Reduction in CD4 central memory T-cell subset in costimulation modulator abatacept-treated patients with recent-onset type 1 diabetes is associated with slower C-peptide decline.
ABSTRACT: We previously reported that continuous 24-month costimulation blockade by abatacept significantly slows the decline of ?-cell function after diagnosis of type 1 diabetes. In a mechanistic extension of that study, we evaluated peripheral blood immune cell subsets (CD4, CD8-naive, memory and activated subsets, myeloid and plasmacytoid dendritic cells, monocytes, B lymphocytes, CD4(+)CD25(high) regulatory T cells, and invariant NK T cells) by flow cytometry at baseline and 3, 6, 12, 24, and 30 months after treatment initiation to discover biomarkers of therapeutic effect. Using multivariable analysis and lagging of longitudinally measured variables, we made the novel observation in the placebo group that an increase in central memory (CM) CD4 T cells (CD4(+)CD45R0(+)CD62L(+)) during a preceding visit was significantly associated with C-peptide decline at the subsequent visit. These changes were significantly affected by abatacept treatment, which drove the peripheral contraction of CM CD4 T cells and the expansion of naive (CD45R0(-)CD62L(+)) CD4 T cells in association with a significantly slower rate of C-peptide decline. The findings show that the quantification of CM CD4 T cells can provide a surrogate immune marker for C-peptide decline after the diagnosis of type 1 diabetes and that costimulation blockade may exert its beneficial therapeutic effect via modulation of this subset.
Project description:Stimulation with antibodies to CD3 and CD28 coimmobilized on beads can be used to significantly expand T cells ex vivo. With CD4 T cells from HIV-infected patients, this expansion usually is accompanied by complete suppression of viral replication, presumed to be caused by down-regulation of the viral coreceptor CCR5 and up-regulation of CCR5 ligands. Here we show that this suppression occurs in total CD4 T cells acutely infected with R5 HIV, but not in purified CD62L(-) memory CD4 T cells. The lack of complete suppression in these memory cells, typically comprising 10-40% of total CD4 T cells, occurs despite high levels of CCR5 ligand secretion and down-regulation of CCR5. Significantly, adding back naive or CD62L(+) memory CD4 T cells inhibits the viral replication in the CD62L(-) cells, with the naive cells capable of completely repressing the virus. Although this inhibition was previously thought to be specific to bead-bound anti-CD3/CD28 stimulation, we show that the same suppression is obtained with sufficiently strong anti-CD3/B7.1 stimulation. Our results show that inhibitory mechanisms, expressed predominantly by strongly stimulated naive CD4 T cells and mediated independently of CCR5-binding chemokines, play a role in the inhibition of R5 HIV replication in CD4 T cells upon CD28 costimulation.
Project description:OBJECTIVE We previously reported that 2 years of costimulation modulation with abatacept slowed decline of β-cell function in recent-onset type 1 diabetes (T1D). Subsequently, abatacept was discontinued and subjects were followed to determine whether there was persistence of effect. RESEARCH DESIGN AND METHODS Of 112 subjects (ages 6-36 years) with T1D, 77 received abatacept and 35 received placebo infusions intravenously for 27 infusions over 2 years. The primary outcome-baseline-adjusted geometric mean 2-h area under the curve (AUC) serum C-peptide during a mixed-meal tolerance test (MMTT) at 2 years-showed higher C-peptide with abatacept versus placebo. Subjects were followed an additional year, off treatment, with MMTTs performed at 30 and 36 months. RESULTS C-peptide AUC means, adjusted for age and baseline C-peptide, at 36 months were 0.217 nmol/L (95% CI 0.168-0.268) and 0.141 nmol/L (95% CI 0.071-0.215) for abatacept and placebo groups, respectively (P = 0.046). The C-peptide decline from baseline remained parallel with an estimated 9.5 months' delay with abatacept. Moreover, HbA1c levels remained lower in the abatacept group than in the placebo group. The slightly lower (nonsignificant) mean total insulin dose among the abatacept group reported at 2 years was the same as the placebo group by 3 years. CONCLUSIONS Costimulation modulation with abatacept slowed decline of β-cell function and improved HbA1c in recent-onset T1D. The beneficial effect was sustained for at least 1 year after cessation of abatacept infusions or 3 years from T1D diagnosis.
