also, the effect of prebiotic supplement mannan oligosaccharide (MOS) in the prevention of small intestinal colonization by ETEC, and its potential adjuvanticity in combination with the vaccine (VAC+MOS) were assessed. The pigs supplemented with MOS or that received VAC had significantly higher body weight (BW) (P<0.05) on Day 14, whereas the VAC+MOS treated pigs had significantly lower BW on Day 35. Treatment with VAC+MOS resulted in considerably reduced clinical PWD, in particular the incidence and severity of diarrhoea and mortality. The total bacterial load in the ileum was much lower in the pigs from all 3 principal groups (MOS, VAC, and VAC+MOS) than in the control (CON) group (19 x 107, 17 x 107 and 12 x 107 vs. 23 x 108 CFU/mL, respectively) on Day 35. The pigs from the principal groups had significantly higher proportions of tested immune cells (P<0.05) on Days 28 and 35. The localization and frequency of naive CD45RA+ and memory CD45RC+ T lymphocytes indicated their different distribution patterns within particular tissue structures, such as the villi, crypts, epithelium, lamina propria and areas (interfollicular follicular and Peyer’s patches) of ileal mucosa. This may indicate their different functions in intestinal immune responses to intraluminal microbes and their products, vaccinal immunogens and/or immunomodulators/adjuvants. To conclude, active mucosal immunity is needed to protect pigs against PWD. Hence, oral vaccination of pigs against both F4 and F18 ETEC, in combination with prebiotic supplementation represents a sustainable, practical and effective approach in PWD control.

Regulatory T-cell phenotypes in children with sickle cell disease.

Regulatory T cells (Tregs) are linked to a reduction in alloreactive immune responses, but few studies have investigated the impact of hydroxyurea (HU) therapy on Tregs in sickle cell disease (SCD). Our case-controlled study presented here included two groups, the first comprising 60 pediatric SCD patients, 30 of whom did not receive any treatment and 30 who received HU, and the second group consisting of 30 healthy controls. Flow cytometry was used to evaluate the percentage of CD4+CD25+highFoxp3+ Tregs present and their phenotypes. The percentage of CD4+CD25+high Tregs was significantly increased in untreated SCD patients in comparison to treated SCD patients and controls. Conversely, treated SCD children had a lower percentage of CD4+CD25+high Tregs than controls. In addition, a significant increase in the percentage of CD4+CD25+highFoxp3+ Tregs was found in untreated SCD patients, compared to in HU-treated patients and controls. The percentage of naive CD45RA+ Tregs was significantly decreased in untreated SCD patients when compared to other groups. Among children with SCD, HU treatment exhibited significant qualitative and quantitative effects on Tregs by decreasing their frequency, and increasing the proportion of naive CD45RA+ Tregs and reducing levels of the most suppressive Tregs: HLA-DR+, CD39+, and CD69+. Among children with, SCD, HU treatment exhibited significant qualitative and quantitative effects on Tregs. HU treatment in SCD decreases the frequency of Tregs, as well as the levels of the most suppressive Tregs: HLA-DR+, CD39+, and CD69+. At the same time, HU increases the proportion of naive CD45RA+ Tregs. Our study showed the impact of HU therapy on Tregs in children with SCD.

The Morphofunctional Response of T-lymphocytes to in vitro Contact with a Calcium Phosphate Coating in the Presence of a T-cell Activator

