Frequency Of IFN-γ Research Articles

IRF3 deficiency contributes to impaired memory T cell function in response to influenza infection (IRM14P.453)

Abstract The role of IRF3 in initiating the type I interferon response in innate immune cells has been well studied in the context of viral infection. However, it remains unclear what impact IRF3 has in shaping and maintaining adaptive immune responses. To address this, IRF3 deficient (IRF3 KO) mice were infected with influenza A virus (IAV) and T cell responses measured. At day 9 post infection, the frequency of IFN-γ and Granzyme B (GrB) positive T cells were similar between IRF3 KO and wildtype mice. Despite similar primary responses, IRF3 KO mice exhibited significant deficits in recall memory T cell responses to IAV with reduced expression of IFN-γ and GrB. Since IRF3 has been implicated in the expression of cytokines that influence effector and memory T cells responses, cytokine supplementation studies were performed. Addition of IL-12 was the only cytokine tested that was able to rescue the IFN-γ deficiencies in IRF3 KO T cells. Interestingly, peptide specific GrB re-expression could not be restored by any cytokines tested. These results suggest that IRF3 plays a role in the maintenance of antigen specific memory T cell responses and that IRF3 deficiency has a substantial impact on the cytotoxic potential of memory T cells and recall responses. Together, this work provides further insight into the molecular regulation of adaptive immune responses to viral infections and may serve to inform future vaccine strategies that require the development of memory T cells.

Malaria DNA vaccine gp96NTD-CSP elicits both CSP-specific antibody and CD8(+) T cell response.

It is ideal for the pre-erythrocytic stage subunit vaccine to induce both CSP-specific antibody and CD8(+) T cell response. Here, we designed a novel malaria DNA vaccine gp96NTD-CSP, which was constructed by fusing the full-length of CSP with the N-terminal domain of gp96 that deleted the endoplasmic reticulum-localized motif KDEL, and investigated its protective efficacy. We found that the fusion protein gp96NTD-CSP was mainly distributed on the surface of eukaryotic cells after transfection and could be sensed as a "danger signal" by the host immune system. Interestingly, both liver parasite burden and parasitemia in mice immunized with gp96NTD-CSP were significantly lower than those in the mice immunized either with gp96NTD, CSP, or gp96NTD-SYVPSAEQI, which was constructed by fusing the CSP-specific CD8(+) T cell epitope with the N-terminal domain of gp96 deleted with KDEL. Consistently, both the level of CSP-specific antibody and the frequency of IFN-γ secreted-CSP-specific CD8(+) T cells were much higher in mice immunized with gp96NTD-CSP than those in the mice immunized either with gp96NTD, CSP, or gp96NTD-SYVPSAEQI. Our results suggest that the malaria DNA vaccine gp96NTD-CSP could induce both humoral and cellular immune responses, which is attributed to the adjuvant effect of gp96NTD and full-length CSP.

Severe atopic dermatitis is characterized by selective expansion of circulating TH2/TC2 and TH22/TC22, but not TH17/TC17, cells within the skin-homing T-cell population

Past studies of blood T-cell phenotyping in patients with atopic dermatitis (AD) have provided controversial results and were mostly performed before the identification of TH9, TH17, and TH22 T-cell populations in human subjects. We sought to quantify TH1, TH2, TH9, TH17, and TH22 T-cell populations and corresponding CD8(+) T-cell subsets in both cutaneous lymphocyte antigen (CLA)-positive and CLA(-) T-cell subsets in patients with AD and control subjects. We studied 42 adults with severe AD (mean SCORAD score, 65) and 25 healthy subjects using an 11-color flow cytometric antibody panel. Frequencies of IFN-γ-, IL-22-, IL-13-, IL-17-, and IL-9-producing CD4(+) and CD8(+) T cells were compared in CLA(-) and CLA(+) populations. We measured increased TH2/TC2/IL-13(+) and TH22/TC22/IL-22(+) populations (P < .1) in patients with severe AD versus control subjects, with significant differences in CLA(+) T-cell numbers (P < .01). A significantly lower frequency of CLA(+) IFN-γ-producing cells was observed in patients with AD, with no significant differences in CLA(-) T-cell numbers. The CLA(+) TH1/TH2 and TC1/TC2 ratio was highly imbalanced in patients with AD (10 vs 3 [P = .005] and 19 vs 7 [P < .001], respectively). Positive correlations were found between frequencies of IL-13- and IL-22-producing CD4(+) and CD8(+) T cells (r = 0.5 and 0.8, respectively; P < .0001), and frequencies of IL-13-producing CLA(+) cells were also correlated with IgE levels and SCORAD scores. Patients with AD with skin infections had higher CD4(+) IL-22(+) and IL-17(+) cell frequencies, which were highly significant among CLA(-) cells (IL-22: 3.7 vs 1.7 [P < .001] and IL-17: 1.7 vs 0.6 [P < .001]), with less significant effects among CLA(+) T cells (IL-22: 11 vs 7.5, P = .04). Severe AD is accompanied by expansion of skin-homing TH2/TC2 and TH22/TC22 subsets with lower TH1/TC1 frequencies. These data create a critical basis for studying alterations in immune activation in adults and pediatric patients with AD.

