scholarly journals Contribution of innate and adaptive immune cells to the elimination of Salmonella enterica serotype Enteritidis infection in young broiler chickens

2021 ◽  
Author(s):  
Nathalie Meijerink ◽  
Robin H.G.A. van den Biggelaar ◽  
Daphne A. van Haarlem ◽  
J. Arjan Stegeman ◽  
Victor P.M.G. Rutten ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Nk Cells ◽  
Salmonella Enterica ◽  
Broiler Chickens ◽  
Immune Modulation ◽  
Severe Disease ◽  
Antibody Responses ◽  
Adaptive Immune

AbstractSalmonella enterica serotype Enteritidis (SE) is a zoonotic pathogen which causes foodborne diseases in humans through contaminated poultry products, as well as severe disease symptoms in young chickens. More insight in innate and adaptive immune responses of chickens to SE infection is needed to understand elimination of SE. Seven-day-old broiler chickens were experimentally challenged with SE and numbers and responsiveness of innate immune cells including natural killer (NK) cells, macrophages and dendritic cells (DCs) were assessed during 21 days post-infection (dpi). In parallel, numbers and function of γδ T cells, CD8+ and CD4+ T cells as well as antibody titres were determined. SE was observed in the intestine and spleen of SE-infected chickens at 7 dpi. NK and T cells responded first to SE at 1 and 3 dpi as indicated by increased numbers of intestinal IL-2Rα+ and 20E5+ NK cells, in addition to enhanced activation of intestinal and splenic NK cells. At 7 dpi in the spleen, the presence of macrophages and the expression of activation markers on DCs was increased. At 21 dpi, an increase in intestinal γδ and CD8+ T cell numbers was observed. Furthermore, SE-specific proliferation of splenic CD4+ and CD8+ T cells was observed and SE-specific antibodies were detected in all blood samples of SE-infected chickens. In conclusion, SE results in enhanced numbers and activation of innate cells during early stages of infection and it is hypothesized that in concert with subsequent specific T cell and antibody responses, reduction of SE in infected chickens is achieved. A better understanding of innate and adaptive immune responses important in the elimination of SE will aid in developing immune-modulation strategies, which may increase resistance and prevent SE infection and colonization in young broiler chickens and hence increase food safety for humans.Author summarySalmonella enterica serotype Enteritidis (SE) causes foodborne zoonotic diseases in humans, as well as a severe disease in young chickens. As a consequence of which health and welfare of humans and chickens are affected, resulting in substantial economic losses. To enable development of immune-mediated prevention strategies in chickens, more insight in the immune responses to SE is needed to understand how the infection is eliminated. For this purpose, we investigated non-specific and specific immune responses upon experimental SE infection in young broiler chickens. In this study, we found SE in the intestine and spleen of SE-infected chickens at 7 days post-infection (dpi). We show that natural killer (NK) cells respond first by enhanced presence and activation, followed by increased presence of macrophages and activation of dendritic cells. These early responses are hypothesized to stimulate the observed subsequent specific T cell and antibody responses. Better understanding of immune responses important in the elimination of SE will aid in developing immune-modulation strategies, which may increase resistance and prevent SE infection and colonization in young chickens and hence reduce SE-related foodborne illness in humans.

scholarly journals A detailed analysis of innate and adaptive immune responsiveness upon infection with Salmonella enterica serotype Enteritidis in young broiler chickens

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Nathalie Meijerink ◽  
Robin H. G. A. van den Biggelaar ◽  
Daphne A. van Haarlem ◽  
J. Arjan Stegeman ◽  
Victor P. M. G. Rutten ◽  
...  
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
Nk Cells ◽  
Salmonella Enterica ◽  
Broiler Chickens ◽  
Immune Modulation ◽  
Adaptive Immune Responses ◽  
Activation Markers ◽  
Adaptive Immune ◽  
Adaptive Immune Cells