The paper reports a study of the morphofunctional activity of T-lymphocytes in response to the in vitro contact with calcium phosphate (CP) coating in the presence of the particles bearing antibodies against CD2, CD3, and CD28 antigens. VT1-0 titanium plates (10 × 10 × 1 mm3) with a double-sided microarc rough (Ra = 2–5 µm) CP coating were used as the model samples of the mineral matrix of the bone tissue. Magnetic particles (MACSiBeadTM T-cell Activation/Expansion Kit human) bearing antibodies to CD2, CD3, and CD28 antigens were used as a T-cell activator (TCA) simulating the signals produced by antigen-presenting cells (APCs). Mononuclear cells (MNCs) isolated from human blood (98.8% of CD45CD3+ cells) were cultured in the presence of samples with a CP coating and/or TCA (2 × 106 particles in 1.5 mL of nutritive medium in the proportion of 2 : 1 to cells) for 2 and 14 days. The CP coating and TCA triggered MNC culture adaptation in a synergic way via the mechanisms of hyperactivation and subsequent death of T-lymphocytes. Immune selection occurred through the accumulation of the naive CD45RA+/RO+ T-lymphocytes and memory T-cells with the simultaneous depletion of the CD4+ and CD8+ T-cell pool. The shift in the T-lymphocyte populations was observed together with the increase (after 48 h of culturing) in the cell secretion activity with its subsequent decrease by the 14th day of observation. CP coating sustained (compared with the cell culture grown on plastic) the secretion ability of Th1 (IL-12, TNFα, and IFNγ) and Th2 (IL-4, IL-6, IL-10, and IL-13) lymphocytes. At the same time, the prolonged TCA signal after the 48-h activation caused the depletion of T-cell secretion. The suggestion that the observed in vitro effects may play role in the switching of signaling between T-lymphocytes, APCs, and CP materials at the cell–foreign body interface, which may result in a change in the inflammation phase, development of immune tolerance, successful osseointegration of the implant, or bone tissue remodeling impairment, is discussed.

Haploidentical transplantation in pediatric non-malignant diseases: A retrospective analysis on behalf of the Spanish Group for Hematopoietic Transplantation (GETH).

Describe the GETH haploidentical stem cell transplantation (haplo-HSCT) activity in non-malignant disease (NMDs). We retrospectively analyzed data from children with NMDs who underwent haplo-HSCT. From January 2001 to December 2016, 26 pediatric patients underwent 31 haplo-HSCT through ex vivo T cell-depleted (TCD) graft platforms or post-transplantation cyclophosphamide (PT-Cy) at 7 Spanish centers. Five cases employed unmanipulated PT-Cy haplo-HSCT, 16 employed highly purified CD34+ cells, and 10 employed ex vivo TCD grafts manipulated either with CD3+ CD19+ depletion, TCRαβ+ CD19+ selection or naive CD45RA+ T-cell depletion. Peripheral blood stem cells were the sole source for patients following TCD haplo-HSCT, and bone marrow was the source for one PT-Cy haplo-HSCT. The most common indications for transplantation were primary immunodeficiency disorders (PIDs), severe aplastic anemia, osteopetrosis, and thalassemia. The 1-year cumulative incidence of graft failure was 27.4%. The 1-year III-IV acute graft-versus-host disease (GvHD) and 1-year chronic GvHD rates were 34.6% and 16.7%, respectively. The 2-year overall survival was 44.9% for PIDs, and the 2-year graft-versus-host disease-free and relapse-free survival rate was 37.6% for the other NMDs. The transplantation-related mortality at day 100 was 30.8%. Although these results are discouraging, improvements will come if procedures are centralized in centers of expertise.

Effects of pregnancy-specific β-1-glycoprotein on the helper T-cell response

Pregnancy-specific ?-1-glycoproteins (PSGs) are capable of regulating innate and adaptive immunity. As fetal antigens circulate in the blood of pregnant women, it is of particular interest to reveal the effects of PSGs on the differentiation of memory T cells in the context of maternal-fetal tolerance formation. We studied if, native PSG preparation affects helper T-cell proliferation, the frequencies of CD4+CD45R0+, CD4+CD45RA+, CD4+CD45RA+CD45R0+cells, naive CD45RA+CD45R0-CD62L+ cells (NAIVE), central memory CD45RA-CD45R0+CD62L+ cells (TCM), effector memory helper T cells (CD45RA-CD45R0+CD62L- (TEM) and CD45RA+CD45R0-CD62L- cells (TEMRA), together with IL-4 and IFN-? production by all ?D4+ T cells. The suppressive effect of PSG on helper T-cell proliferation was established. It was found that PSG does not influence the frequencies of CD45RA+ and CD45R0+ cells, while it decreased the percentage of CD45RA+CD45R0+ cells. PSG increased the percentage of NAIVE cells in culture, and prevented the conversion of these cells into TEMRA, without affecting the levels of TCM and TEM. In addition, PSG lowered the amount of IL-4 and IFN-? in the supernatants of helper T-cell cultures. As TEMRA exhibit cytotoxic activity that is unfavorable during pregnancy, the revealed PSG effects may play a fetoprotective role in vivo.

