Triple Cytokine Research Articles

COVID-19 vaccinated children, adolescents, and young adults with acute lymphoblastic leukemia show spike reactive antibodies and multifunctional T-cells.

Little is known about the efficacy of COVID-19 vaccines during acute lymphoblastic leukemia therapy (ALL); data for COVID-19 vaccine immune responses in pediatric leukemia remain sparse. We conducted a single center study of patients aged 5-25 years undergoing ALL chemotherapy who received COVID-19 vaccination. Twenty-one patients were enrolled; efficacy was evaluable in 20. Twenty were vaccinated while receiving chemotherapy. Twenty received the BNT162b2 mRNA vaccine. Spike reactive antibodies (S-IgG) and/or T-cells (SRT) were detected in 16 of 20 (80%) vaccinated patients; 13 (65%) and 9 (45%) were positive for S-IgG and SRT, respectively. Six (30%) showed both spike reactive B and T-cell responses. Eleven of the 13 with S-IgG positivity were negative for anti-Nucleocapsid IgG, an antibody profile consistent with a vaccine induced immune response. All 13S-IgG+ patients showed neutralizing antibodies. SRT included CD4+ (7) and CD8+ (6) T-cells; both CD4+ and CD8+ SRT were seen in 4. SRT were multifunctional (producing multiple cytokines) in most patients (8 of 9); 4 showed SRT with triple cytokine and B-cell co-stimulatory responses, indicating a multimodal adaptive immune response. Immune responses were seen among patients vaccinated in the settings of lymphopenia (6 of 12) intensive chemotherapy (3 of 4), and Peg allergy (6 of 8). Sequencing revealed public CD4+ and CD8+ TCR sequences reactive to epitopes across the spike protein. In conclusion, COVID-19 vaccination induced B and/or T-cell responses in a majority of children and young adults undergoing ALL chemotherapy.

Rheumatoid arthritis synovial fluid shows enrichment of T-cells producing GMCSF which are polyfunctional for TNFα and IFNγ.

GMCSF+T-cells may be involved in pathogenesis of rheumatoid arthritis (RA), and polyfunctionality may be a marker of pathogenicity. Although, higher frequencies of CD4+GMCSF+ T-cells have been reported, there are no data on CD8+GMCSF+ T-cells or polyfunctionality.Our objective was to enumerate frequencies of CD8+GMCSF+ T cells in RA blood and synovial fluid (SF), and assess their polyfunctionality, memory phenotype and cytotoxic ability. This study included RA patients (blood samples,in some with paired synovial fluid (SF)), healthy controls (HC) (blood) and SpA patients (SF). In some RA patients' blood was sampled twice, before and 16-24 weeks after methotrexate (MTX) treatment. After mononuclear cell isolation from blood and SF, ex-vivo stimulation using PMA/Ionomycin was done, and cells were stained (surface and intracellular after permeabilisation/fixation). Subsequently, frequencies of GMCSF+CD8+ and CD4+ T-cells, polyfunctionality (TNFα, IFNγ, IL-17), phenotype (memory) and perforin/granzyme expression were assessed by flowcytometry. There was no significant difference in frequencies of GMCSF+CD8+ (3.7, 4.1%, p=0.540) or GMCSF+CD4+ T-cells (4.5, 5.2%, p=0.450) inblood of RA and HC. However, there was significant enrichment of both CD8+GMCSF+ (5.8, 3.9%, p=0.0045) and CD4+GMCSF+ (8.5, 4.5%, p=0.0008) T-cells inSF compared to blood in RA patients. Polyfunctional triple cytokine positive TNFα+IFNγ+GMCSF+CD8+T-cells (81, 36%, p=0.049) and CD4+T-cells (48, 32%, p=0.010) was also higher in SF compared to blood in RA. CD8+ T cells showed higher frequency of effector-memory phenotype and granzyme-B expression in RA-SF. On longitudinal follow-up, blood CD4+GMCSF+ T-cells significantly declined (4.6, 2.9%, p=0.0014) post-MTX. We report a novel finding of enrichment of CD8+GMCSF+ in addition to CD4+GMCSF+ T-cells in RA-SF. These cells showed higher polyfunctionality for TNFα and IFNγ, and effector memory phenotype suggesting their involvement in RA pathogenesis.