Project description:Abatacept is a recombinant CTLA-4 moleculed fused to a mutated human IgG molecule, which is clinically used in rheumatoid arthritis by inhibiting CD28-costimulation. This study aimed to inverstigate the ability of abatacept -mediated costimulation blockade to induce antigen-specific tolerance during primary immune responses. This is important as some studies have suggested that costimulation blockade can lead to CD4+ T cell anergy which could be beneficial for early therapy of autoimmune diseases such as rheumatoid arthritis. In addition we also investigated the effect that abatacept has on CD11c+ antigen presenting cells. This is important as costimulation blocakde can affect the biderectional interaction between CD4+ T cells and CD11c+ cells influencing the immunological outcome. We used microarrays to identify if abatacept treatment leads to antigen specific anergy using transgenic animals and models of priming and oral tolerance that established a synchronised monoclonal response. In addition this magnified the effect on the CD11c+ antigen presenting cells. This study included 5 experimental groups. DO11.10 RAG2-/- mice have CD4+ T cells specific for the ovalbumin (OVA) peptide OVA323-339. These mice were immunised with CFA/OVA s.c. (primed group) or tolerised by feeding with OVA (50mg/kg) in the drinking water. CD4+ cells were isolated 10 days post immunisation from draining lymph nodes (LNs) of unimmunised (pooled LNs and Spleen), orally tolerised (mesenteric LNs), primed (axillary LNs), primed treated with control IgG (axillary LNs) and primed treated with abatacept (axillary LNs). For CD11c+ cells cells were isolated by pooled secondary lymphoid organs (LNs and spleen).
Project description:Objectives: Immune responses in migraine are poorly characterized, yet implicated in the disease pathogenesis. This study was carried out to characterize purinergic profiles of T-cells in patients with episodic migraine without aura (MWoA) to provide mechanistic evidence for ATP and adenosine involvement in modulation of immune regulation in migraine. Methods: Peripheral blood samples were obtained from patients with migraine (n = 16) and age-matched control subjects (n = 21). Subsets of T-cells were identified by flow cytometry based on specific membrane markers. Results: Migraine patients showed reduced total T-cell counts in the peripheral blood. Whereas the total number of CD3+CD4+, CD3+CD8+, or regulatory T lymphocytes (Treg) was not changed, the proportion of Treg CD45R0+CD62L- and CD45R0-CD62L- cells was increased. Interestingly, in migraine, less Treg cells expressed CD39 and CD73 suggesting disrupted ATP breakdown to adenosine. The negative correlations were observed between the duration of migraine and the relative number of CD73+CD39- Tregs and total number of CD73-positive CD45R0+CD62L+ Tregs. Conclusion: Obtained data indicate that T-cell populations are altered in episodic migraine and suggest the involvement of Tregs in the pathophysiology of this disorder. Reduced expression of CD39 and CD73 suggests promotion of ATP-dependent pro-inflammatory and reduction of adenosine-mediated anti-inflammatory mechanisms in migraine.
Project description:Despite improvement in the prognosis of HIV/AIDS (human immunodeficiency virus/acquired immune deficiency syndrome) patients on antiretroviral therapy (ART), cryptococcal meningitis (CM) still causes 10-15% mortality among HIV-infected patients. The immunological impact of ART on the CD4+ and CD8+ T cell repertoire during cryptococcal co-infection is unclear. We determined longitudinal phenotypic changes in T cell subsets among patients with CM after they initiated ART. We hypothesized that ART alters the clonotypic phenotype and structural composition of CD4+ and CD8+ T cells during CM co-infection. For this substudy, peripheral blood mononuclear cells (PBMC) were isolated at four time points from CM patients following ART initiation during the parent study (ClinicalTrials.gov number, NCT01075152). Phenotypic characterization of CD4+ and CD8+ T cells was done using T cell surface marker monoclonal antibodies by flow cytometry. There was variation in the expression of immunophenotypic markers defining central memory (CD27+CD45R0+), effector memory (CD45R0+CD27-), immune activation (CD38+ and Human Leucocyte Antigen DR (HLA-DR+), and exhaustion (Programmed cell death protein one (PD-1) in the CD4+ T cell subset. In comparison to the CD4+ T cell population, the CD8+ central memory subset declined gradually with minimal increase in the effector memory subset. Both CD4+ and CD8+ T cell immune exhaustion and activation markers remained elevated over 12 weeks. The relative surge and decline in the expression of T cell surface markers outlines a variation in the differentiation of CD4+ T cells during ART treatment during CM co-infection.