Прямое влияние гранулоцитарно-макрофагального колониестимулирующего фактора (GM-CSF) фактора на функциональные свойства Т-лимфоцитов человека

Актуальность. Исследовали прямые эффекты гранулоцит-макрофагального колониестимулирующего фактора (GM-CSF) человека на функциональную активность субпопуляций T-лимфоцитов. Методы. CD3+ Т-лимфоциты были выделены из крови здоровых доноров методом позитивной магнитной сепарации. T-клетки активировали частицами, конъюгированными с антителами (АТ) к молекулам CD3, СD28 и СD2 человека. Мембранную экспрессию CD3, CD4, СD45RA, СD197, CD25 и CD38 оценивали методом проточной цитофлюорометрии. Содержание интерферона- Результаты. Установлено, что GM-CSF в диапазоне концентраций 0,01-10,0 нг/мл не оказывал существенного влияния на содержание CD25+ клеток, среди активированных Т-лимфоцитов. Вместе с тем, GM-CSF в концентрации 0,1 и 1,0 нг/мл обладал способностью заметно увеличивать содержание CD38+ клеток среди наивных СD45RA+/СD197+ Т-клеток, а также среди СD45RA-/СD197+ Т-клеток центральной памяти, не оказывая при этом существенного влияния на экспрессию CD38, выявляемую среди эффекторных СD45RA-/СD197- и терминально дифференцированных СD45RA+/СD197- эффекторных Т-клеток. В относительно низкой концентрации (0,01 нг/мл) GM-CSF заметно снижал Т-клеточную продукцию INF-γ, тогда как в высокой концентрации (10,0 нг/мл) усиливал продукцию IL-2 и IL-4, снижая при этом выработку IL-10. Заключение. Полученные данные предполагают, что GM-CSF способен поддерживать активацию относительно низкодифференцированных Т-клеток, не оказывая при этом значимого влияния на активацию высоко дифференцированных Т-клеток. Background. We investigated direct effects of granulocyte-macrophage colony-stimulating factor (GM-CSF) on the functionality of T-lymphocyte subsets. Methods. CD3 + T cells were isolated from the blood of healthy donors by positive magnetic separation. The isolated T cells were activated with particles conjugated with antibodies (Abs) to human CD3, CD28, and CD2 molecules. The membrane expression of CD3, CD4, СD45RA, СD197, CD25, and CD38 was evaluated by flow cytofluorometry. Contents of interferon-γ (IFN- γ), interleukin-2 (IL-2), IL-4, and IL-10 in culture supernatants were determined by the enzyme immunoassay. Results. GM-CSF at 0.01-10.0 ng/ml had no significant effect on the content of CD25+ cells among activated T lymphocytes. At the same time, GM-CSF at 0.1-1.0 ng/ml was able to noticeably increase the content of CD38+ cells among both naive CD45RA+/CD197+ T cells and central memory CD45RA-/CD197+ T cells without affecting the СD38 expression on effector CD45RA- /CD197- and terminally differentiated CD45RA +/ CD197- effector T cells. At a relatively low concentration (0.01 ng/ml), GM-CSF significantly decreased T-cell production of INF-γ whereas at a high concentration (10.0 ng/ml), GM-CSF detectably enhanced the secretion of IL-2 and IL-4 while lowering IL-10 production. Conclusion. The findings suggest that GM-CSF is capable of supporting the activation of relatively low-differentiated T cells without significantly affecting the activation of highly differentiated T cells.