IL-21 from IFN-g +IL-21 +hybrid T cells promotes germinal center B cell proliferation

Abstract Clearance of infection with Plasmodium spp. requires both antibody and Th1-type responses. While Th1-like cells control the peak in P. chabaudi infection, however specific IgG is delayed. Both Tfh and GC-Tfh can promote specific antibodies and long-lived plasma cells to fully clear infection. GC-Tfh numbers remain stable throughout P. chabaudi infection, while Th1/Tfh hybrid (IFN-g +/IL-21 +CXCR5 int) cells expand. Testing if triple cytokine reporter mice (Il21-Kat Il4-GFP Ifng/Thy1.1 Knock-In) report Tfh functionality accurately, we confirmed that Tfh-like Il-21 +Ifng −cells were enriched for GC Tfh (CXCR5 hiPD-1 hiCXCR6 −) while the majority of Ifng +Il21 +cells were CXCR5 intCXCR6 +. GC-Tfh appear functional sooner than Ifng +Il21 +with expression of CCR7 intand Il4 +as early as day 5p.i. Transfer of cytokine-expressing subsets from triple reporter and Il21 −/−Ifng-Thy1.1 KI mice into T cell deficient recipients, which are then infected with P. chabaudi, also shows that Il21 +Ifng −Tfh-like cells from day 8 of P. chabaudi infection are functional. Il21 +Ifng −cell recipients generated more GC B cells, larger GCs and more parasite-specific IgG compared to other groups. Il21 +Ifng +hybrid T cells, also promoted GCs, but Th1-like Ifng +T cells from WT or Il21 −/−mice did not. As GCs were larger, but not more numerous, in Il21 +Ifng −recipient spleens, we hypothesized that B cell proliferation was increased. Indeed, there were more BrdU +dark zone (CXCR4 +CD86 −) GCB cells in recipients of Il21 +Ifng −cells than other groups, particularly recipients of Ifng +T cells from IL-21 KO. Combined, this data suggests that IL-21 from hybrid Th1/Tfh promotes GCB cells in vivo, though less than Il21 +Ifng −T cells. R01AI13506101

Enrichment of innate immune cells from PBMC followed by triple cytokine activation for adoptive immunotherapy.

Innate immune cells [Natural killer (NK) and gamma-delta (γδ) T-cells] have the advantage of mediating graft versus leukemia (GVL) without graft versus host disease (GVHD). Therefore, the infusion of activated innate immune cells post allogenic hematopoietic stem transplant (AHSCT) is a promising adoptive immunotherapy strategy for relapsed and/or refractory myeloid malignancies. Microbead depletion of T-cells and B-cells has been used as a graft manipulation method to prevent GVHD post haploidentical AHSCT. These grafts are enriched for NK and γδ T-cell receptor (TCR+) cells. Brief ex vivo activation of purified NK cells with interleukin (IL)-12, IL-18, and IL-15 [triple cytokines (TC)] has been shown to produce cells with a memory like function and significantly enhanced leukemia cytotoxicity. In our studies we depleted αβ TCR+ and CD19+ B-cells from healthy donors' peripheral blood mononuclear cells (PBMC) using microbeads; enriching the frequency of NK and γδ TCR+ cells. Following overnight TC incubation, we observed that these innate immune cells were activated based on phenotypic expression of CD69 and CD25. Further, we observed increased cytotoxicity of TC activated innate immune cells against NK sensitive and NK refractory leukemic cell targets. Further, the presence or absence of monocytes did not alter activation marker expression or in vitro cytotoxicity of innate immune cells. Additionally, we observed correlation between target cytotoxicity and mature activated NK phenotypes (CD56dim or CD56dim with co-expression of the activation markers CD69+ and/or CD25+). This approach of depleting T- and B-cells from PBMCs, combined with overnight TC activation, provides a novel cell population for donor lymphocyte infusion (DLI) post AHSCT.