AbstractSalmonella enterica serotype Enteritidis (SE) is a zoonotic pathogen which causes foodborne diseases in humans as well as severe disease symptoms in young chickens. More insight in innate and adaptive immune responses of chickens to SE infection is needed to understand elimination of SE. Seven-day-old broiler chickens were experimentally challenged with SE and numbers and responsiveness of innate and adaptive immune cells as well as antibody titers were assessed. SE was observed in the ileum and spleen of SE-infected chickens at 7 days post-infection (dpi). At 1 dpi numbers of intraepithelial cytotoxic CD8+ T cells were significantly increased alongside numerically increased intraepithelial IL-2Rα+ and 20E5+ natural killer (NK) cells at 1 and 3 dpi. At both time points, activation of intraepithelial and splenic NK cells was significantly enhanced. At 7 dpi in the spleen, presence of macrophages and expression of activation markers on dendritic cells were significantly increased. At 21 dpi, SE-induced proliferation of splenic CD4+ and CD8+ T cells was observed and SE-specific antibodies were detected in sera of all SE-infected chickens. In conclusion, SE results in enhanced numbers and activation of innate cells and we hypothesized that in concert with subsequent specific T cell and antibody responses, reduction of SE is achieved. A better understanding of innate and adaptive immune responses important in the elimination of SE will aid in developing immune-modulation strategies, which may increase resistance to SE in young broiler chickens.

scholarly journals Innate immunity defines the capacity of antiviral T cells to limit persistent infection

2010 ◽  
Vol 207 (6) ◽  
pp. 1333-1343 ◽  
Author(s):  
Daniel M. Andrews ◽  
Marie J. Estcourt ◽  
Christopher E. Andoniou ◽  
Matthew E. Wikstrom ◽  
Andrea Khong ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Nk Cells ◽  
Viral Persistence ◽  
T Cell Responses ◽  
Cell Responses ◽  
Adaptive Immune ◽  
Acquired Immune Responses ◽  
Antigen Presenting

Effective immunity requires the coordinated activation of innate and adaptive immune responses. Natural killer (NK) cells are central innate immune effectors, but can also affect the generation of acquired immune responses to viruses and malignancies. How NK cells influence the efficacy of adaptive immunity, however, is poorly understood. Here, we show that NK cells negatively regulate the duration and effectiveness of virus-specific CD4+ and CD8+ T cell responses by limiting exposure of T cells to infected antigen-presenting cells. This impacts the quality of T cell responses and the ability to limit viral persistence. Our studies provide unexpected insights into novel interplays between innate and adaptive immune effectors, and define the critical requirements for efficient control of viral persistence.

scholarly journals P01.10 IFNy secretion of adaptive and innate immune cells as a parameter to display leukaemia derived dendritic cell (DCleu) mediated immune responses in AML

2020 ◽  
Vol 8 (Suppl 2) ◽  
pp. A13.1-A13
Author(s):  
LK Klauer ◽  
O Schutti ◽  
S Ugur ◽  
F Doraneh-Gard ◽  
N Rogers ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Cells ◽  
Gm Csf ◽  
Adaptive Immune ◽  
Cik Cells ◽  
Adaptive Immune Cells ◽  
Suitable Parameter