Differences in Cellular Composition of Peripheral Blood Stem Cell Grafts from Healthy Stem Cell Donors Mobilized with Either Granulocyte Colony-Stimulating Factor (G-CSF) Alone or G-CSF and Plerixafor

This study was conducted to characterize and compare peripheral blood stem cell grafts from healthy donors who underwent granulocyte colony-stimulating factor (G-CSF) mobilization and subsequently received 1 dose of plerixafor after insufficient stem cell yields were achieved at the first apheresis. Aliquots from 35 donors were collected from the first apheresis after mobilization with G-CSF alone and from the second apheresis after additional plerixafor administration. Samples were freshly analyzed for cellular subsets by 8-color flow cytometry. Leukapheresis samples mobilized with additional plerixafor showed a significant increase of total nucleated cells, including B cells, CD4+ and CD8+ T cells, and CD34+ hematopoietic stem and progenitor cells. Absolute numbers of plasmacytoid dendritic cells were also significantly increased, whereas no changes were detected for myeloid dendritic cells. Furthermore, absolute numbers of regulatory T cells increased, with naive CD45RA+ regulatory T cells showing the highest rise. Finally, strikingly higher numbers of myeloid-derived suppressor cells were detected in the plerixafor and G-CSF–mobilized graft. The mobilization of peripheral stem cells in healthy donors with G-CSF and plerixafor led to a significant difference in cellular graft composition compared with G-CSF alone. The clinical impact of the different cell composition for the graft recipient warrants further clinical investigation.

Antigen receptor-redirected T cells derived from hematopoietic precursor cells lack expression of the endogenous TCR/CD3 receptor and exhibit specific antitumor capacities

ABSTRACTRecent clinical studies indicate that adoptive T-cell therapy and especially chimeric antigen receptor (CAR) T-cell therapy is a very potent and potentially curative treatment for B-lineage hematologic malignancies. Currently, autologous peripheral blood T cells are used for adoptive T-cell therapy. Adoptive T cells derived from healthy allogeneic donors may have several advantages; however, the expected occurrence of graft versus host disease (GvHD) as a consequence of the diverse allogeneic T-cell receptor (TCR) repertoire expressed by these cells compromises this approach. Here, we generated T cells from cord blood hematopoietic progenitor cells (HPCs) that were transduced to express an antigen receptor (AR): either a CAR or a TCR with or without built-in CD28 co-stimulatory domains. These AR-transgenic HPCs were culture-expanded on an OP9-DL1 feeder layer and subsequently differentiated to CD5+CD7+ T-lineage precursors, to CD4+ CD8+ double positive cells and finally to mature AR+ T cells. The AR+ T cells were largely naive CD45RA+CD62L+ T cells. These T cells had mostly germline TCRα and TCRβ loci and therefore lacked surface-expressed CD3/TCRαβ complexes. The CD3− AR-transgenic cells were mono-specific, functional T cells as they displayed specific cytotoxic activity. Cytokine production, including IL-2, was prominent in those cells bearing ARs with built-in CD28 domains. Data sustain the concept that cord blood HPC derived, in vitro generated allogeneic CD3− AR+ T cells can be used to more effectively eliminate malignant cells, while at the same time limiting the occurrence of GvHD.

Failure of itraconazole to prevent T-helper type 2 cell immune deviation: Implications for chronic rhinosinusitis.

T-helper (Th) type 2 cell inflammation is the hallmark of several disease processes, including asthma, atopic dermatitis, and some forms of chronic rhinosinusitis. Itraconazole has been used as both an antifungal and an anti-inflammatory agent, with some success in many of these diseases, in part, by altering Th2 cytokine expression by T cells. It is not known whether this merely reflects inhibition of established Th2-like cells or the inhibition of differentiation of naive T cells into Th2-like cells. To evaluate the role of itraconazole in the differentiation of naive T cells during activation. Naive CD45RA+ T cells were isolated from peripheral blood mononuclear cells from healthy volunteers. Th1 and Th2 type cells were differentiated in the presence of varying concentrations of itraconazole. After stimulation with anti-CD3 and anti-CD28 beads, carboxyfluorescein succinimidyl ester dilution was performed to evaluate proliferation and intracellular cytokine staining for interleukin (IL) 4 and interferon (IFN) gamma within proliferating T cells was measured along with enzyme-linked immunosorbent assay for secreted IL-5, IL-13, and IFN gamma. Itraconazole had no effect on proliferation of unbiased, Th1, or Th2 cells. Similarly, there was no effect of itraconazole on either intracellular cytokine staining of IL-4 and IFN gamma or secreted cytokine expression of IFN gamma, IL-5, and IL-13 in any of the cell populations. Itraconazole did not alter the ability of naive T cells to proliferate or secrete cytokines under Th1 or Th2 deviating conditions in vitro. As such, reported inhibition of Th2-like lymphocyte function by itraconazole reflected action on mature effector cells and may have underscored why antifungal treatment failed in many clinical trials of eosinophilic chronic rhinosinusitis.