Th1/Tfh hybrid (Ifng+Il21+) T cells contribute to delay of germinal center formation in Plasmodium chabaudi infection

Abstract Germinal center (GC) formation in P. chabaudi rodent malaria is delayed for three weeks, which can prolong the infection. T follicular helper (Tfh) cells express CXCR5 for homing to the B cell area, and IL-21 which promotes antibody production. T helper type 1 (Th1) cells express CXCR3 and IFN-γ to promote phagocytosis. Previous data suggests that Th1 responses control peak parasitemia while systemic Th1 cytokines inhibit GC formation. In P. chabaudi, majority of CD4+ effector T cells (Teff) express markers of both Th1 and Tfh (e.g., CXCR5, CXCR3, Th1/Tfh hybrid), including IFN-γ and IL-21. The contribution of Th1/Tfh hybrid T cells in protection and antibody production remains unclear. We tested the impact of Il21+Tfh-like, Ifng+Th1-like, and Ifng+Il21+Th1/Tfh in protection by transferring these subsets from infected triple cytokine reporters (Il21-rfp Il4-gfp Ifng-Thy1.1) into TCR KO mice that are then infected. We are currently assessing changes in parasitemia and pathology. We found that Th1/Tfh cells do not help in vivo like recent data suggest they do in vitro. Th1/Tfh significantly generated few GC B cells, compared to Il21+ Tfh-like cells. Recipients of Th1-like cells had significantly lower parasite-specific IgG and GCs by immunohistology than Tfh-like at 21 dpi, hybrid Th1/Tfh were intermediate. A cytokine kinetics study of Th subsets in infected cytokine reporter mouse distinguished Il4+Il21+ GC Tfh from Th1 cells. The inflammation-driven chemokine receptors CXCR3 and CXCR6 are highly expressed on GC Tfh and Th1/Tfh hybrid during the first week of infection, but decline as GCs develop, suggesting a role for T cell migration which could explain the delay in GC formation and parasite-specific antibody production in malaria. Supported by R01AI 135061

Tumor Necrosis Factor-α Mediates Lung Injury in the Early Phase of Endotoxemia.

Endotoxemia induces lung injury. We assessed the therapeutic efficacy between triple cytokine (tumor necrosis factor-α [TNF-α], interleukin-1β [IL-1β], and IL-6) inhibition (mediated by KCF18 peptide) and single cytokine (TNF-α) inhibition (mediated by SEM18 peptide) on alleviating lung injury in the early phase of endotoxemia. Mice receiving endotoxin (Endo group), endotoxin plus KCF18 (EKCF group), or endotoxin plus SEM18 (ESEM) were monitored and euthanized at 24 h after endotoxin. Our data demonstrated altered lung function (decreases in tidal volume, minute ventilation, and dynamic compliance; and by contrast, increases in airway resistance and end expiration work) and histology (increases in injury scores, leukocyte infiltration, vascular permeability, and tissue water content) in the Endo group with significant protection observed in the EKCF and ESEM groups (all p < 0.05). Levels of inflammation (macrophage activation and cytokine upregulations), oxidation (lipid peroxidation), necroptosis, pyroptosis, and apoptosis in EKCF and ESEM groups were comparable and all were significantly lower than in the Endo group (all p < 0.05). These data demonstrate that single cytokine TNF-α inhibition can achieve therapeutic effects similar to triple cytokines TNF-α, IL-1β, and IL-6 inhibition on alleviating endotoxin-induced lung injury, indicating that TNF-α is the major cytokine in mediating lung injury in the early phase of endotoxemia.

Role of IL-25, IL-33, and TSLP in triggering united airway diseases toward type 2 inflammation.

Under the concept of "united airway diseases," the airway is a single organ wherein upper and lower airway diseases are commonly comorbid. The upper and lower airways are lined with respiratory epithelium that plays a vital role in immune surveillance and modulation as the first line of defense to various infective pathogens, allergens, and physical insults. Recently, there is a common hypothesis emphasizing epithelium-derived cytokines, namely IL-25, IL-33, and TSLP, as key regulatory factors that link in immune-pathogenic mechanisms of allergic rhinitis (AR), chronic rhinosinusitis (CRS), and asthma, mainly involving in type 2 inflammatory responses and linking innate and adaptive immunities. Herein, we review studies that elucidated the role of epithelium-derived triple cytokines in both upper and lower airways with the purpose of expediting better clinical treatments and managements of AR, CRS, asthma, and other associated allergic diseases via applications of the modulators of these cytokines.