BackgroundMyeloid leukaemic blasts can be converted into leukaemia derived dendritic cells (DCleu) with blastmodulatory Kit-I and Kit-M, which have the competence to regularly activate T and immunoreactive cells to gain anti-leukaemic activity or rather cytotoxicity. As innate and adaptive immune responses are notably promoted by the cytokine interferon gamma (IFNy), we hypothesised that the IFNy secretion could be a suitable parameter to display DC/DCleu mediated immunologic activity and even anti-leukaemic cytotoxicity.Materials and MethodsDC/DCleu were generated from leukaemic WB with Kit-I (GM-CSF + OK-432) and Kit-M (GM-CSF + PGE1) and used to stimulate T cell enriched immunoreactive cells. Initiated anti-leukaemic cytotoxicity was investigated with a cytotoxicity fluorolysis assay (CTX). Initiated IFNy secretion of innate and adaptive immune cells (T cells, TCD4+ cells, TCD8+ cells, NKCD56+ cells, NKCD161+ cells, CIKCD56+ cells, CIKCD161+ cells and iNKT) was investigated with a cytokine secretion assay (CSA). In some cases IFNy production was additionally evaluated with an intracellular cytokine assay (ICA). Conclusively, the IFNy secretion of immunoreactive cells was correlated with the anti-leukaemic cytotoxicity.ResultsSignificant amounts of DC and DCleu as well as migratory DC and DCleu could be generated with Kit-I and Kit-M without induction of blast proliferation. T cell enriched immunoreactive cells stimulated with DC/DCleu showed an increased anti-leukaemic cytotoxicity and an increased IFNy secretion of T, NK and CIK cells compared to control. Both the CSA and ICA yielded comparable amounts of IFNy positive innate and adaptive immune cells. The correlation between the IFNy secretion of immunoreactive cells and the anti-leukaemic cytotoxicity showed a positive relationship in T cells, TCD4+ cells, TCD8+ cells and NKCD56+ cells.ConclusionsWe found blastmodulatory Kit-I and Kit-M competent to generate DC/DCleu from leukaemic WB. Stimulation of T cell enriched immunoreactive cells with DC/DCleu regularly resulted in an increased anti-leukaemic cytotoxicity and an increased IFNy dependent immunological activity of T, NK and CIK cells compared to control. Moreover the anti-leukaemic cytotoxicity positively correlated with the IFNy secretion in T cells, TCD4+ cells, TCD8+ cells, NKCD56+ cells. We therefore consider the IFNy secretion of innate and adaptive immune cells to be a suitable parameter to assess the efficacy of in vitro and potentially in vivo AML immunotherapy. The CSA in this regard proved to be a convenient and reproducible technique to detect and phenotypically characterise IFNy secreting cells of the innate and adaptive immune system.Disclosure InformationL.K. Klauer: None. O. Schutti: None. S. Ugur: None. F. Doraneh-Gard: None. N. Rogers: None. M. Weinmann: None. D. Krämer: None. A. Rank: None. C. Schmid: None. B. Eiz-Vesper: None. H.M. Schmetzer: None.

Investigating genes and micro-RNAs that may predict clinical benefits of anti-CTLA-4 therapy.

2013 ◽  
Vol 31 (15_suppl) ◽  
pp. 3043-3043
Author(s):  
Jianjun Gao ◽  
Hong Chen ◽  
Derek Ng Tang ◽  
Padmanee Sharma
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Modulation ◽  
Expression Profiles ◽  
Predictive Biomarkers ◽  
Rna Isolation ◽  
Complete Response ◽  
Micro Rnas ◽  
Clinical Benefits

3043 Background: Blockade of T cell co-inhibitory receptor CTLA-4 with a monoclonal antibody, ipilimumab, has led to augmented anti-tumor immune responses, clinical benefit, and FDA approval of ipilimumab for the treatment of metastatic melanoma. Only a subset of patients benefit from anti-CTLA-4 therapy. In order to identify genes, microRNAs, and signaling pathways that are modulated by anti-CTLA-4, which may be used for potential correlation with clinical outcomes or provide additional targets for therapy, we purified and analyzed CD4+T cells from patients treated with anti-CTLA-4 for changes in gene and microRNA expression profiles. Methods: On an IRB-approved phase Ia presurgical clinical trial, 6 patients with localized bladder cancer were treated with two doses of ipilimumab at 10 mg/kg at weeks 1 and 4. Pre-therapy and post-therapy blood samples were collected for CD4+ T cell enrichment by using the T cell isolation kit from Miltenyi Biotec (Auburn, CA). RNA and microRNA were isolated from purified CD4+T cells using Qiagen RNA isolation kits for Affymetrix microarray and micoRNA array analyses. Microarray data were then analyzed using Ingenuity iReport (Redwood City, CA). RT-PCR and Western blot were used to confirm significant changes in genes or pathways identified in microarray analyses. Results: Anti-CTLA-4 treatment resulted in modulation of differentially expressed genes (DEGs). After two doses of treatment, anti-CTLA-4 significantly changed expression of a total of 289 DEGs. Further pathway analyses indicated that anti-CTLA-4 induced a variety of pathways involved in cell proliferation and immune modulation, including PI3K/AKT, MAP/ERK, and IFN/JAK-STAT pathways. We have also identified 9 microRNAs that potentially regulate the expression of genes changed by anti-CTLA-4 therapy. Conclusions: Anti-CTLA-4 treatment results in modulation of multiple genes, microRNAs, and pathways, which likely play important roles in anti-tumor immune responses. We are currently testing a number of these identified genes and microRNAs as potential predictive biomarkers for anti-CTLA-4 therapy in a small cohort of patients who had complete response vs. progression of disease after anti-CTLA-4 therapy.