Human Umbilical Cord Mesenchymal Stem Cells Inhibit the Function of Allogeneic Activated Vγ9Vδ2 T Lymphocytes In Vitro.

Background. Human umbilical cord mesenchymal stem cells (UC-MSCs) can regulate the function of immune cells. However, whether and how UC-MSCs can modulate the function of Vγ9Vδ2 T cells has not been fully understood. Methods. The PBMCs or Vγ9Vδ2 T cells were activated and expanded with pamidronate (PAM) and interleukin-2 (IL-2) with or without the presence UC-MSCs. The effects of UC-MSCs on the proliferation, cytokine expression, and cytotoxicity of Vγ9Vδ2 T cells were determined by flow cytometry. The effects of UC-MSCs on Fas-L, TRAIL-expressing Vγ9Vδ2 T cells, and Vγ9Vδ2 T cell apoptosis were determined by flow cytometry. Results. UC-MSCs inhibited Vγ9Vδ2 T cell proliferation in a dose-dependent but cell-contact independent manner. Coculture with UC-MSCs reduced the frequency of IFNγ+ but increased granzyme B+ Vγ9Vδ2 T cells. UC-MSCs inhibited the cytotoxicity of Vγ9Vδ2 T cells against influenza virus H1N1 infected A549 cells and also reduced the frequency of Fas-L+, TRAIL+ Vγ9Vδ2 T cells but failed to modulate the apoptosis of Vγ9Vδ2 T cells. Conclusions. These results indicated that UC-MSCs efficiently suppressed the proliferation and cytotoxicity of Vγ9Vδ2 T cells and modulated their cytokine production. Fas-L and TRAIL were involved in the regulation. Cell contact and apoptosis of Vγ9Vδ2 T cells were not necessary for the inhibition.

Heteroclitic XBP1 peptides evoke tumor-specific memory cytotoxic T lymphocytes against breast cancer, colon cancer, and pancreatic cancer cells

XBP1 is a critical transcriptional activator of the unfolded protein response (UPR), which increases tumor cell survival under prolonged endoplasmic reticulum (ER) stress and hypoxic conditions.This study was designed to evaluate the immunogenicity of heteroclitic XBP1 unspliced (US)184–192 (YISPWILAV) and heteroclictic XBP1 spliced (SP)367–375 (YLFPQLISV) HLA-A2 peptides, and to characterize the specific activities of XBP1 peptides-specific cytotoxic T lymphocytes (XBP1-CTL) against breast cancer, colon cancer, and pancreatic cancer cells.The XBP1-CTL had upregulated expression of critical T cell markers and displayed HLA-A2-restricted and antigen-specific activities against breast cancer, colon cancer and pancreatic cancer cells. XBP1-CTL were enriched withCD45RO+ memory CTL, which showed high expression of critical T cell markers (CD28, ICOS, CD69, CD40L), cell proliferation and antitumor activities as compared to CD45RO− non-memory CTL. The effector memory (EM: CD45RO+CCR7−) subset had the highest level of cell proliferation while the central memory (CM: CD45RO+CCR7+) subset demonstrated enhanced functional activities (CD107a degranulation, IFNγ/IL-2 production) upon recognition of the respective tumor cells. Furthermore, both the EM and CM XBP1-CTL subsets expressed high levels of Th1 transcription regulators Tbet and Eomes. The highest frequencies of IFNγ or granzyme B producing cells were detected within CM XBP1-CTL subset that were either Tbet+ or Eomes+ in responding to the tumor cells.These results demonstrate the immunotherapeutic potential of a cocktail of immunogenic HLA-A2 specific heteroclitic XBP1 US184–192 and heteroclictic XBP1 SP367–375 peptides to induce CD3+CD8+ CTL enriched for CM and EM cells with specific antitumor activities against a variety of solid tumors.

A High Frequency of Peripheral Blood IL-22(+) CD4(+) T Cells in Patients With New Onset Type 2 Diabetes Mellitus.