Th17-derived cytokines synergistically enhance IL-17C production by the colonic epithelium

Abstract Tightly regulated communication between the gastrointestinal (GI) epithelium and immune cells in the underlying lamina propria is critical for immune homeostasis. Interleukin (IL)-17C, produced by epithelial cells after exposure to inflammatory stimuli, facilitates cell-to-cell communication by promoting pro-inflammatory responses in Th17 cells. Since Th17-derived cytokines induce the expression of IL-17C, we hypothesize that IL-17C participates in an inflammatory amplification loop with Th17-derived cytokines, contributing to GI disease. We report that a Th17-derived cytokine TNFα induces IL-17C mRNA and protein expression in human colonic epithelial cell lines via an NFκB dependent pathway. Co-stimulation of TNFα-treated cells with Th17-derived IL-17A or IL-22 induces a respective 2,000- and 1,000-fold increase in IL-17C mRNA and protein. All three cytokines stimulate an 11,000-fold increase of IL-17C. While neither IL-17A nor IL-22 alone induce IL-17C synthesis, their presence at culture initiation is necessary to achieve synergy, suggesting that they stimulate the cells independently from TNFα. Inhibition of NFκB activation reduces IL-17C production by 99.99%, confirming that TNFα is the primary stimulant. Inhibition of AP-1 reduces IL-17C mRNA synthesis induced by pairwise or triple cytokine exposure to levels equivalent to that of TNFα alone, suggesting a role for this transcription factor in the synergistic response. IL-17A-mediated RNA stability was shown not to contribute to the mechanism of synergy. Taken together, cooperation between the NFκB and AP-1 signaling pathways in colonic epithelial cells may mediate the synergy observed in this novel pro-inflammatory feed-forward loop in the GI tract.

A single dose polyanhydride-based nanovaccine against paratuberculosis infection

Mycobacterium avium subsp. paratuberculosis (M. paratuberculosis) causes Johne’s disease in ruminants and is characterized by chronic gastroenteritis leading to heavy economic losses to the dairy industry worldwide. The currently available vaccine (inactivated bacterin in oil base) is not effective in preventing pathogen shedding and is rarely used to control Johne’s disease in dairy herds. To develop a better vaccine that can prevent the spread of Johne’s disease, we utilized polyanhydride nanoparticles (PAN) to encapsulate mycobacterial antigens composed of whole cell lysate (PAN-Lysate) and culture filtrate (PAN-Cf) of M. paratuberculosis. These nanoparticle-based vaccines (i.e., nanovaccines) were well tolerated in mice causing no inflammatory lesions at the site of injection. Immunological assays demonstrated a substantial increase in the levels of antigen-specific T cell responses post-vaccination in the PAN-Cf vaccinated group as indicated by high percentages of triple cytokine (IFN-γ, IL-2, TNF-α) producing CD8+ T cells. Following challenge, animals vaccinated with PAN-Cf continued to produce significant levels of double (IFN-γ, TNF-α) and single cytokine (IFN-γ) secreting CD8+ T cells compared with animals vaccinated with an inactivated vaccine. A significant reduction in bacterial load was observed in multiple organs of animals vaccinated with PAN-Cf, which is a clear indication of protection. Overall, the use of polyanhydride nanovaccines resulted in development of protective and sustained immunity against Johne’s disease, an approach that could be applied to counter other intracellular pathogens.

Myelin oligodendrocyte glycoprotein revisited—sensitive detection of MOG-specific T-cells in multiple sclerosis

Autoreactive CD4+ T-cells are believed to be a main driver of multiple sclerosis (MS). Myelin oligodendrocyte glycoprotein (MOG) is considered an autoantigen, yet doubted in recent years. The reason is in part due to low frequency and titers of MOG autoantibodies and the challenge to detect MOG-specific T-cells. In this study we aimed to analyze T-cell reactivity and frequency utilizing a novel method for detection of antigen-specific T-cells with bead-bound MOG as stimulant.Peripheral blood mononuclear cells (PBMCs) from natalizumab treated persons with MS (n = 52) and healthy controls (HCs) (n = 24) were analyzed by IFNγ/IL-22/IL-17A FluoroSpot. A higher number of IFNγ (P = 0.001), IL-22 (P = 0.003), IL-17A (P < 0.0001) as well as double and triple cytokine producing MOG-specific T-cells were detected in persons with MS compared to HCs. Of the patients, 46.2–59.6% displayed MOG-reactivity. Depletion of CD4+ T-cells or monocytes or blocking HLA-DR completely eliminated the MOG specific response. Anti-MOG antibodies did not correlate with T-cell MOG-responses.In conclusion, we present a sensitive method to detect circulating autoreactive CD4+ T-cells producing IFNγ, IL-22 or IL-17A using MOG as a model antigen. Further, we demonstrate that MOG-specific T-cells are present in approximately half of persons with MS.