Project description:Neonatal CD4(+) T cells have traditionally been viewed as deficient in their capacity to produce Th1 cytokines in response to polyclonal or Ag-specific stimuli. Thus, defining unique aspects of CD4(+) T cell activation and development into Th1 effector cells in neonates is essential to the successful development of novel vaccines and immunotherapies to protect infants from intracellular pathogens. Using highly purified naive CD4(+) T cells derived from cord and adult peripheral blood, we compared the impact of anti-CD3 stimulation plus costimulation through TLR-2 performed in the absence of APC on CD4(+) T cell cytokine production, proliferation, and expression of activation markers. In both age groups, TLR-2 costimulation elicited activation of naive CD4(+) T cells, characterized by robust production of IL-2 as well as key Th1-type cytokines IFN-? and TNF-?. TLR-2 costimulation also dramatically reduced naive T cell production of the immunosuppressive cytokine IL-10. We observed that neonatal naive CD4(+) T cells are uniquely sensitive to TLR-2-mediated costimulation, which enabled them to produce equivalent amounts of IFN-? and more IL-2 when compared with adult responses. Thus, neonatal CD4(+) T cells have a distinctive propensity to use TLR-2-mediated costimulation for development into proinflammatory Th1 effectors, and interventions that target CD4(+) T cell TLR-2-mediated responses may be exploited to enhance neonatal adaptive immunity.
Project description:Peptide immunotherapy (PIT) offers realistic prospects for the treatment of allergic diseases, including allergic asthma. Much is understood of the behavior of naive T cells in response to PIT. However, treatment of patients with ongoing allergic disease requires detailed understanding of the responses of allergen-experienced T cells. CD62L expression by allergen-experienced T cells corresponds to effector/effector memory (CD62L(lo)) and central memory (CD62L(hi)) subsets, which vary with allergen exposure (e.g., during, or out with, pollen season). The efficacy of PIT on different T helper 2 (Th2) cell memory populations is unknown. We developed a murine model of PIT in allergic airway inflammation (AAI) driven by adoptively transferred, traceable ovalbumin-experienced Th2 cells. PIT effectively suppressed AAI driven by unfractionated Th2 cells. Selective transfer of CD62L(hi) and CD62L(lo) Th2 cells revealed that these two populations behaved differently from one another and from previously characterized (early deletional) responses of naive CD4(+) T cells to PIT. Most notably, allergen-reactive CD62L(lo) Th2 cells were long-lived within the lung after PIT, before allergen challenge, in contrast to CD62L(hi) Th2 cells. Despite this, PIT was most potent against CD62L(lo) Th2 cells in protecting from AAI, impairing their ability to produce Th2 cytokines, whereas this capacity was heightened in PIT-treated CD62L(hi) Th2 cells. We conclude that Th2 cells do not undergo an early deletional form of tolerance after PIT. Moreover, memory Th2 subsets respond differently to PIT. These findings have implications for the clinical translation of PIT in different allergic scenarios.