Relationship between levels of brain natriuretic peptide in blood and immune response in subjects

Elevated concentrations of Nt-pro-BNP were revealed in 11% of apparently healthy subjects aged 19–24 years and 22% of middle-aged (34–55 years) subjects. An increase in Nt-pro-BNP blood concentration was detected in 90% of patients with metabolic syndrome. Elevated levels of Nt-pro-BNP in peripheral blood occur with age. Higher concentrations of the peptide were revealed in women. Inhibition of lymphocytes proliferation and differentiation accompanied by increasing concentration of Nt-pro-BNP in blood is associated with a deficiency of the IL-2 level due to increased IL-10 concentration. Immunosuppressive effect of IL-10 declares itself at the level of innate immune reactions as a decrease in blood counts of naive CD45RA+ T lymphocytes, natural killer cells, T cells with adhesion receptor (CD56+) and adhesion receptor ligand (CD62L+). To prevent a loss of the intercellular pool, the effect of Nt-pro-BNP is activated. No statistically significant correlations between the increased Nt-pro-BNP concentration in blood and the content of serum IgM, IgG, IgA, IgE, IL-6, TNF-α, IFN-γ, CEC C1q, or С3d, as well as glucose, hemoglobin, transferrin, iron, or free fatty acids were revealed in apparently healthy subjects.

CD4+Foxp3-IL-10+ Tr1 Cells Promote Relapse of Diffuse Large B Cell Lymphoma by Enhancing the Survival of Malignant B Cells and Suppressing Antitumor T Cell Immunity.

Diffuse large B cell lymphoma (DLBCL) is a common B cell malignancy. Complete remission can be achieved in most patients by conventional treatment with rituximab and chemotherapy. However, a subset of remission individuals will develop a relapsed disease for obscure reasons. CD4+Foxp3-IL-10+ cell (Tr1) is a novel cell subtype with the capacity to suppress pro-inflammatory responses, but has not been extensively studied in most tumors. In this study, we investigated the potential role of Tr1 cells in DLBCL. We found that compared to that in healthy controls, the frequency of Tr1 cells was significantly increased in DLBCL patients, even during complete remission. Further study showed that these Tr1 cells were enriched in the CD25low/-Foxp3-CD49b+LAG-3+ fraction and could be developed in vitro from naive CD45RA+ CD4+ T cells. To examine the effect of Tr1 upregulation, we cocultured the enriched in vitro-induced Tr1 cells (iTr1) with autologous primary DLBCL cells and CD3+ T cells and found that iTr1 cells both enhanced the survival of CD20+ DLBCL tumor cells and suppressed the antitumor response of CD3+ T cells through the production of IL-10. Furthermore, the frequency of CD4+Foxp3-IL-10+ Tr1 cells in DLBCL patients during complete remission is directly associated with the risk of relapse. Together, these results suggested that Tr1 cells contributed to tumor cell maintenance and may serve as a prognostic marker and therapeutic target.