A study of genes and microRNAs that may predict clinical responses to anti-CTLA-4 therapy.

2013 ◽  
Vol 31 (6_suppl) ◽  
pp. 285-285
Author(s):  
Jianjun Gao ◽  
Hong Chen ◽  
Derek Ng Tang ◽  
Padmanee Sharma
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Immune Modulation ◽  
Expression Profiles ◽  
Predictive Biomarkers ◽  
Rna Isolation ◽  
Complete Response ◽  
Expression Of Genes ◽  
Pathway Analyses

285 Background: Blockade of T cell co-inhibitory receptor CTLA-4 with a monoclonal antibody, Ipilimumab (BMS), has led to augmented anti-tumor immune responses, clinical benefit, and FDA approval of Ipilimumab for the treatment of metastatic melanoma. Only a subset of patients benefit from anti-CTLA-4 therapy. In order to identify genes, microRNAs, and signaling pathways that are modulated by anti-CTLA-4, which may be used for potential correlation with clinical outcomes or provide additional targets for therapy, we purified and analyzed CD4+ T cells from patients treated with anti-CTLA-4 for changes in gene and microRNA expression profiles. Methods: On an IRB-approved Phase Ia presurgical clinical trial, 6 patients with localized bladder cancer were treated with two doses of Ipilimumab at 10 mg/kg at weeks 1 and 4. Pre-therapy and post-therapy blood samples were collected for CD4+ T cell enrichment by using the T cell isolation kit from Miltenyi Biotec (Auburn, CA). RNA and microRNA were isolated from purified CD4+ T cells using Qiagen RNA isolation kits for Affymetrix microarray and micoRNA array analyses. Microarray data were then analyzed using Ingenuity iReport (Redwood City, CA). RT-PCR and Western blot were used to confirm significant changes in genes or pathways identified in microarray analyses. Results: Ipilimumab treatment resulted in modulation of differentially expressed genes (DEGs). After two doses of treatment, Ipilimumab significantly changed expression of a total of 289 DEGs. Further pathway analyses indicated that Ipilimumab induced a variety of pathways involved in cell proliferation and immune modulation, including PI3K/AKT, MAP/ERK, and IFN/JAK-STAT pathways. We have also identified 9 microRNAs that potentially regulate the expression of genes changed by anti-CTLA-4 therapy. Conclusions: Ipilimumab treatment results in modulation of multiple genes, microRNAs, and pathways, which likely play important roles in anti-tumor immune responses. We are currently testing a number of these identified genes and microRNAs as potential predictive biomarkers for anti-CTLA-4 therapy in a small cohort of patients who had complete response vs. progression of disease after anti-CTLA-4 therapy.

scholarly journals T- and B-Cell Immune Responses of Patients Who Had Undergone Colectomies to Oral Administration of Salmonella enterica Serovar Typhi Ty21a Vaccine

2003 ◽  
Vol 10 (3) ◽  
pp. 426-430 ◽  
Author(s):  
Jan Kilhamn ◽  
Samuel B. Lundin ◽  
Hans Brevinge ◽  
Ann-Mari Svennerholm ◽  
Marianne Jertborn
Keyword(s):  
T Cells ◽  
Immune Responses ◽  
B Cell ◽  
Healthy Volunteers ◽  
Vaccine Strain ◽  
Salmonella Enterica ◽  
Antibody Responses ◽  
Igg Antibody ◽  
Iga Antibody ◽  
Ifn Γ

