Significant Increase In IFN-γ Production Research Articles

Selective APC-targeting of a novel Fc-fusion multi-immunodominant recombinant protein (tTax-tEnv:mFcγ2a) for HTLV-1 vaccine development

AimsHTLV-1 causes two life-threatening diseases: adult T-cell leukaemia/lymphoma and HTLV-1-associated myelopathy/tropical spastic paraparesis. Due to the lack of proper treatment, an effective HTLV-1 vaccine is urgently needed. Main methodsDNA sequences of 11–19 and 178–186 amino acids of HTLV-1-Tax and SP2 and P21 were fused to the mouse-Fcγ2a, or His-tag called tTax-tEnv:mFcγ2a and tTax-tEnv:His, respectively. These constructs were produced in Pichia pastoris, and their immunogenicity and protective properties were assessed in a mouse challenging model with an HTLV-1-MT2 cell line. Key findingsThe immunogenicity assessments showed significant increase in IFN-γ production in animals receiving tTax-tEnv:mFcγ2a (1537.2 ± 292.83 pg/mL) compared to tTax-tEnv:His (120.28 ± 23.9, p = 0.02). IL-12 production also increased in group receiving tTax-tEnv:mFcγ2a than tTax-tEnv:His group, (23 ± 2.6 vs 1.5 ± 0.6, p = 0.01), respectively. The IFN-γ and IL-12 levels in the Fc-immunised group were negatively correlated with PVL (R = -0.82, p < 0.04) and (R = -0.87, p = 0.05), respectively. While, IL-4 was increased by tTax-tEnv:His (21.16 ± 1.76 pg/mL) compared to tTax-tEnv:mFcγ2a (13.7 ± 1.49, p = 0.019) with a negative significant correlation to PVL (R = -0.95, p = 0.001). SignificanceThe mouse challenging assay with tTax-tEnv:mFcγ2a showed 50 % complete protection and a 50 % low level of HTLV-1-PVL compared to the positive control receiving HTLV-1-MT2 (p = 0.001). Challenging experiments for the His-tag protein showed the same outcome (p = 0.002) but by different mechanisms. The Fc-fusion construct induced more robust Th1, and His-tag protein shifted more to Th2 immune responses. Therefore, inducing both T helper responses, but a Th1/Th2 balance in favour of Th1 might be necessary for appropriate protection against HTLV-1 infection, spreading via cell-to-cell contact manner.

Association between interferon-gamma (IFN-γ) gene polymorphisms (+874A/T and +2109A/G), and susceptibility to hepatitis B viral infection (HBV)

Interferon-gamma (IFN-γ) is a chief proinflammatory cytokine with a significant role in the immune response against viral infections. Today there is increasing evidence about the association between individual genetic polymorphisms and cytokines in predicting HBV infection susceptibility. This study aimed to investigate the association between IFN-γ gene polymorphisms and susceptibility to hepatitis B viral infection (HBV), and the impact of these genetic polymorphisms on IFN-γ production. IFN-γ (+874A/T, rs2430561, and +2109A/G, rs1861494) was genotyped by single-stranded polymorphism-polymerase chain reaction (SSP-PCR) in 126 Egyptians with chronic HBV infection and in 100 healthy control subjects. The plasma levels of IFN-γ were measured by Enzyme-linked immunosorbent assay (ELISA). Compared to the control subjects there was a slight increase in +874TT genotype frequency in HBV patients. However, no statistical significance in IFN-γ (+874A/T and +2109A/G) genotype/allele distribution was demonstrated, indicating the lack of association between these SNPs and susceptibility to HBV infection. In +2109A/G, only AG genotype was observed with a complete abrogation of GG and AA genotypes. Haplotypes between different loci on selected genes showed insignificant changes in their frequency in patients and control subjects. HBV patients had a significantly higher level of IFN-γ (P < 0.001) compared to controls. The maximum significant increase in IFN-γ production was observed in subjects harboring the +874TA genotype. As no association could be characterized between the polymorphism in IFN-γ (+874A/T and +2109A/G) and susceptibility to chronic HBV infection, our data support the concept that IFN-γ gene polymorphisms are not predictors of HBV susceptibility in this segment of the Egyptian population.