Mycobacterial Lipoprotein Z Triggers Efficient Innate and Adaptive Immunity for Protection Against Mycobacterium tuberculosis Infection.

Mycobacterial lipoproteins are considered to be involved in both virulence and immunoregulatory processes during Mycobacterium tuberculosis (M.tb) infection. In our previous investigations on the immunoreactivity of more than 30 M.tb proteins in active TB patients, we identified mycobacterial lipoprotein Z (LppZ) as one of the most immune dominant antigens. How LppZ triggers immune responses is still unclear. In this study, we analyzed LppZ-mediated innate and adaptive immunity using a murine air pouch model and an M.tb infection model, respectively. We found that LppZ could not only recruit inflammatory cells but also induce the production of proinflammatory cytokines inside the pouches. LppZ could also induce strong Th1 responses following immunization and confer protection against challenge with M.tb virulent strain H37Rv at a similar level to BCG vaccination but with less pathological damage in the lungs. Furthermore, we revealed the presence of LppZ-specific functional CD4+ T cells in the lungs of the challenged mice that were capable of secreting double or triple cytokines, including IFN-γ, IL-2, and TNF-α. Our study thus demonstrates that LppZ is of strong immunogenicity during M.tb infection in both humans and mice and has the ability to trigger effective innate and cellular immunity. Considering the limitations of candidate antigens in the pipeline of TB vaccine development, LppZ-mediated immune protection against M.tb challenge in the mouse model implies its potential application in vaccine development.

Potential Role of Interleukin-25/Interleukin-33/Thymic Stromal Lymphopoietin-Fibrocyte Axis in the Pathogenesis of Allergic Airway Diseases.

Objective:Allergic airway diseases (AADs) are a group of heterogeneous disease mediated by T-helper type 2 (Th2) immune response and characterized with airway inflammation and remodeling, including allergic asthma, allergic rhinitis, and chronic rhinosinusitis with allergic background. This review aimed to discuss the abnormal epithelial-mesenchymal crosstalk in the pathogenesis of AADs.Data Sources:Articles referred in this review were collected from the database of PubMed published in English up to January 2018.Study Selection:We had done a literature search using the following terms “allergic airway disease OR asthma OR allergic rhinitis OR chronic sinusitis AND IL-25 OR IL-33 OR thymic stromal lymphopoietin OR fibrocyte”. Related original or review articles were included and carefully analyzed.Results:It is now believed that abnormal epithelial-mesenchymal crosstalk underlies the pathogenesis of AADs. However, the key regulatory factors and molecular events involved in this process still remain unclear. Epithelium-derived triple cytokines, including interleukin (IL)-25, IL-33, and thymic stromal lymphopoietin (TSLP), are shown to act on various target cells and promote the Th2 immune response. Circulating fibrocyte is an important mesenchymal cell that can mediate tissue remodeling. We previously found that IL-25-circulating fibrocyte axis was significantly upregulated in patients with asthma, which may greatly contribute to asthmatic airway inflammation and remodeling.Conclusions:In view of the redundancy of cytokines and “united airway” theory, we propose a new concept that IL-25/IL-33/TSLP-fibrocyte axis may play a vital role in the abnormal epithelial-mesenchymal crosstalk in some endotypes of AADs. This novel idea will guide potential new intervention schema for the common treatment of AADs sharing common pathogenesis in the future.

FGFR1 is essential for N-acetyl-seryl-aspartyl-lysyl-proline regulation of mitochondrial dynamics by upregulating microRNA let-7b-5p