This study is aimed at investigating the frequency of different functional IL-22(+) CD4(+) T cells in Chinese patients with type 2 diabetes mellitus (T2DM). The frequency of circulating IFN-γ+IL-17-IL-22-CD4(+) (Th1), IFN-γ-IL-17A+IL-22-CD4(+) (Th17), and IFN-γ-IL-17A-IL-22(+) CD4(+) (Th22), and other subsets of IL-22(+) CD4(+) T cells in 31 patients with new onset T2DM and 16 healthy controls was characterized by flow cytometry. The levels of serum IL-22, IL-17, IFN-γ, insulin C-peptide, hemoglobin A1c (HbA1c), fasting plasma glucose, and insulin were examined. The frequency of Th1, Th17, Th22, IFN-γ(+) IL-17(-) IL-22(+) , and IFN-γ(-) IL-17(+) IL-22(+) CD4(+) T cells and the concentrations of IL-22, but not IL-17 and IFNγ, in the patients were significantly higher than controls. The percentages of Th22 cells were correlated positively with the frequency of IFN-γ(-) IL-17(+) IL-22(+) CD4(+) T cells, the values of body mass index (BMI) and homeostatic model assessment insulin resistance (HOMA-IR), and the levels of serum IL-22 in those patients. Our data suggest that IL-22(+) CD4(+) T cells may contribute to the early process of T2DM.

IT-27 * ONCOLYTIC ADENOVIRUSES-MEDIATED IMMUNE RESPONSES IN SYNGENEIC MURINE GLIOMA MODEL

INTRODUCTION: Oncolytic adenovirus has been developed as a new experimental anticancer agent currently in clinical trials for glioma. Recent evidence suggests oncolytic viruses also have a therapeutic feature of inducing antitumor immune responses. Here we provide evidence that injection of oncolytic adenoviruses into established murine glioma leads to a conversion of immunosuppressive into immunostimulatory tumor environment. METHODS: Stereotactic orthotopic murine GL261 glioma was established in syngeneic immune competent mice. AdCMVΔ24 virus that has been shown to exhibit oncolytic effects on GL261 cells previously by our group was selected in the current studies. Using GL261 murine glioma model along with AdCMVΔ24, we evaluated the effects of viral treatment on generation of immune responses locally (in brain) and systemically (in cervical lymph nodes (cLNs) and spleens) upon viral injection into tumors. RESULTS: At 72hr post treatment, we observed a significant intracranial increase of both macrophages and NK cells. More importantly, we found that AdCMVΔ24 treatment decreased intracranial regulatory T cells (CD4+Foxp3+) at 72hr, 1 week, even at 2 weeks post viral treatment, whereas this was not observed in cLNs and spleens. In contrast to Treg cells, the frequency of CD3+CD8+ T cells were increased at 1 week and 2 weeks post treatment. We also found an increased frequency of IFN-g producing CD8+ cells, in cLNs as early as at 72hr and in brains at 2 weeks post treatment. Further, our studies demonstrated that intratumoral viral injection leads an increase of a ratio of CD4+IFN-g+T cells per CD4+Foxp3+ T cells. CONCLUSIONS: Taken together, these results suggest that intratumoral oncolytic adenovirus treatment may shift the immune response from suppressive to stimulatory through modulation of Treg cells, which could have significant impacts on the development of CRADs-based novel effective antiglioma immunotherapies.

Abstract 2894: Novel heteroclitic XBP1 peptides induce antigen-specific memory CD3+CD8+ T cells expressing critical T cell markers and transcription regulators