Project description:CD4(+) T-cell loss is the hallmark of HIV-1 infection. CD4 counts fall more rapidly in advanced disease when CCR5-tropic viral strains tend to be replaced by X4-tropic viruses. We hypothesized: (i) that the early dominance of CCR5-tropic viruses results from faster turnover rates of CCR5(+) cells, and (ii) that X4-tropic strains exert greater pathogenicity by preferentially increasing turnover rates within the CXCR4(+) compartment. To test these hypotheses we measured in vivo turnover rates of CD4(+) T-cell subpopulations sorted by chemokine receptor expression, using in vivo deuterium-glucose labeling. Deuterium enrichment was modeled to derive in vivo proliferation (p) and disappearance (d*) rates which were related to viral tropism data. 13 healthy controls and 13 treatment-naive HIV-1-infected subjects (CD4 143-569 cells/ul) participated. CCR5-expression defined a CD4(+) subpopulation of predominantly CD45R0(+) memory cells with accelerated in vivo proliferation (p = 2.50 vs 1.60%/d, CCR5(+) vs CCR5(-); healthy controls; P<0.01). Conversely, CXCR4 expression defined CD4(+) T-cells (predominantly CD45RA(+) naive cells) with low turnover rates. The dominant effect of HIV infection was accelerated turnover of CCR5(+)CD45R0(+)CD4(+) memory T-cells (p = 5.16 vs 2.50%/d, HIV vs controls; P<0.05), naïve cells being relatively unaffected. Similar patterns were observed whether the dominant circulating HIV-1 strain was R5-tropic (n = 9) or X4-tropic (n = 4). Although numbers were small, X4-tropic viruses did not appear to specifically drive turnover of CXCR4-expressing cells (p = 0.54 vs 0.72 vs 0.44%/d in control, R5-tropic, and X4-tropic groups respectively). Our data are most consistent with models in which CD4(+) T-cell loss is primarily driven by non-specific immune activation.
Project description:Acute infection leads to CD8(+) T-cell activation, division and differentiation. Following clearance of infection, cells revert to two distinct subsets of memory, central (T(CM)) and effector (T(EM)) memory. Adoptive transfer of naive T-cell receptor transgenic (TCR-tg) T cells has been used to study the differentiation of these memory subsets, which are often discriminated by expression of CD62L. Naive CD8(+) T cells are CD62L(high), and CD62L expression is lost during the 'effector' phase. Adoptive transfer studies show that higher transfer frequencies result in diminished T-cell expansion and a higher proportion CD62L(high). This suggests a relationship between CD62L expression and cell division, where division leads to conversion from CD62L(high) to CD62L(low) phenotype. To address this hypothesis we adoptively transferred graded numbers of OT-1 TCR-tg T cells from naive donors and tracked the kinetics and phenotype of the immune response after infection. We developed a simple mathematical model of division-linked CD62L differentiation, which we compared with the experimental data. Our results show that division-linked differentiation predicts the differences in proportion of cells CD62L(high) observed between responses of different adoptive transfer number and within individual mice. We calculate that approximately 20% of CD62L(high) cells convert to CD62L(low) during each division.
Project description:The peripheral Foxp3(+) Treg pool consists of naturally arising Treg (nTreg) and adaptive Treg cells (iTreg). It is well known that naive CD4(+) T cells can be readily converted to Foxp3(+) iTreg in vitro, and memory CD4(+) T cells are resistant to conversion. In this study, we investigated the induction of Foxp3(+) T cells from various CD4(+) T-cell subsets in human peripheral blood. Though naive CD4(+) T cells were readily converted to Foxp3(+) T cells with TGF-? and IL-2 treatment in vitro, such Foxp3(+) T cells did not express the memory marker CD45RO as do Foxp3(+) T cells induced in the peripheral blood of Hepatitis B Virus (HBV) patients. Interestingly, a subset of human memory CD4(+) T cells, defined as CD62L(+) central memory T cells, could be induced by TGF-? to differentiate into Foxp3(+) T cells. It is well known that Foxp3(+) T cells derived from human CD4(+)CD25(-) T cells in vitro are lack suppressive functions. Our data about the suppressive functions of CD4(+)CD62L(+) central memory T cell-derived Foxp3(+) T cells support this conception, and an epigenetic analysis of these cells showed a similar methylation pattern in the FOXP3 Treg-specific demethylated region as the naive CD4(+) T cell-derived Foxp3(+) T cells. But further research showed that mouse CD4(+) central memory T cells also could be induced to differentiate into Foxp3(+) T cells, such Foxp3(+) T cells could suppress the proliferation of effector T cells. Thus, our study identified CD4(+)CD62L(+) central memory T cells as a novel potential source of iTreg.