Modulation of the human immune status by spinal thermal massage: a non-randomized controlled study

Thermal and massage therapies have long been used to control pain. Although spinal thermal massage (STM) has been used worldwide, its effectiveness has not been proven in a controlled clinical study. We here conducted a non-randomized controlled trial to assess the pain-relieving and immunomodulatory effects of STM in old-aged patients experiencing pain or disability. The experimental group was treated with STM five times a week for 8 weeks and rehabilitative regular care (RRC). The control group was treated with only RRC. Pain and immunological parameters were tested before treatment and after 4 and 8 weeks of treatment. The scores of three pain parameters were lowered by STM, and the differences between the groups were statistically significant at the two time points (p &lt; 0.01). Quality of life determined using the 3-level EuroQol five-dimensional questionnaire scores was significantly higher in patients in the experimental group than those in the control group. Effect sizes (ES) were in the range of medium to large in the pain-related measures (0.54–1.22). The total leukocyte counts and the proportions of lymphocytes and subsets were not significantly different between the groups, whereas the proportions of monocytes and natural killer (NK) cells were higher in the experimental group than in the control group after 8 weeks (p &lt; 0.05). The production of interleukin (IL)-4 and interferon γ in T cells was not significantly different between the groups, whereas the production of IL-2 was high in the control group. However, there was a significant increase in IFN-γ production by NK cells in the experimental group (at 4 weeks, p &lt; 0.05). ES were medium in the immunological measures (0.53–0.68). No significant difference was observed in the production of proinflammatory cytokines, IL-1β, tumor necrosis factor α, or IL-6 between the groups. In conclusion, STM treatment has a positive effect on subjective pain and quality of life. It also enhanced NK cell proportion and activity, suggesting that STM may be beneficial in the prevention of viral diseases and cancer in old-aged people.

Dual oxidase 1 limits the IFNγ-associated antitumor effect of macrophages.

BackgroundMacrophages play pivotal roles in tumor progression and the response to anticancer therapies, including radiotherapy (RT). Dual oxidase (DUOX) 1 is a transmembrane enzyme that plays a critical role in oxidant generation.MethodsSince we found DUOX1 expression in macrophages from human lung samples exposed to ionizing radiation, we aimed to assess the involvement of DUOX1 in macrophage activation and the role of these macrophages in tumor development.ResultsUsing Duox1−/− mice, we demonstrated that the lack of DUOX1 in proinflammatory macrophages improved the antitumor effect of these cells. Furthermore, intratumoral injection of Duox1−/− proinflammatory macrophages significantly enhanced the antitumor effect of RT. Mechanistically, DUOX1 deficiency increased the production of proinflammatory cytokines (IFNγ, CXCL9, CCL3 and TNFα) by activated macrophages in vitro and the expression of major histocompatibility complex class II in the membranes of macrophages. We also demonstrated that DUOX1 was involved in the phagocytotic function of macrophages in vitro and in vivo. The antitumor effect of Duox1−/− macrophages was associated with a significant increase in IFNγ production by both lymphoid and myeloid immune cells.ConclusionsOur data indicate that DUOX1 is a new target for macrophage reprogramming and suggest that DUOX1 inhibition in macrophages combined with RT is a new therapeutic strategy for the management of cancers.

Safety and immunogenicity of a mosquito saliva peptide-based vaccine: a randomised, placebo-controlled, double-blind, phase 1 trial