Abstract Background: XBP1 is a critical transcriptional activator of the unfolded protein response that enables tumors to survive prolonged endoplasmic reticulum stress due to nutrient deprivation, hypoxia or accumulation of unfolded/misfolded proteins. This provided us a rational to evaluate XBP1 as an antigen to develop a potential vaccine based immunotherapy against different types of solid tumors. Methods: XBP1 gene expression was investigated in a variety of primary tumor cells by searching the canEvlove and Oncomine databases and examined its differential expression level from normal cells. A cocktail of heteroclitic XBP1 unspliced (US)184-192 (YISPWILAV) and heteroclitic XBP1 spliced (SP)367-375 (YLFPQLISV) peptides were used to evoke XBP1 specific cytotoxic T Lymphocytes (XBP1-CTL) ex vivo to target breast, colon, and pancreatic cancer cells. XBP1-CTL were also evaluated for critical T cell markers, transcription regulators, and generation of specific memory CTL subsets. Results: Significantly higher XBP1 gene expression was detected in primary tumor cells from breast and colon cancer patients compared to the corresponding normal cells from healthy donors. Using a cocktail of immunogenic heteroclitic XBP1 US and SP peptides with improved HLA-A2 binding/stability as compared to their native counterparts, we induced XBP1-specific CTL from normal HLA-A2+ individuals' CD3+ T cells. The XBP1-CTL displayed an increased frequency of CD3+CD8+ T cells with enhanced expression (% positive cells, mean fluorescence intensity) of surface T cell markers including CD38, CD40L, CD69, 41BB (CD137), ICOS (CD278) and TCRαβ. In addition, the XBP1-CTL were enriched for central memory (CM: CD45RO+CCR7+) and effector memory (EM: CD45RO+CCR7-) CD3+CD8+ T cells as compared to baseline (unstimulated) CD3+CD8+ T cells. Functionally, the memory (CD45RO+) XBP1-CTL subsets showed increased levels of cellular proliferation, IFN-γ production, IL-2 production, and CD107a degranulation in response to HLA-A2+ breast (MB231), colon cancer (LS180) or pancreatic cancer (Panc1) cell lines. Finally, memory (CD45RO+) subset of XBP1-CTL expressed higher levels of Tbet and Eomes transcription regulators as compared to non-memory (CD45RO-) XBP1-CTL, with the highest frequencies of IFN-γ producing Tbet+, Eomes+ or Granzyme B+ cells in the CM subset. Conclusions: These results provide the rational for an immunotherapeutic vaccine comprised of a cocktail of heteroclitic XBP1 US184-192 and XBP1 SP367-375 HLA-A2 peptides to induce XBP1-CTL expressing critical T cell markers and transcription regulators as well as distinct memory CTL subsets with specific anti-tumor activities against breast, colon and pancreatic cancers. Citation Format: Jooeun Bae, Rao Prabhala, Ruben Carrasco, Ann-Hwee Lee, Alec Kimmelman, Kenneth C. Anderson, Nikhil Munshi. Novel heteroclitic XBP1 peptides induce antigen-specific memory CD3+CD8+ T cells expressing critical T cell markers and transcription regulators. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2894. doi:10.1158/1538-7445.AM2014-2894

Cytokine response to selected MTB antigens in Ghanaian TB patients, before and at 2 weeks of anti-TB therapy is characterized by high expression of IFN-γ and Granzyme B and inter- individual variation.

BackgroundThere has been a long held belief that patients with drug-susceptible TB are non-infectious after two weeks of therapy. Recent microbiological and epidemiological evidence has challenged this dogma, however, the nature of the Mtb-specific cellular immune response during this period has not been adequately investigated. This knowledge could be exploited in the development of immunological biomarkers of early treatment response.MethodsCellular response to four Mtb infection phase-dependent antigens, ESAT-6/CFP-10 fusion protein and three DosR encoded proteins (Rv1733c, Rv2029c, Rv2628) were evaluated in a Ghanaian TB cohort (n=20) before and after 2 weeks of anti TB therapy. After 6-days in vitro stimulation, Peripheral blood mononuclear cell (PBMC) culture supernatant was harvested and the concentration of IFN-γ, Granzyme B, IL-10, IL-17, sIL2Rα and TNF-α were determined in a 6-plex Luminex assay. Frequencies of IFN-γ + CD4 and CD8 T cells were also determined in an intracellular cytokine assay.ResultsAll antigens induced higher levels of IFN-γ, followed by Granzyme B, TNF-α and IL-17 and low levels of IL-10 and sIL-2R-α in PBMC before treatment and after 2 weeks of treatment. Median cytokine levels of IFN-γ, Granzyme B, IL-17 and sIL-2R-α increased during week two, but it was significant for only Rv1733-specific production of Granzyme B (P = 0. 013). The median frequency of antigen specific IFN-γ + CD4 T cells increased at week two; however, only the increase in the ESAT-6/CFP-10-specific response was significant (P = 0. 0008). In contrast, the median frequency of ESAT-6/CFP-10- specific IFN-γ + CD8 T cell responses declined during week two (P = 0. 0024). Additionally, wide inter-individual variation with three distinct patterns were observed; increase in all cytokine levels, decrease in all cytokine levels and fluctuating cytokine levels after 2 weeks of treatment.ConclusionThe second week of effective chemotherapy was characterized by a general increase in cytokine response to Mtb-specific antigens suggestive of an improvement in cellular response with therapy. However, the wide inter-individual variation observed would limit the utility of cytokine biomarkers during this period.Electronic supplementary materialThe online version of this article (doi:10.1186/1471-2334-14-495) contains supplementary material, which is available to authorized users.