Cytokine-mediated regulation of expression of Gfi1 and U2afll4 genes activated by T-cells with different differentiation status in vitro

The dose-dependent effects of cytokines (IL-2, IL-7, and IL-15), which have a common g-chain, on mRNA expression of U2afll4 and GFi1 genes involved in regulation of alternative splicing of the Ptprc gene, have been investigated in vitro using T-lymphocyte cultures with different degrees of differentiation. IL-2, IL-7, and IL-15 caused a similar unidirectional inhibitory effect of various severity on restimulated CD45RO+ T-cells exposed to an antigen-independent activation; they caused a dose-dependent decrease of the U2af1l4 gene expression, and an increase of Gfi1 gene expression. This may suggest formation of active forms of the CD45 receptor, and also limitation of the formation of low-molecular short splice variants of the CD45RO receptor. Under conditions of antigen-independent stimulation of naive CD45RA+-cells rIL-7 and IL-15 exhibited opposite effects on U2af1l4 and Gfi1 gene expression. The increase of IL-7 concentrations in the incubation medium of naive cells was accompanied by a decrease in expression of both genes. IL-15 IL-7 exhibited opposite effects. Cytokines possessing a common g-chain (IL-2, IL-7, and IL-15) prevented antigen-independent differentiation of naive T-cells, by preventing the formation of polyclonal "surrogate" cells. In general, the study of the molecular mechanisms of genetic control determining homeostatic processes of T-cells in response to exposure to antigenic or non-antigenic treatments may be important for construction of a general model of self-maintenance and differentiation of immune cells.

Patient-individualized CD8⁺ cytolytic T-cell therapy effectively combats minimal residual leukemia in immunodeficient mice.

Adoptive transfer of donor-derived cytolytic T-lymphocytes (CTL) has evolved as a promising strategy to improve graft-versus-leukemia (GvL) effects in allogeneic hematopoietic stem-cell transplantation. However, durable clinical responses are often hampered by limited capability of transferred T cells to establish effective and sustained antitumor immunity in vivo. We therefore analyzed GvL responses of acute myeloid leukemia (AML)-reactive CD8(+) CTL with central and effector memory phenotype in a new allogeneic donor-patient specific humanized mouse model. CTL lines and clones obtained upon stimulation of naive CD45RA(+) donor CD8(+) T cells with either single HLA antigen-mismatched or HLA-matched primary AML blasts, respectively, elicited strong leukemia reactivity during cytokine-optimized short to intermediate (i.e., 2-8 weeks) culture periods. Single doses of CTL were intravenously infused into NOD/scidIL2Rcg(null) mice when engraftment with patient AML reached bone marrow infiltration of 1-5%, clinically defining minimal residual disease status. This treatment resulted in complete regression of HLA-mismatched and strong reduction of HLA-matched AML infiltration, respectively. Most importantly, mice receiving AML-reactive CTL showed significantly prolonged survival. Transferred CTL were detectable in murine bone marrow and spleen and demonstrated sustained AML-reactivity ex vivo. Moreover, injections with human IL-15 clearly promoted CTL persistence. In summary, we show that naive donor-derived CD8(+) CTL effectively combat patient AML blasts in immunodeficient mice. The donor-patient specific humanized mouse model appears suitable to evaluate therapeutic efficacy of AML-reactive CTL before adoptive transfer into patients. It may further help to identify powerful leukemia rejection antigens and T-cell receptors for redirecting immunity to leukemias even in a patient-individualized manner.

The role of recent thymic emigrant-regulatory T-cell (RTE-Treg) differentiation during pregnancy.

During pregnancy, regulatory T cells (Tregs) have a key role in maternal immune tolerance to the semi-allogeneic fetus. Our previous results showed that the naive CD45RA(+)-Treg pool is functionally improved in pregnant women compared with non-pregnant women. Therefore, we examined the thymic output and differentiation of CD45RA(+)CD31(+) recent thymic emigrant (RTE)-Tregs during normal pregnancy and in the presence of preeclampsia. With the onset of pregnancy, the composition of the total CD4(+)CD127(low+/-)FoxP3(+)-Treg pool changed in the way that its percentage of RTE- and CD45RA(-)CD31(+)-memory Tregs decreased strongly, whereas that of the CD45RA(+)CD31(-)-mature naive (MN)-Tregs did not change and that of the CD45RA(-)CD31(-)-memory Tregs increased complementary. Thereby, the ratio of RTE-/MN-Tregs decreased from 1.0 to 0.7 leading to a significant increase in the suppressive activity of the naive CD45RA(+)-Treg pool. This effect was confirmed by re-assembling separated RTE- and MN-Tregs from non-pregnant women in the ratio of pregnant women. The suppressive activity of both separated naive Treg subsets was equally high in non-pregnant and pregnant women, but considerably reduced in preeclampsia patients, who showed significantly increased percentages of CD45RA(-)CD31(+)-memory Tregs, but decreased percentages of RTE- and MN-Tregs. Our results suggest a reduced thymic output of RTE-Tregs during pregnancy, which causes a decrease in the ratio of RTE-/MN-Tregs and thus an increase in the differentiation of RTE-Tregs towards CD45RA(-)CD31(-)-memory Tregs. Presumably, this differentiation of RTE-Tregs, which was impaired in preeclampsia patients, ensures the improved suppressive activity of the CD45RA(+)-naive Treg pool and thus retains the maintenance of pregnancy.