In animal models, immunity to mosquito salivary proteins protects animals against mosquito-borne disease. These findings provide a rationale to vaccinate against mosquito saliva instead of the pathogen itself. To our knowledge, no vector salivary protein-based vaccine has been tested for safety and immunogenicity in humans. We aimed to assess the safety and immunogenicity of Anopheles gambiae saliva vaccine (AGS-v), a peptide-based vaccine derived from four A gambiae salivary proteins, in humans. In this randomised, placebo-controlled, double-blind, phase 1 trial, participants were enrolled at the National Institutes of Health Clinical Center in Bethesda, MD, USA. Participants were eligible if they were healthy adults, aged 18-50 years with no history of severe allergic reactions to mosquito bites. Participants were randomly assigned (1:1:1), using block randomisation and a computer-generated randomisation sequence, to treatment with either 200 nmol of AGS-v vaccine alone, 200 nmol of AGS-v with adjuvant (Montanide ISA 51), or sterile water as placebo. Participants and clinicians were masked to treatment assignment. Participants were given a subcutaneous injection of their allocated treatment at day 0 and day 21, followed by exposure to feeding by an uninfected Aedes aegypti mosquito at day 42 to assess subsequent risk to mosquito bites in a controlled setting. The primary endpoints were safety and immunogenicity at day 42 after the first immunisation. Participants who were given at least one dose of assigned treatment were assessed for the primary endpoints and analysis was by intention to treat. The trial was registered with ClinicalTrials.gov, NCT03055000, and is closed for accrual. Between Feb 15 and Sept 10, 2017, we enrolled and randomly assigned 49 healthy adult participants to the adjuvanted vaccine (n=17), vaccine alone (n=16), or placebo group (n=16). Five participants did not complete the two-injection regimen with mosquito feeding at day 42, but were included in the safety analyses. No systemic safety concerns were identified; however, one participant in the adjuvanted vaccine group developed a grade 3 erythematous rash at the injection site. Pain, swelling, erythema, and itching were the most commonly reported local symptoms and were significantly increased in the adjuvanted vaccine group compared with both other treatment groups (nine [53%] of 17 participants in the adjuvanted vaccine group, two [13%] of 16 in the vaccine only group, and one [6%] of 16 in the placebo group; p=0·004). By day 42, participants who were given the adjuvanted vaccine had a significant increase in vaccine-specific total IgG antibodies compared with at baseline than did participants who were give vaccine only (absolute difference of log10-fold change of 0·64 [95% CI 0·39 to 0·89]; p=0·0002) and who were given placebo (0·62 [0·34 to 0·91]; p=0·0001). We saw a significant increase in IFN-γ production by peripheral blood mononuclear cells at day 42 in the adjuvanted vaccine group compared with in the placebo group (absolute difference of log10 ratio of vaccine peptide-stimulated vs negative control 0·17 [95% CI 0·061 to 0·27]; p=0·009) but we saw no difference between the IFN-γ production in the vaccine only group compared with the placebo group (0·022 [-0·072 to 0·116]; p=0·63). AGS-v was well tolerated, and, when adjuvanted, immunogenic. These findings suggest that vector-targeted vaccine administration in humans is safe and could be a viable option for the increasing burden of vector-borne disease. Office of the Director and the Division of Intramural Research at the National Institute of Allergy and Infectious Diseases, and National Institutes of Health.

Abstract B044: Development of a highly potent humanized antibody against CD178: A novel therapeutic target in immuno-oncology