Abstract 286: Immune Dysfunction in a Vasopressin-Induced Mouse Model of Preeclampsia

Preeclampsia is a disease of pregnancy and the postpartum period, affecting 5-7% of all U.S. pregnancies. We recently determined that elevated secretion of arginine vasopressin (AVP) in humans is detected as early as the 6th week of pregnancy in the women that subsequently develop preeclampsia. Further, we have determined that in C57BL/6 mice, chronic AVP infusion serves as a clinically-relevant and pregnancy-specific model of preeclampsia. Although the pathogenesis of preeclampsia is still poorly understood, an inflammatory immune response is clearly involved. AVP secretion is stimulated by proinflammatory cytokines and AVP in turn can act upon receptors present on lymphocytes. We hypothesize that hypersecretion of AVP results in maternal-fetal immune alterations in preeclamptics. Immune responses were evaluated in wild-type C57BL/6 female mice chronically infused with AVP (24 ng/hr or saline s.c.) throughout pregnancy. We observed an increase in the frequency of IL-12 (saline N=7: 1.1±0.2, vs AVP N=9: 2.2±0.4, P&lt;0.05), IL-17 (saline N=7: 1.2±0.17, vs AVP N=9: 2.6±0.4, P&lt;0.05) and TNFa (saline N=8: 0.9±0.1, vs AVP N=9: 1.6±0.1, P&lt;0.005) expressing lymphocytes isolated from AVP mice. Additionally, the frequency of IFNg expressing lymphocytes was increased in AVP mice, approaching statistical significance (saline N=8: 2.2±0.9, vs AVP N=9: 3.0±0.4, P=0.059). The frequency of IL-6, IL-10, and LAP expressing splenic lymphocytes were similar between saline vs. AVP mice. Interestingly, maternal plasma revealed a significant reduction in IL-17 (saline N=4: 1.0e+7±3.8e+6, vs AVP N=5: 3.1e=5±1.3e+5 ng/g, P&lt;0.05) in AVP mice. Neither IL-4 nor IFNg were detectable in maternal plasma of either group. Additionally, IL-17 trended higher in the amnionic fluid and lower in the placenta of AVP mice. IL-4 production trended lower in both the placenta and amnionic fluid of AVP-infused mice, while IFNg was similar between groups. These data support our hypothesis that AVP hypersecretion results in the maternal-fetal immune alterations associated with the development of preeclampsia. Ongoing experiments are aimed at identifying the lymphocytes and cytokines involved as well as local vs. systemic immune dysfunction associated with AVP-induced preeclampsia.

The effect of aging on the frequency, phenotype and cytokine production of human blood CD4 + CXCR5 + T follicular helper cells: comparison of aged and young subjects.

BackgroundT cell-dependent B-cell responses decline with age, indicating declined cognate helper activity of aged CD4 + T cells for B cells. However, the mechanisms remain unclear. T follicular helper (Tfh) cells, a novel T helper subset, play an essential role in helping B cells differentiation into long-lived plasma cells in germinal center (GC) or short-lived plasma cells. In the present study, we proposed that there might existe changes of proportion, phenotype or cytokine production of blood Tfh cells in healthy elderly individuals compared with healthy young individuals.ResultsThe results showed that frequencies of aged blood CXCR5 + CD4 + Tfh cells increased compared with young subjects. Both aged and young blood CXCR5 + CD4 + Tfh cells constitutively expressed CD45RO, CCR7 and CD28, and few of these cells expressed CD69 or HLA-DR, which indicated that they were resting memory cells. There was no significant difference of IL-21 frequency production by aged blood CXCR5 + CD4 + Tfh determined by FACS compared with young individuals, however, aged PBMCs produced significantly higher levels of IL-21 evaluated by ELISA. Furthermore, there were no significant differences of percentages of IFN-γ, IL-4, IL-17 or IL-22 production by aged Tfh cells compared with their counterparts of young individuals respectively. However, frequencies of IL-17+ cells within aged CD4 + CXCR5-T cells were markedly lower than in the young individuals. Furthermore we observed different frequencies of IFN-γ, IL-17, IL-4 or IL-22 production by Tfh or by CD4 + CXCR5- cells in aged and young subjects respectively.ConclusionsOur data demonstrated that the frequencies of blood memory CXCR5 + CD4 + Tfh cells increased in the elderly population. There were similar frequencies of Th characterized cytokine production such as IL-21, IFN-γ, IL-4, IL-17 or IL-22 in aged and young Tfh cells. However, aged PBMCs produced a significantly higher amount of IL-21 compare to young subjects.

The frequencies of IFNγ+IL2+TNFα+ PPD-specific CD4+CD45RO+ T-cells correlate with the magnitude of the QuantiFERON® gold in-tube response in a prospective study of healthy indian adolescents.