Cytokine-mediated regulation of expression of Gfi1 and U2afll4 genes by activated T-cells with various differentiation status in vitro

The dose-dependent effects of cytokines (IL-2, IL-7, and IL-15), which have a common γ-chain, on mRNA expression of U2afll4 and GFi1 genes involved in regulation of alternative splicing of the Ptprc gene, have been investigated in vivo using T-lymphocyte cultures with different degrees of differentiation. IL-2, IL-7, and IL-15 caused a similar unidirectional inhibitory effect of various severity on restimulated CD45RO+ T-cells exposed to an antigen-independent activation; they caused a dose-dependent decrease of the U2af1l4 gene expression, and an increase of Gfi1 gene expression. This may suggest formation of active forms of the CD45 receptor, and also limitation of the formation of low-molecular short splice variants of the CD45RO receptor. Under conditions of antigen-independent stimulation of naive CD45RA+ - cells rIL-7 and IL-15 exhibited opposite effects on U2af1l4 and Gfi1 gene expression. The increase of IL-7 concentrations in the incubation medium of naive cells was accompanied by a decrease in expression of both genes. IL-15 IL-7 exhibited opposite effects. Cytokines possessing a common Γ-chain (IL-2, IL-7, and IL-15) prevented antigen-independent differentiation of naive T-cells, by preventing the formation of polyclonal “surrogate” cells. In general, the study of the molecular mechanisms of genetic control determining homeostatic processes of T-cells in response to exposure to antigenic or non-antigenic treatments may be important in the construction of a general model of self-maintenance and differentiation of immune cells.

The role of regulatory T cell (Treg) subsets in gestational diabetes mellitus

Physiological changes during normal pregnancy are characterized by an inflammatory immune response and insulin resistance. Therefore, we hypothesize that gestational diabetes mellitus (GDM) may be caused by an inappropriate adaption of the maternal immune system to pregnancy. In this study we examined the role of regulatory T cell (Treg) differentiation for the development of GDM during pregnancy. We used six-colour flow cytometric analysis to demonstrate that the total CD4(+) CD127(low+/-) CD25(+) forkhead box protein 3 (FoxP3(+)) T(reg) pool consists of four different T(reg) subsets: naive CD45RA(+) T(regs), HLA-DR(-) CD45RA(-) memory T(regs) (DR(-) T(regs)) and the highly differentiated and activated HLA-DR(low+) CD45RA(-) and HLA-DR(high+) CD45RA(-) memory T(regs) (DR(low+) and DR(high+) T(regs)). Compared to healthy pregnancies, the percentage of CD4(+) CD127(low+/-) CD25(+) FoxP3(+) T(regs) within the total CD4(+) T helper cell pool was not different in patients affected by GDM. However, the suppressive activity of the total CD4(+) CD127(low+/-) CD25(+) T(reg) pool was significantly reduced in GDM patients. The composition of the total T(reg) pool changed in the way that its percentage of naive CD45RA(+) T(regs) was decreased significantly in both patients with dietary-adjusted GDM and patients with insulin-dependent GDM. In contrast, the percentage of DR(-) -memory T(regs) was increased significantly in patients with dietary-adjusted GDM, while the percentage of DR(low+) and DR(high+) memory T(regs) was increased significantly in patients with insulin-dependent GDM. Hence, our findings propose that alterations in homeostatic parameters related to the development and function of naive and memory T(regs) may cause the reduction of the suppressive capacity of the total T(reg) pool in GDM patients. However, as this is an exploratory analysis, the results are only suggestive and require further validation.