Fibroblast growth factor receptor (FGFR) 1 plays a key role in endothelial homeostasis by inducing microRNA (miR) let-7. Our previous paper showed that anti-fibrotic effects of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) were associated with restoring diabetes-suppressed expression of FGFR1 and miR let-7, the key contributor of mitochondrial biogenesis, which is regulated by mitochondrial membrane GTPase proteins (MFN2 and OPA1). Here, we found that the FGFR1 signaling pathway was critical for AcSDKP in maintaining endothelial mitochondrial biogenesis through induction of miR let-7b-5p. In endothelial cells, AcSDKP restored the triple cytokines (TGF-β2, interleukin-1β, tumor necrosis factor-α)-suppressed miR let-7b-5p and protein levels of the mitochondrial membrane GTPase. This effect of AcSDKP was lost with either fibroblast growth factor receptor substrate 2 (FRS2) siRNA or neutralizing FGFR1-treated cells. Similarly, AcSDKP had no effect on the miR let-7b-5p inhibitor-suppressed GTPase levels in endothelial cells. In addition, a miR let-7b-5p mimic restored the levels of FRS2 siRNA-reduced GTPases in endothelial cells. These findings were also confirmed using MitoTracker Green and an immunofluorescence assay. Our results demonstrated that the AcSDKP-FGFR1 signaling pathway is critical for maintaining mitochondrial dynamics by control of miR let-7b-5p in endothelial cells.

Unique transcriptome signatures and GM-CSF expression in lymphocytes from patients with spondyloarthritis

Spondyloarthritis encompasses a group of common inflammatory diseases thought to be driven by IL-17A-secreting type-17 lymphocytes. Here we show increased numbers of GM-CSF-producing CD4 and CD8 lymphocytes in the blood and joints of patients with spondyloarthritis, and increased numbers of IL-17A+GM-CSF+ double-producing CD4, CD8, γδ and NK cells. GM-CSF production in CD4 T cells occurs both independently and in combination with classical Th1 and Th17 cytokines. Type 3 innate lymphoid cells producing predominantly GM-CSF are expanded in synovial tissues from patients with spondyloarthritis. GM-CSF+CD4+ cells, isolated using a triple cytokine capture approach, have a specific transcriptional signature. Both GM-CSF+ and IL-17A+GM-CSF+ double-producing CD4 T cells express increased levels of GPR65, a proton-sensing receptor associated with spondyloarthritis in genome-wide association studies and pathogenicity in murine inflammatory disease models. Silencing GPR65 in primary CD4 T cells reduces GM-CSF production. GM-CSF and GPR65 may thus serve as targets for therapeutic intervention of spondyloarthritis.

Role of lymphocytes producing GM-CSF in human spondyloarthritis

BackgroundThe spondyloarthritides (SpA) are immune-driven inflammatory diseases in which T lymphocytes are thought to have a major pathogenic role. Lymphocytes producing granulocyte-macrophage colony-stimulating factor (GM-CSF) have been shown to be especially pathogenic in murine models of SpA. This study aimed to identify and characterise the role of GM-CSF-producing lymphocytes in human SpA. MethodsPeripheral blood and joint-derived mononuclear cells from adults with SpA and controls (healthy adults and adults with the inflammatory joint disease rheumatoid arthritis) were studied with flow cytometry and time of flight mass cytometry (CyTOF). The role of GM-CSF was also investigated in joint-derived innate lymphoid cells. GM-CSF-producing CD4 lymphocytes were isolated by cytokine capture, and RNA sequencing transcriptomic analysis was used to compare GM-CSF lymphocytes with T helper (Th) 1 and Th17 cells. FindingsAn expansion of GM-CSF-producing CD4 and CD8 T cells was noted in the blood and joints of patients with SpA. Flow cytometry and CyTOF showed that CD4 T cells were the main producers of GM-CSF. GM-CSF production occurred both independently and in combination with classic Th1 and Th17 cytokines, with increased numbers of interleukin 17A+GM-CSF+ double-producing CD4, CD8, and natural killer cells. Expansion of type 3 innate lymphoid cells in SpA also occurred, and GM-CSF was abundantly produced by these cells. Transcriptional analysis of GM-CSF+ cells isolated with a novel triple cytokine capture approach suggested that human GM-CSF+ CD4 T cells represent an effector population distinct from Th1 and Th17 cells. InterpretationGM-CSF is a key effector cytokine in human SpA and may be a valid target for therapeutic intervention. Anti-GM-CSF monoclonal antibodies are currently in phase 3 trials for rheumatoid arthritis and have been shown to be safe in patients. These data would support the use of these antibodies in SpA. FundingWellcome Trust clinical PhD award (to MHA-M).