Abstract CD178 (FASLG) is an emerging therapeutic target in immuno-oncology (IO) since CD178/CD95-dependent signalling plays several crucial roles in regulating the immune response to tumours including T cell persistence/survival, T cell exclusion and tumour-dependent T cell killing. Using the mouse hybridoma approach antibodies were raised against the extracellular domain (Pro134-Leu281) of recombinant human CD178. Clone 2B11 was selected for humanisation based on its excellent potency and lack of problem residues in the CDR. Following humanisation by CDR grafting and the introduction of additional mutations to improve affinity and biophysical properties, FBP002 was selected as a potential therapeutic candidate. FB-002 is an IgG4 (S228P) isotype antibody that binds CD178 with high potency in in vitro ELISA assays (IC50 161 pM; 24 ng/mL) and in Surface Plasmon Resonance (SPR) studies (KD of 97 pM). In cellular assays, FBP002 inhibits cell death induced by CD178 in both Jurkat A3 cells (IC50 2.1 ng/mL) and in unstimulated CD4+ human donor T cells (IC50 37 ng/mL). In a model of activation-induced cell death, FBP002 inhibited anti-CD3/anti-CD28 induced cytotoxicity in Jurkat A3 cells (IC50 418 ng/mL). Repeated stimulation of effector T cells can severely limit their function and blunt their anti-tumour response. To investigate the role of CD178 in sustaining T cell activation, we employed a T cell re-stimulation assay by treating human PBMCs with staphylococcal enterotoxin B (SEB) super-antigen for 5 days to activate T cells, followed by IL2 incubation for 14 days, and then a secondary treatment with SEB for 5/6 days. FBP002 significantly (p&amp;lt;0.05) increased cell proliferation following secondary SEB treatment and was also associated with a significant increase in IFNγ production measured by ELISA (p&amp;lt;0.05). FBP002 was more effective than either anti-PD-1 or anti-PD-L1 in this re-stimulation assay and enhanced both PD-1 and PD-L1 activity suggesting a non-overlapping role for CD178 in maintaining the function of activated T cells. To investigate in vivo effects, subcutaneous MC38 murine colon tumours were established in syngeneic immune competent female C57BL/6 mice. Once tumours reached 100 mm3, mice were treated with a surrogate anti-murine CD178 antibody (10 mg/kg i.p. twice weekly), or an isotype control. Anti-CD178 antibody treatment was well tolerated (no body weight loss) and significantly delayed MC38 tumour growth (p&amp;lt;0.05). Immunohistchemistry and image analysis demonstrated that the anti-tumour effect was associated with an increased CD8/Treg ratio in the tumour suggesting that inhibiting CD178 signalling disproportionately protects effector T cells from apoptosis leading to a more effective immune response. In conclusion, we have developed FBP002, a highly potent humanised anti-CD178 antibody that we anticipate will have broad therapeutic potential in the immunological treatment of tumours both as a monotherapy and in combination with established IO agents due to its ability to simultaneously affect multiple aspects of tumour resistance to T cell therapies. Citation Format: Georgia Cerillo, Anderson J Ryan, Peter D Davis. Development of a highly potent humanized antibody against CD178: A novel therapeutic target in immuno-oncology [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr B044. doi:10.1158/1535-7163.TARG-19-B044

The Role of O-Antigen in LPS-Induced Activation of Human NK Cells.

NK cells can be stimulated by bacterial lipopolysaccharides (LPS). Unlike macrophages, human NK cells do not express or express very low level of surface TLR4 receptor normally required for the LPS stimulation. This has led to the assumption that the mechanisms of stimulating action of LPS on macrophages and NK cells differs. In this work, we investigated the effects of different forms of E. coli LPS, including mutants lacking O-antigen structures, and deacylated LPS on IFNγ production by purified human NK cells. The main findings were the following: (1) NK cells were more sensitive to the S-forms of LPS than the R-forms (LPS lacking O-antigen); (2) LPS triggered a significant increase in IFNγ production by NK cells in concentrations about 1000 times higher than those that can induce cytokine production by macrophages; (3) the composition and structure of saccharide part of LPS have a strong influence on its observed effects on NK cells; and (4) LPS fully retained the ability to trigger cytokine production in NK cells in serum-free media. The acquired data demonstrated that the presence and structure of O-antigen affects the LPS-induced activation of human NK cells.

The effects of OLL1073R-1 yogurt intake on influenza incidence and immunological markers among women healthcare workers: a randomized controlled trial.

Probiotics have been expected to enhance human immune function. The aim of this study was to evaluate the effects of dietary intake of yogurt fermented with Lactobacillus delbrueckii ssp. bulgaricus OLL1073R-1 (OLL1073R-1) on the prevention of influenza during winter and on the activation of immunological markers among women healthcare workers. 961 women aged 20-71 years were randomly assigned to either the yogurt group (n = 479) or the control group (n = 482). Participants in the yogurt group consumed a 112 mL yogurt drink fermented with OLL1073R-1 every day for 16 weeks, whereas those in the control group consumed no yogurt during this period. All participants were instructed not to consume any other kinds of yogurt or fermented dairy products throughout this trial. The cumulative incidence rate of influenza was measured, and immunological markers were examined at the baseline and after 16 weeks. No significant difference in the incidence rate of influenza was found between the two groups (cumulative incidence rates of flu: yogurt 7.5% and control 7.7%). Natural killer (NK) cell activity did not show a significant intervention effect (p = 0.11), whereas the intervention effect on serum interferon gamma (IFN-γ) production was significant (p = 0.03). Other immunological markers did not show significant intervention effects. Consumption of OLL1073R-1 yogurt did not show a significant preventive effect against influenza or a significant enhancement in NK cell activity. However, intake of this yogurt showed an increase in IFN-γ production.