BackgroundQuantiFERON-TB Gold In-Tube (QFT) is an IFNγ-release assay used in the diagnosis of Mycobacterium tuberculosis (MTB) infection. The risk of TB progression increases with the magnitude of the MTB-specific IFNγ-response. QFT reversion, also associated with low Tuberculin Skin Test responses, may therefore represent a transient immune response with control of M. tuberculosis infection. However, studies at the single cell level have suggested that the quality (polyfunctionality) of the T-cell response is more important than the quantity of cytokines produced.ObjectiveTo explore the quality and/or magnitude of mycobacteria-specific T-cell responses associated with QFT reversion and persistent QFT-positivity.MethodsMulti-color flowcytometry on prospectively collected peripheral blood mononuclear cells was applied to assess mycobacteria-specific T-cell responses in 42 QFT positive Indian adolescents of whom 21 became QFT negative (reverters) within one year. Ten QFT consistent negatives were also included as controls.ResultsThere was no difference in the qualitative PPD-specific CD4+ T-cell response between QFT consistent positives and reverters. However, compared with QFT consistent positives, reverters displayed lower absolute frequencies of polyfunctional (IFNγ+IL2+TNFα+) CD4+ T-cells at baseline, which were further reduced to the point where they were not different to QFT negative controls one year later. Moreover, absolute frequencies of these cells correlated well with the magnitude of the QFT-response.ConclusionWhereas specific polyfunctional CD4+ T-cells have been suggested to protect against TB progression, our data do not support that higher relative or absolute frequencies of PPD-specific polyfunctional CD4+ T-cells in peripheral blood can explain the reduced risk of TB progression observed in QFT reverters. On the contrary, absolute frequencies of these cells correlated with the QFT-response, suggesting that this readout reflects antigenic load.

AB0129 CD45RA−Foxp3low Non-Regulatory T Cells Are Increased in Synovial Fluid from Patients with Rheumatoid Arthritis

BackgroundHuman CD4+ T cells can be classified as either naïve, CCR7+CD45RA− central memory (TCM), or CCR7−CD45RA− effector memory (TEM) cells. In addition to CD45RA and CCR7, CD27 and CD28 have...

Therapeutic vaccination against shingles broadens the VZV-specific CD4+ T cell response (VAC7P.994)

Abstract Life-long latent neuronal infection with varicella zoster virus (VZV) is a legacy of childhood chickenpox. VZV reactivation occurs in about 1/3 of persons to cause shingles. Live, attenuated VZV (vOka)—the only licensed therapeutic vaccine—moderately reduces both the incidence and the severity of shingles. The partial level of protection is poorly understood but may plausibly derive from variation in T cell boosting. Twelve subjects (&amp;gt;50 years old) were vaccinated with vOka and blood obtained on days 0, 14, and 28. Ex vivo ICC analyses confirmed boosting of vOka-reactive T cells: the mean increase in frequency of IFNγ+IL2+ CD4+ T cells was 74% by day 14 (p=0.02). We enriched and expanded VZV-specific CD4+ T cells in an unbiased manner and defined the specificity and breadth of the resulting polyclonal CD4+ T cell lines using each of the 70 known VZV proteins. Prior to boosting, the median number of detectable responses was 9 ORFs (range 3-10). Vaccination increased the median breadth to 17 ORFs (range 9-20) at day 28. Prevalent targets before and after boosting were glycoproteins gE, gI, and gH, and the tegument proteins encoded by ORF12 and ORF44. While new responses were noted post-vaccination, baseline responses rarely disappeared. T cell breadth was well-maintained during VZV latency and further increased by therapeutic vaccination. In addition to CD4+ T cell magnitude, specificity and breadth are now accessible as candidate immune correlates of vaccine efficacy.

Increased Notch pathway activation in Behçet’s disease

Behçet's disease (BD) is a refractory inflammatory disorder with unknown causes. Since the Notch pathway is critically involved in the immune response, the present study was undertaken to investigate the role of this pathway in BD. Hes-1, Notch 1-4, Jagged-1, DLL-1 and DLL-4 expression, frequency of IFN-γ and IL-17 expressing Th cells, Notch intracellular domain (NICD), phosphorylation of signal transducer and activator of transcription 3 (STAT3) and the production of IFN-γ and IL-17 were examined by real-time PCR, flow cytometry and ELISA. Notch blockade was performed using the γ-secretase inhibitor N-[N-(3,5-difluorophenacetyl)-1-alanyl]-S-phenylglycine t-butyl ester (DAPT). Transfection with miR-23b mimics and inhibitor was used to examine the effect of miR-23b on Notch pathway activation. Active BD patients showed an increased activation of the Notch pathway in association with a higher Th17 response. Notch blockade preferentially inhibited Th17 responses. The effect of Notch blockade on the Th17 response was associated with a lower level of STAT3 phosphorylation. miR-23b was significantly decreased in CD4(+) T cells from active BD patients. CD4(+) T cells transfected with miR-23b showed a reduced expression of NICD and a reduced frequency of IL-17- and IFN-γ-expressing T cells. The present study suggests that an increased activation of the Notch pathway may contribute to the pathogenesis of BD. Decreased expression of miR-23b may be involved in activation of the Notch pathway in BD. Manipulation of the Notch pathway may offer a novel therapeutic approach for BD.