ABSTRACT The capacity of an oral live attenuated Salmonella enterica serovar Typhi Ty21a vaccine to induce immune responses in patients who had undergone colectomies because of ulcerative colitis was evaluated, and these responses were compared with those of healthy volunteers. Purified CD4+ and CD8+ T cells from peripheral blood were stimulated in vitro by using the heat-killed Ty21a vaccine strain, and the proliferation and gamma interferon (IFN-γ) production were measured before and 7 or 8 days after vaccination. Salmonella-specific immunoglobulin A (IgA) and IgG antibody responses in serum along with IgA antibody responses in ileostomy fluids from the patients who had undergone colectomies were also evaluated. Three doses of vaccine given 2 days apart failed to induce proliferative T-cell responses in all the six patients who had undergone colectomies, and increases in IFN-γ production were found only among the CD8+ cells from three of the patients. In contrast, both proliferative responses and increased IFN-γ production were observed among CD4+ and CD8+ T cells from 3 and 6 of 10 healthy volunteers, respectively. Salmonella-specific IgA and/or IgG antibody responses in serum were observed for five (56%) of nine patients who had undergone colectomies and in 15 (88%) of 17 healthy volunteers. In ileostomy fluids, significant anti-Salmonella IgA antibody titer increases were detected in six (67%) of nine patients who had undergone colectomies. The impaired T- and B-cell immune responses found after vaccination in the circulation of patients who have undergone colectomies may be explained by a diminished colonization of the Ty21a vaccine strain due to the lack of a terminal ileum and colon.

scholarly journals Oncogenic-Drivers Dictate Immune Responses to Control Disease Progression in Acute Myeloid Leukaemia

Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 904-904
Author(s):  
Rebecca Austin ◽  
Megan Bywater ◽  
Jasmin Straube ◽  
Leanne T Cooper ◽  
Madeleine Headlam ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Immune Responses ◽  
Nk Cells ◽  
Research Funding ◽  
T Cell Subsets ◽  
Transcriptional Analysis ◽  
Immune Control ◽  
Immune Microenvironment ◽  
Ifn Γ

Abstract Immunotherapy has revolutionised therapeutic approaches to fight cancer and, in certain diseases dramatically improves survival. Clinical responses to immune checkpoint blockade have in part been attributed to high mutational burden of tumours such as melanoma. High-risk acute myeloid leukaemia (AML) is defined by molecular and cytogenetic factors. AML has a low prevalence of somatic mutations and is predicted to have low immunogenicity. We aimed to determine how AMLs driven from different classes of oncogenes interact with endogenous anti-leukemic immune responses. Methods and Results We generated three oncogenically distinct models of AML: BCR-ABL+NUP98-HOXA9 (BA/NH9), MLL-AF9 (MA9), and AML1-ETO+NRASG12D (AE/NRAS), using retroviral transduced bone marrow transplanted into immune-competent, non-irradiated C57BL/6J (B6) mice or immune-deficient Rag2-/-γc-/- mice. Immunologic control of AML was dependent on the driver oncogene, as AE/NRAS AML was effectively controlled in B6, but not Rag2-/-γc-/-recipients, whereas survival of BA/NH9 AML recipients was similar between B6 and Rag2-/-γc-/-. MA9 AML had an intermediate phenotype (Figure 1A-C). To examine the mechanisms underlying immune escape in AE/NRAS, AML from immune-deficient or immune-competent hosts, was passaged through immune-competent hosts. Prior exposure to an intact immune system dramatically accelerated disease progression of AE/NRAS AML in subsequent B6 recipients, but this was not seen in passage through Rag2-/-γc-/- recipients. This demonstrates specific, functional immunoediting of AML resulting in evasion of immune control. Despite evidence of disease attenuation in immune competent hosts, functional immunoediting was not observed in MA9 AML. Antibody-mediated immune cell depletion experiments demonstrated that natural killer (NK) cells and T cells both contribute to the control AE/NRAS AML, whereas MA9 immune control was dependent on NK cells. As immunoediting was only seen in AE/NRAS model, this suggests that functional immunoediting in this model is primarily mediated by T cells. To characterise the mechanisms regulating immunoediting, we integrated proteomic and transcriptional analysis of immunoedited and non-immunoedited AE/NRAS AML. There was strong correlation between increased protein expression and transcriptional regulation. There was distinct regulation of inflammatory pathways between immunoedited and non-immunoedited AML. Immunoedited AE/NRAS cells showed increased IFN-γ-dependent response signatures, consistent with direct targeting of the leukemic cells by the immune system. Transcriptional analysis also showed modulation of expression of immune checkpoint molecules including upregulation of suppressive molecules Tim-3 and CD39 and downregulation of activating ligand CD137L. These findings were confirmed by cell-surface flow cytometry. Immunoedited AE/NRAS downregulated RAS signalling transcriptionally, with coordinate activation of MYC targets. In the murine AE/NRAS model, CD4+ and CD8+ T effector memory (TEM) cells (CD44+ CD62L-) demonstrated increased PD-1 expression compared to naïve mice. In addition, mice with high disease burden also had increased frequency of T cells co-expressing exhaustion markers PD-1, Tim-3 and LAG-3, consistent with suppression of the anti-leukemic effector immune response. To understand if these findings were relevant to AML in the clinic, we obtained single cell RNA-sequencing data from the CD45+ CD34- non-leukemic fraction of bone marrow in a patient with AML1-ETO AML at diagnosis compared to that in normal marrow. Single cell type classification and clustering using tSNE demonstrated remodelling of the immune microenvironment in AML with loss of NK cells, pre-B cells and skewing of T cell subsets. There was depletion of CD8+ TEM cells and greater proportions of CD4+ and CD8+ TEM cells expressing activation and exhaustion markers (IFN-γ, PD-1, LAG-3, TIM-3). Conclusions These data demonstrate that immune responses in AML are oncogene-specific and provide evidence that AE/NRAS AML cells undergo immunoediting over time in the presence of a competent immune microenvironment. Since AML is associated with alterations in T cell subsets, and changes in T cell activation and exhaustion states, these findings may inform translational strategies to use immunotherapies for patients with AML. Disclosures Smyth: Bristol Myers Squibb: Other: Research agreement; Tizona Therapeutics: Research Funding. Lane:Janssen: Consultancy, Research Funding; Celgene: Consultancy; Novartis: Consultancy.