Abstract 4865: Metformin improves multiple cytokine producing ability of exhausted peripheral CD8+ T cells of cancer patients

Abstract Background: We have recently shown that metformin, a prescribed drug for type 2 diabetes, can increase the number of CD8+ tumor infiltrating lymphocytes (CD8+ TILs) that can produce triple cytokines, thus, IFN-ã, IL-2 and TNF-á in mouse models. Increased numbers of such multifunctional CD8+ TILs have well correlated with tumor retardation, suggesting an underlying mechanism of metformin in tumor immunity. In the current study, we examined the effects of direct exposure of metformin in vitro to CD8+ T cells of cancer patients. Methods: Peripheral blood mononuclear cells (PBMC) from cancer patients and healthy volunteers were obtained for the analysis. We cultured the PBMC with or without metformin overnight, followed by stimulation with phorbol 12-myristate 13-acetate (PMA) / ionomycin in vitro in various glucose concentrations for 6 hours. Expressions of markers for immune-check points (PD-1 and Tim-3) were examined together with accumulated intracellular cytokines, IFN-ã, IL-2 and TNF-á by flow cytometry analysis. Results: PD-1 and Tim-3 expressions of cancer patients’ PBMC were apparently higher than those of healthy volunteers’. Increased production of multiple cytokines was observed in CD8+ T cells of almost all cancer patients by metformin pretreatment, whereas no changes were detected in the samples from healthy volunteers. Moreover, deprivation of glucose clearly limited the production of cytokines on CD8 + T cells in a cancer patient. These results suggested patient’ CD8 + T cells showed lower activity of glycolysis compared with a healthy volunteer and metformin might stimulate glycolysis followed by reversion of mitochondrial respiration in exhausted CD8 + T cells. Conclusion: Metformin treatment might be useful in reversion of exhausted CD8+T cells in cancer bearing patients. Citation Format: Mototsugu Watanabe, Shingo Eikawa, Takenori Uehara, Yuki Kunisada, Shinichi Toyooka, Shinichiro Miyoshi, Heiichiro Udono. Metformin improves multiple cytokine producing ability of exhausted peripheral CD8+ T cells of cancer patients. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 4865.

IFNγ and IL-12 Restrict Th2 Responses during Helminth/Plasmodium Co-Infection and Promote IFNγ from Th2 Cells.

Parasitic helminths establish chronic infections in mammalian hosts. Helminth/Plasmodium co-infections occur frequently in endemic areas. However, it is unclear whether Plasmodium infections compromise anti-helminth immunity, contributing to the chronicity of infection. Immunity to Plasmodium or helminths requires divergent CD4+ T cell-driven responses, dominated by IFNγ or IL-4, respectively. Recent literature has indicated that Th cells, including Th2 cells, have phenotypic plasticity with the ability to produce non-lineage associated cytokines. Whether such plasticity occurs during co-infection is unclear. In this study, we observed reduced anti-helminth Th2 cell responses and compromised anti-helminth immunity during Heligmosomoides polygyrus and Plasmodium chabaudi co-infection. Using newly established triple cytokine reporter mice (Il4gfpIfngyfpIl17aFP635), we demonstrated that Il4gfp+ Th2 cells purified from in vitro cultures or isolated ex vivo from helminth-infected mice up-regulated IFNγ following adoptive transfer into Rag1–/– mice infected with P. chabaudi. Functionally, Th2 cells that up-regulated IFNγ were transcriptionally re-wired and protected recipient mice from high parasitemia. Mechanistically, TCR stimulation and responsiveness to IL-12 and IFNγ, but not type I IFN, was required for optimal IFNγ production by Th2 cells. Finally, blockade of IL-12 and IFNγ during co-infection partially preserved anti-helminth Th2 responses. In summary, this study demonstrates that Th2 cells retain substantial plasticity with the ability to produce IFNγ during Plasmodium infection. Consequently, co-infection with Plasmodium spp. may contribute to the chronicity of helminth infection by reducing anti-helminth Th2 cells and converting them into IFNγ-secreting cells.

Involvement of IL-18 in the expansion of unique hepatic T cells with unconventional cytokine profiles during Schistosoma mansoni infection.