Regulatory B cells in ANCA-associated vasculitis

ObjectivesB cells have immunoregulatory function acting as antigen-presenting cells. A separate subset of interleukin (IL)-10 producing B cells (Breg) regulating T cell mediated immunity has been identified. In the present...

Antigen-specific natural killer cell cytokine production in chronic hepatitis C infection (P6062)

Abstract Chronic hepatitis C virus (HCV) infection results in an inflammatory liver disease leading to fibrosis and cirrhosis. The progression of liver disease is thought to be immune-mediated because HCV itself is non-cytopathic. Given that HCV-specific T cells are diminished in number and functionally exhausted in chronic HCV infection, it remains unclear which cell population drives disease pathogenesis. Here, we investigated the function of natural killer (NK) cells, the major innate immune cell population in the liver. PBMCs from 15 patients with chronic HCV infection were stimulated for 8 hours in a whole blood activation assay with pools of overlapping 18-mer peptides comprising HCV structural (E1, E2) and nonstructural (NS3) proteins. Cytokine production by NK cells and T cells was assessed by multicolor flow cytometry. The frequency of IFN-γ+ NK cells was 5-10 fold greater than the frequency of IFN-γ+ T cells. A minority of IFN-γ+ NK cells co-produced TNF-α. NK cell responses to HCV peptides varied between subjects, but did not correlate with T cell responses or viremia. This study demonstrates that NK cells are activated in an antigen-specific manner in chronic HCV infection and respond to both structural and nonstructural HCV proteins. The mechanism of antigen-specific NK cell activation is currently under investigation.

Abstract 1237: Mechanism of action of L-BLP25 in preclinical pancreatic tumor models.

Abstract Background. L-BLP25 is an investigational antigen-specific cancer immunotherapeutic agent targeting human mucin 1 (MUC1). A single low dose of cyclophosphamide (CPA) is known to be immunostimulatory and may enhance the anti-tumor effects of L-BLP25 when given 3 days before treatment initiation. Here we report the immune and anti-tumor efficacy of L-BLP25 with CPA pretreatment in subcutaneous (s.c.) and orthotopic models of murine pancreatic cancer. These models allow for reproduction of the clinical scenario, where 8 weekly doses of L-BLP25 are administered. Methods. Murine pancreatic tumor cells Panc02 transfected with human MUC1 were injected for comparison s.c. or orthotopically into human MUC1 transgenic mice. Mice received either vehicle control (PBS), CPA (100 mg/kg), L-BLP25 (100 μg), or L-BLP25 (100 μg) + CPA (100 mg/kg). CPA was administered intravenously (i.v.) 3 days prior to initiation of 8 weekly intradermal (i.d.) or s.c. L-BLP25 injections. Tumor volume was monitored and splenic cell populations were quantified by FACS. In the s.c. tumor model, the contribution of CD4+ and CD8+ T cell subsets to the inhibition of tumor growth was studied. In the orthotopic model, antigen-specific IFN-γ secretion was assessed via ex vivo T cell re-stimulation with antigen alone. Results. In the s.c. model of pancreatic cancer, tumor volume was reduced compared to vehicle at day 49 after i.d. administration of L-BLP25 (41.4%, p&amp;lt;0.02) and L-BLP25 + CPA (55.5%, p&amp;lt;0.02). In multiple studies, tumor volume was consistently lower in mice treated with L-BLP25 + CPA vs. L-BLP25 alone. L-BLP25 + CPA s.c. treatment was effective at day 49 with 44% greater inhibition of tumor growth and more pronounced extended survival compared to i.d. treatment, supporting the route of administration in the clinic. Various splenic immune cell populations were increased by s.c. L-BLP25 + CPA treatment compared to vehicle and L-BLP25 alone, including the CD8+ effector memory/Treg ratio. Mice treated with s.c. L-BLP25 + CPA after CD8+ T cell depletion had a greater tumor volume compared to T cell-sufficient mice, while CD4+ T cell depletion had no effect. In the orthotopic model of pancreatic cancer, median survival was improved with s.c. L-BLP25 + CPA treatment vs. vehicle (p&amp;lt;0.05) and vs. L-BLP25 alone (non-significant). When stimulated ex vivo with the BP25 peptide, the frequency of IFN-γ producing CD4+ T cells isolated from the spleens of mice treated with L-BLP25 + CPA was significantly higher than in all other treatment groups (p&amp;lt;0.001). CD8+ T cells were found to produce no IFN-γ after in vitro re-stimulation. Conclusions. When administered after a single, low-dose pre-treatment of CPA, L-BLP25 immunotherapy exhibits anti-tumor activity, immune activation and prolonged survival in murine pancreatic cancer models. T cell depletion data indicate a CD8+ T cell-mediated anti-tumor response, whilst IFN-γ production by CD4+ helper T cells may contribute to prolonged survival. Citation Format: Kenneth Hance, Bo Marelli, Jin Qi, Guozhong Qin, Huakui Yu, Hong Wang, Xiaomei Xu, Robert Tighe, Beatrice Brunkhorst, Yan Lan, Robert Hofmeister, Helen Sabzevari, Michael Wolf. Mechanism of action of L-BLP25 in preclinical pancreatic tumor models. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1237. doi:10.1158/1538-7445.AM2013-1237