Inhibiting HLA-G restores IFN-γ and TNF-α producing T cell in pleural Tuberculosis

Human Leukocyte Antigen-G (HLA-G), a non-classical, class Ib molecule, has been shown to mediate immunoregulatory functions by inducing apoptosis, inhibits cytotoxicity and differentiation by modulating cytokine secretion. Due to its immune-suppressive function, it facilitates tolerance in feto-maternal interface and transplantation. In contrary, it favours immune evasion of microbes and tumors by inhibiting immune and inflammatory responses. In Tuberculosis (TB), we previously reported differential expression of HLA-G and its receptor Ig-like transcript −2 (ILT-2) in disseminated vs. localized Tuberculosis. The present study explores the impact of HLA-G inhibition on the function of T cells and monocytes, in TB Pleural Effusion (PE), a localized form of TB. Blocking of HLA-G resulted in significant increase in IFN-γ and TNF-α production by CD3+ T cells. Additionally, we observed that HLA-G influences the apoptosis and cytotoxic effect of T cells from TB- PE patients. Next, we checked the impact of interaction between HLA-G and ILT-4 receptor in monocytes derived from TB-PE patients upon blocking and observed significant increase in IFN-γ production. The present study reveals for the first time HLA-G mediated suppression of Th1 cytokines, especially, IFN-γ and TNF-α in TB-PE patients.

Quantification and phenotypic characterisation of peripheral IFN-γ producing leucocytes in chickens vaccinated against Newcastle disease

The aim of this study was to optimise and evaluate an intracellular cytokine staining (ICS) assay for assessment of T cell IFN-γ responses in chickens vaccinated against Newcastle disease (ND). We aimed to validate currently available antibodies to chicken IFN-γ using transfected CHO cells. Moreover, this ICS assay was evaluated for use to detect mitogen and antigen induced IFN-γ production in chicken peripheral blood leucocytes.Chickens from an inbred white leghorn line containing two MHC haplotypes, B19 and B21, were divided into three experimental groups; one group was kept as naive controls, one group was vaccinated intramuscularly twice with a commercial inactivated ND virus (NDV) vaccine, and the last group was vaccinated orally twice with a commercial live attenuated NDV vaccine. PBMC were ex vivo stimulated with ConA or with NDV antigen. The ICS assay was used to determine the phenotype and frequency of IFN-γ positive cells. ConA stimulation induced extensive IFN-γ production in both CD3+TCRγδ+ (γδ T cells) cells and CD3+TCRγδ− cells (αβ T cells), but no significant differences were observed between the experimental groups. Furthermore, a large proportion of the IFN-γ producing cells were CD3− indicating that other cells than classic T cells, secreted this cytokine. NDV antigen stimulation induced IFN-γ production but to a lower extent than ConA and with a large variation between individuals. The CD3+TCR1γδ−CD8α+ (CTL) population produced the highest NDV specific IFN-γ responses, with significantly elevated levels of IFN-γ producing cells in the B19 chickens vaccinated orally with live attenuated NDV vaccine. This was not the case in the B21 animals, indicating a haplotype restricted variation. In contrast, the CD3+TCR1γδ−CD4+ (Th) population did not show a significant increase in IFN-γ production in NDV stimulated samples which was in part due to a high number of IFN-γ producing cells after incubation with medium alone. In conclusion, an ICS assay for phenotyping of IFN-γ producing chicken leukocytes was set up that proved useful in identifying cytokine producing cells upon either mitogen or antigen-specific stimulation.