scholarly journals Compartmentalized lymph node drainage dictates intestinal adaptive immune responses

2018 ◽  
Author(s):  
Daria Esterházy ◽  
Maria CC Canesso ◽  
Paul A Muller ◽  
Ainsley Lockhart ◽  
Luka Mesin ◽  
...  
Keyword(s):  
T Cell ◽  
Immune Responses ◽  
Immune Modulation ◽  
Specific Antigen ◽  
Cell Polarization ◽  
Food Allergies ◽  
Surgical Removal ◽  
Gastrointestinal Infections ◽  
Adaptive Immune ◽  
Intestinal Immune System

The intestinal immune system has the challenging task of tolerating foreign nutrients and the commensal microbiome, while excluding or eliminating ingested pathogens. Failure in such balance leads to a range of severe intestinal and systemic diseases such as inflammatory bowel diseases, food allergies or invasive gastrointestinal infections1,2. Multiple innate and adaptive immune mechanisms are therefore in place to maintain tissue integrity, including efficient peripheral generation of effector T (TH) cells and FOXP3+ regulatory T (pTreg) cells, which mediate resistance to pathogens and regulate excessive immune activation, respectively2–5. The gut-draining mesenteric lymph nodes (mLNs) are critical sites for orchestrating adaptive immunity to luminal perturbations6–8. However, how they manage to simultaneously support tolerogenic and inflammatory reactions is incompletely understood. Here we report that individual mLNs are anatomically and immunologically distinct according to the functional gut segment they drain. Dendritic cell gene signatures and adaptive T cell polarization against the same luminal antigen differed between mLNs along the intestine, the proximal small intestine–draining mLNs preferentially giving rise to tolerogenic and the distal mLNs to pro-inflammatory T cell responses. This compartmentalized dichotomy could be perturbed by duodenal infection, surgical removal of select distal mLNs, dysbiosis, or ectopic antigen delivery, impacting both lymphoid organ and tissue immune responses. Our findings reveal that the conflict between tolerogenic and inflammatory adaptive responses is in part resolved by discrete mLN drainage, and encourage gut segment-specific antigen targeting for therapeutic immune modulation.