Staphylococcus aureusconvert neonatal conventionalCD4+Tcells intoFOXP3+ CD25+ CD127lowTcells via thePD‐1/PD‐L1 axis

The gut microbiota provides an important stimulus for the induction of regulatory T (Treg) cells in mice, whether this applies to newborn children is unknown. In Swedish children, Staphylococcus aureus has become a common early colonizer of the gut. Here, we sought to study the effects of bacterial stimulation on neonatal CD4+ T cells for the induction of CD25+ CD127low Treg cells in vitro. The proportion of circulating CD25+ CD127low Treg cells and their expression of FOXP3, Helios and CTLA-4 was examined in newborns and adults. To evaluate if commensal gut bacteria could induce Treg cells, CellTrace violet-stained non-Treg cells from cord or peripheral blood from adults were co-cultured with autologous CD25+ CD127low Treg cells and remaining mononuclear cells and stimulated with S. aureus. Newborns had a significantly lower proportion of CD25+ CD127low Treg cells than adults, but these cells were Helios+ and CTLA-4+ to a higher extent than in adults. FOXP3+ CD25+ CD127low T cells were induced mainly in neonatal CellTrace-stained non-Treg cells after stimulation with S. aureus. In cell cultures from adults, S. aureus induced CD25+ CD127low T cells only if sorted naive CD45RA+ non-Treg cells were used, but these cells expressed less FOXP3 than those induced from newborns. Sorted neonatal CD25+ CD127low T cells from S. aureus-stimulated cultures were still suppressive. Finally, blocking PD-L1 during stimulation reduced the induction of FOXP3+ CD25+ CD127low T cells. These results suggest that newborns have a higher proportion of circulating thymically derived Helios+ Treg cells than adults and that S. aureus possess an ability to convert neonatal conventional CD4+ T cells into FOXP3+ CD25+ CD127low Treg cells via the PD-1/PD-L1 axis.

CD49d- Treg Cells with High Suppressive Capacity are Remarkably Less Efficient on Activated CD45RA- than on Naive CD45RA+ Teff Cells

Background: Impairment of regulatory T cells (Tregs) in common autoimmune diseases seems likely. However, the extent of Treg deficiency (number, function) or differential susceptibility of T effector cells (Teffs) to suppression is not completely understood. We hypothesize that even in healthy individuals both cell populations are heterogeneous and differ in their suppressive capability and their susceptibility to suppression. Material and Methods: Lymphocytes were enriched by MACS for CD4⁺CD25⁺ Tregs or CD4⁺CD25^- Teffs. After multicolour staining (anti-CD25, anti-CD127, anti-CD49d or anti-CD45RA) highly purified Treg and Teff subpopulations were collected by FACS. Functional capacity of Tregs or suppressive susceptibility of Teffs was analyzed in an in vitro assay. Results: When CD4⁺CD25^highCD127^-/low CD49d^- Tregs were tested on naive CD4⁺CD127⁺CD25^-CD45RA⁺ Teffs (93.8 %) suppression was almost complete, while the suppressive capacity of CD4⁺CD25^highCD127^-/low CD49d⁺ Tregs was significantly less (71.8 %). Suppressive activity was low when CD4⁺CD25^highCD127^-/low CD49d⁺ Tregs were analyzed on CD4⁺CD127⁺CD25^-CD45RA^- Teffs (48.7%). Conclusion: Although CD49d⁺ Tregs are functional, the suppressive capacity is significantly lower compared to CD49d^- Tregs. CD45RA⁺ Teffs can be completely suppressed, while CD45RA^- Teffs display relative resistance. Phenotypic and functional heterogeneity of Tregs as well as Teffs has to be considered when analyzing deficiencies in immune regulation.