Infection with schistosomes invokes severe fibrotic granulomatous responses in the liver of the host. Schistosoma mansoni infection induces dramatic fluctuations in Th1 or Th2 cytokine responses systemically; Th1 reactions are provoked in the early phase, whilst Th2 responses become dominant after oviposition begins. In the liver, various unique immune cells distinct from those of conventional immune competent organs or tissues exist, resulting in a unique immunological environment. Recently, we demonstrated that S. mansoni infection induces unique CD4+ T cell populations exhibiting unconventional cytokine profiles in the liver of mice during the period between Th1- and Th2-phases, which we term the transition phase. They produce both IFN-γ and IL-4 or both IFN-γ and IL-13 simultaneously. Moreover, T cells secreting triple cytokines IFN-γ, IL-13 and IL-4 were also induced. We term these cells Multiple Cytokine Producing Hepatic T cells (MCPHT cells). During the transition phase, when MCPHT cells increase, IL-18 secretion was up-regulated in the liver and sera. In S. mansoni-infected IL-18-deficient mice, expansion of MCPHT cells was curtailed. Thus our data suggest that IL-18 produced during S. mansoni infection play a role in the expansion of MCPHT cells.

IDO-Independent Suppression of T Cell Effector Function by IFN-γ–Licensed Human Mesenchymal Stromal Cells

Human bone marrow-derived mesenchymal stromal cells (MSCs) inhibit proliferation of activated T cells, and IFN-γ plays an important role in this process. This IFN-γ-licensed veto property is IDO-dependent. To further decipher the mechanistic underpinnings of MSC veto function on T cells, we investigated the effect of MSCs and IFN-γ-licensed MSCs on T cell effector function as assayed by cytokine secretion of T cells. Although MSCs and IFN-γ-licensed MSCs inhibit T cell proliferation, only IFN-γ-licensed MSCs significantly inhibit Th1 cytokine (IFN-γ, TNF-α, and IL-2) production by T cells. Additionally, IFN-γ-licensed MSCs inhibit T cell degranulation as well as single, double, and triple cytokine-producing T cells. Although IFN-γ-licensed MSCs upregulate their IDO activity, we found that MSC IDO catalytic function is dispensable with regard to MSC-driven inhibition of T cell effector function. Novel flow cytometry based functional screening of MSC-expressed, IFN-γ-licensed inhibitory molecules identified B7H1 and B7DC/PD1 pathways as essential effectors in blocking T cell function. Small interfering RNA-mediated blocking of B7H1 and B7DC reverses the inhibitory potential of IFN-γ-licensed MSCs on T cell effector function. Mechanistic analysis revealed that clustering of MHC and coinhibitory molecules are indispensable for the inhibitory effect of IFN-γ MSCs. Although exogenous IL-2 reverses B7H1-Ig-mediated inhibition of T cell proliferation, it does not affect the veto function of IFN-γ MSCs on both T cell proliferation and effector function. Our results reveal a new immunosuppressive property of IFN-γ-licensed MSCs that inhibits T cell effector function independent of IDO but through the ligands for PD1.

The Allo- and Viral-Specific Immunosuppressive Effect of Belatacept, but Not Tacrolimus, Attenuates With Progressive T Cell Maturation

Tacrolimus impairs allo- and viral-specific T cell responses. Belatacept, a costimulation-based alternative to tacrolimus, has emerged with a paradoxical picture of less complete control of alloimmunity with concomitant impaired viral immunity limited to viral-naïve patients. To reconcile these signatures, bulk population and purified memory and naïve lymphocytes from cytomegalovirus (CMV)-seropositive (n = 10) and CMV-seronegative (n = 10) volunteers were studied using flow cytometry, interrogating proliferation (carboxyfluorescein succinimidyl ester dilution) and function (intracellular cytokine staining) in response to alloantigens or CMV-pp-65 peptides. As anticipated, T cells from CMV-experienced, but not naïve, individuals responded to pp-65 with a small percentage of their repertoire (<2.5%) consisting predominantly of mature, polyfunctional (expressing interferon gamma, tumor necrosis factor alpha and IL-2) T effector memory cells. Both CMV naïve and experienced individuals responded similarly to alloantigen with a substantially larger percentage of the repertoire (up to 48.2%) containing proportionately fewer polyfunctional cells. Tacrolimus completely inhibited responses of CMV- and allo-specific T cells regardless of their maturation. However, belatacept’s effects were decreasingly evident in increasingly matured cells, with minimal effect on viral-specific triple cytokine producers and CD28-negative allo-specific cells. These data indicate that belatacept’s immunosuppressive effect, unlike tacrolimus’s, wanes on progressively developed effector responses, and may explain the observed clinical effects of belatacept.