Impact of oral silymarin on virus‐ and non‐virus‐specific T‐cell responses in chronic hepatitis C infection

Silymarin displays anti-inflammatory effects on T lymphocytes in vitro. The immunomodulatory properties of oral silymarin in vivo in humans with chronic hepatitis C have not previously been characterized. We hypothesized that silymarin would suppress T-cell proliferation and pro-inflammatory cytokine production of virus- and non-virus-specific T cells while increasing anti-inflammatory IL-10 production in vivo. Patients from one site of the SyNCH-HCV double-masked, placebo-controlled study of oral silymarin in prior interferon nonresponders with chronic hepatitis C provided blood samples at baseline and treatment week 20. Mononuclear cells were stimulated with recombinant HCV proteins and controls in (3) H-thymidine proliferation assays, IFNγ ELISPOT and IL-10 ELISPOT. The frequency of CD4(+) CD25(hi) and CD4(+) foxp3(+) regulatory T cells, serum cytokine levels, serum IP-10 and lymphocyte interferon-stimulated gene expression were also quantified at baseline and week 20. Thirty-two patients were recruited (10; placebo, 11; 420mg three times a day, 11; 700mg three times a day). Serum ALT and HCV RNA titres did not change in any group. HCV-specific CD4(+) T-cell proliferation and the frequency of IFNγ- and IL-10-producing T cells were not significantly changed in silymarin-treated subjects. However, C.albicans-induced T-cell IFNγ and phytohaemagglutinin-induced T-cell proliferation were suppressed by silymarin therapy. A trend towards augmentation of interferon-induced ISG15 expression was present in the high-dose silymarin group. While no effect on HCV-specific T cells was identified, these data confirm that high-dose oral silymarin exerts modest nonspecific immunomodulatory effects in vivo. The impact of this anti-inflammatory effect on long-term liver health in chronic hepatitis C merits future clinical investigation.

Comparative Analysis of the Magnitude, Quality, Phenotype, and Protective Capacity of Simian Immunodeficiency Virus Gag-Specific CD8+ T Cells following Human-, Simian-, and Chimpanzee-Derived Recombinant Adenoviral Vector Immunization

Recombinant adenoviral vectors (rAds) are the most potent recombinant vaccines for eliciting CD8(+) T cell-mediated immunity in humans; however, prior exposure from natural adenoviral infection can decrease such responses. In this study we show low seroreactivity in humans against simian- (sAd11, sAd16) or chimpanzee-derived (chAd3, chAd63) compared with human-derived (rAd5, rAd28, rAd35) vectors across multiple geographic regions. We then compared the magnitude, quality, phenotype, and protective capacity of CD8(+) T cell responses in mice vaccinated with rAds encoding SIV Gag. Using a dose range (1 × 10(7)-10(9) particle units), we defined a hierarchy among rAd vectors based on the magnitude and protective capacity of CD8(+) T cell responses, from most to least, as: rAd5 and chAd3, rAd28 and sAd11, chAd63, sAd16, and rAd35. Selection of rAd vector or dose could modulate the proportion and/or frequency of IFN-γ(+)TNF-α(+)IL-2(+) and KLRG1(+)CD127(-)CD8(+) T cells, but strikingly ∼30-80% of memory CD8(+) T cells coexpressed CD127 and KLRG1. To further optimize CD8(+) T cell responses, we assessed rAds as part of prime-boost regimens. Mice primed with rAds and boosted with NYVAC generated Gag-specific responses that approached ∼60% of total CD8(+) T cells at peak. Alternatively, priming with DNA or rAd28 and boosting with rAd5 or chAd3 induced robust and equivalent CD8(+) T cell responses compared with prime or boost alone. Collectively, these data provide the immunologic basis for using specific rAd vectors alone or as part of prime-boost regimens to induce CD8(+) T cells for rapid effector function or robust long-term memory, respectively.