PD-1/PD-L1 Blocking Enhances CD33/CD3-Bispecific BiTE® Antibody (AMG 330) Mediated Lysis of Primary AML Cells

Antibody-based immunotherapy represents a promising strategy to target and eliminate chemoresistant leukemic cells in acute myeloid leukemia (AML). In our previous work, the potency of the CD33/CD3-bispecific BiTE® antibody AMG 330 to activate and redirect T-cells to AML cells was evaluated in a long-term culture system using unmanipulated peripheral blood (PB) or bone marrow (BM) samples from AML patients. We were able to show effective elimination of AML cells by AMG 330-activated and -expanded residual autologous T-cells (n=13, Krupka et. al, Blood 2014 123(3):356-65). The goal of the present study was to identify and manipulate factors that interfere with AMG 330-mediated lysis of primary AML cells.In our ex-vivo long-term culture system (n= 32 primary diagnosis, 3 relapse), we observed that successful elimination of primary AML cells was predominantly influenced by the initial effector:target (E:T) ratio. Reduced short-term lysis efficacy was observed for patient samples with low E:T ratios (median lysis: E:T ratio <1:10 23.5% vs >1:10 99.3%) after 4 days of culture. However, after 12 days of culture this effect was less prominent as effector T-cell numbers increased and lysis was observed even in cultures with very low initial E:T ratios (up to an E:T ratio of 1:80).Considering the ubiquitous expression pattern of CD33 within the myeloid compartment, the number of AMG 330 treatment days will be limited due to expected hematotoxicity. Therefore, AMG 330 efficacy might benefit by increasing the E:T ratio within a short time period. Programmed cell death-1 (PD-1) and its primary ligand PD-L1 are immune checkpoints that limit T-cell responses and may contribute to slower lysis kinetics during AMG 330 treatment. Therefore, we assessed PD-1 expression on T-cells and PD-L1 expression on primary AML cells. No constitutive expression of PD-1/PD-L1 on T-cells and corresponding AML cells was found at primary diagnosis (PD-1: n=23; PD-L1: n=193). Upon the addition of AMG 330 to our primary ex-vivo AML cultures, we observed a strong upregulation of PD-1 on activated T-cells, which correlated with the extent of T-cell proliferation (10/10). This was most prominent within the subpopulation of CD4+/CD45RA-/CCR7- effector memory T-cells. Furthermore, in response to AMG 330-mediated T-cell activation, we observed an upregulation of PD-L1 on primary AML cells (16/19). Data obtained from AML cell lines confirmed an upregulation of PD-L1 after co-cultivation with T-cells and AMG 330. This phenomenon was cytokine-mediated as the addition of IFNγ and TNFα also induced PD-L1 expression (n=6). Interestingly, we also observed a PD-L1 upregulation on T-cells upon activation with AMG 330, but to a much lower extent compared to primary AML cells (n=17; mean MFI ratio: T-cells: 4.7; AML cells: 12.1). Blockade of the PD-1/PD-L1 interaction through the addition of an inhibitory antibody induced an increase in T-cell proliferation in ex-vivocultures resulting in enhanced cytotoxicity against primary AML cells (lysis on day 18: with/without PD-1 blocking antibody: 75 vs 44%; fold change T-cell expansion: 6 vs 3). This was accompanied by a significant increase in IFNγ production (with/without PD-1 blocking antibody: 280 pg/ml vs 81 pg/ml). Complimentary experiments using primary AML cells and allogeneic T-cells at defined E:T ratios demonstrated that this effect is most prominent in co-cultures with a low percentage of T-cells within the primary sample (lysis on day 7 with/without PD-L1 blocking antibody: E:T ratio 1:1: 100% vs 94.5%; E:T ratio 1:5: 96.6% vs 82.7%; fold change T-cell expansion: E:T ratio 1:1: 3.1 vs 3.1; E:T ratio 1:5: 23.4 vs 9.8). Intriguingly, upon addition of lenalidomide to our primary AML cultures, we were also able to circumvent the immune inhibitory effect of the PD-1/PD-L1 interaction by a decrease in PD-L1 upregulation on primary AML cells.Our data show that AMG 330-mediated lysis of primary AML cells can be enhanced by inhibiting the PD-1/PD-L1 axis on T-cells and corresponding AML cells. The modulation of the PD-1/PD-L1 axis increased T-cell proliferation and accelerated attaining a beneficial E:T ratio. We hypothesize that PD-L1 upregulation on primary AML cells is a relevant immune escape mechanism employed by AML cells to escape cytokine-mediated immune responses. Prospective clinical trials will be needed to assess the relevance of our finding in AMG 330-treated AML patients. DisclosuresKrupka:AMGEN Inc.: Research Funding. Kufer:AMGEN Inc.: Equity Ownership; AMGEN Research (Munich): Employment. Kischel:AMGEN Inc.: Equity Ownership; AMGEN Research (Munich): Employment. Zugmaier:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Sinclair:AMGEN Inc.: Employment, Equity Ownership. Newhall:AMGEN Inc.: Employment, Equity Ownership. Frankel:AMGEN Inc.: Employment, Equity Ownership. Baeuerle:AMGEN Research (Munich): Employment; AMGEN Inc.: Equity Ownership. Riethmüller:AMGEN Inc.: Equity Ownership. Subklewe:AMGEN Inc.: Research Funding.