Chronic Lymphocytic Leukemia Cells Acquire a Regulatory B-Cell Phenotype Modified By PD1 Signaling

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3319-3319 ◽  
Author(s):  
Shimrit Ringelstein-Harlev ◽  
Irit Avivi ◽  
Shoham Shivtiel-Arad ◽  
Tami Katz
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
T Cell ◽  
B Cells ◽  
Immune Responses ◽  
B Cell ◽  
Immune Modulation ◽  
Lymphocytic Leukemia ◽  
T Cell Proliferation ◽  
Cell Contact

Abstract Introduction: Chronic lymphocytic leukemia (CLL) cells utilize several mechanisms of survival, some propagating proliferation and preventing apoptosis through intrinsic cell cycle signals, and others suppressing anti-tumor immune responses. Patients often present with a predominant population of regulatory T-cells (Tregs), and general features of T-cell exhaustion. Given the unique phenotype of CLL cells and the observed T-cell abnormalities we hypothesized that these cells function as regulatory B-cells (Bregs). Bregs, mostly explored in the autoimmune disease setting, produce interleukin-10 (IL10), which mediates attenuation of effector T-cell responses and enhances regulatory activity. These features have also been suggested to be responsible for weakening of anti-tumor immune responses. Breg activation requires stimulation of various combinations of Toll-like receptors (TLRs), the B-cell receptor (BCR) and CD40. Our previous studies have demonstrated that TLR9-stimulated CLL cells "acquire" Breg markers as well as PD1 and PDL1, which, while not being classic Breg discriminators, are established players in immune modulation. Moreover, such stimulation resulted in inhibition of proliferation of autologous T-cells. The current study aimed to further explore the regulatory characteristics of CLL cells focusing on additional suppressive mechanisms that may have a role in CLL immune evasion, particularly, the PD1/PDL1 axis. Methods: B-cells were isolated from peripheral blood mononuclear cells (PBMCs) of untreated CLL patients (Rai stages 0-IV). These B-CLL cells were stimulated with TLR-9 agonist (ODN) or CD40 ligand (CD40L) followed by their co-culture with isolated autologous CD4+ T cells. The regulatory features of B-CLL cells were studied by testing their effect on T cells. Their proliferation was evaluated using the CFSE method following stimulation with anti-CD3/CD28 antibodies and IL2; induction of Tregs (CD4+CD25highFoxp3+ population) was assessed by FACS analysis. The involvement of the PD1/PDL1 axis was examined by incubating B-cells with antiPD1 neutralizing antibodies prior to co-culture. Cell contact dependence was evaluated by plating B-cells in hanging cell culture inserts denying B and T cell contact while allowing flow of small soluble molecules. Results: CLL cells stimulated with ODN or CD40L, induced a significant increase in Tregs: 1.35±0.1-fold (p=0.03, N=12) for ODN and 1.7±0.2-fold (p=0.008, N=14) for CD40L, occurring in 68% and 80% of patients, respectively, while co-culture with unstimulated B-CLL cells did not result in the expansion of the Treg population. Treg induction was observed only under contact conditions (N=5), suggesting that this regulatory function requires cell-to-cell contact and cannot be carried out solely by secreted factors like IL10. Neutralization of PD1 on CLL B-cells affects both Treg induction and T-cell proliferation. Following CD40L stimulation, a 1.3-fold reduction in Treg percentage was observed when PD1 signaling was blunted (N=10). In contrast, PD1 blockage of ODN-stimulated CLL cells did not reduce Treg induction; however, it did adversely affect inhibition of T-cell proliferation (10%-decrease in inhibited T-cells; N=6). Conclusions: CLL cells "acquire" a Breg phenotype and function, inhibiting T-cell proliferation and inducing Tregs. These properties, while working together to promote immune regulation and cancer evasion, are elicited by different ligands in the cell environment and are likely to be mediated via separate pathways. The involvement of B-cell-associated PD1 in the induction of Tregs and inhibition of T-cell proliferation suggests a biologic role of PD1 signaling in CLL cells, strengthening the Breg phenotype. The current study has shown that CLL cells recruit several mechanisms operating cooperatively to support immune modulation and promote their survival. Disclosures No relevant conflicts of interest to declare.

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