Ras Oncoproteins Transfer from Melanoma Cells to T Cells and Modulate Their Effector Functions

Lymphocytes establish dynamic cell-cell interactions with the cells they scan. Previous studies show that upon cell contact, various membrane-associated proteins, such as Ras-family proteins, transfer from B to T and NK lymphocytes. Mutations in RAS genes that encode constitutively active, GTP-bound, oncoproteins are rather common in human cancers; for instance, melanoma. Cancer immunoediting has been postulated to contribute to the elimination of malignant melanoma. Thus, we asked whether Ras oncoproteins can transfer from melanoma to T cells, including tumor-infiltrating lymphocytes (TILs), and subsequently induce functional effects in the adopting T cells. To explore this issue, we genetically engineered an HLA-A2(+) melanoma cell line, MEL526, to express GFP or GFP-tagged H-Ras mutants stably. In this study, we show by an in vitro coculture system that GFP-tagged H-Ras, but not GFP, transfers from MEL526 to T cells and localizes to the inner aspect of their plasma membrane. This cell-contact-dependent process was increased by TCR stimulation and did not require strict Ag specificity. Importantly, we found a positive correlation between the levels of the acquired constitutively active H-RasG12V and ERK1/2 phosphorylation within the adopting TILs. We also show a significant increase in IFN-γ production and cytotoxic activity in TILs that acquired H-RasG12V compared to TILs that acquired a different H-Ras mutant. In conclusion, our findings demonstrate a hitherto unknown phenomenon of intercellular transfer of Ras oncoproteins from melanoma to TILs that consequently augments their effector functions.

Combined immunotherapy with Listeria monocytogenes-based PSA vaccine and radiation therapy leads to a therapeutic response in a murine model of prostate cancer.

Radiation therapy (RT) is an integral part of prostate cancer treatment across all stages and risk groups. Immunotherapy using a live, attenuated, Listeria monocytogenes-based vaccines have been shown previously to be highly efficient in stimulating anti-tumor responses to impact on the growth of established tumors in different tumor models. Here, we evaluated the combination of RT and immunotherapy using Listeria monocytogenes-based vaccine (ADXS31-142) in a mouse model of prostate cancer. Mice bearing PSA-expressing TPSA23 tumor were divided to 5 groups receiving no treatment, ADXS31-142, RT (10Gy), control Listeria vector and combination of ADXS31-142 and RT. Tumor growth curve was generated by measuring the tumor volume biweekly. Tumor tissue, spleen, and sera were harvested from each group for IFN-γ ELISpot, intracellular cytokine assay, tetramer analysis, and immunofluorescence staining. There was a significant tumor growth delay in mice that received combined ADXS31-142 and RT treatment as compared with mice of other cohorts and this combined treatment causes complete regression of their established tumors in 60% of the mice. ELISpot and immunohistochemistry of CD8+cytotoxic T Lymphocytes (CTL) showed a significant increase in IFN-γ production in mice with combined treatment. Tetramer analysis showed a fourfold and a greater than 16-fold increase in PSA-specific CTLs in animals receiving ADXS31-142 alone and combination treatment, respectively. A similar increase in infiltration of CTLs was observed in the tumor tissues. Combination therapy with RT and Listeria PSA vaccine causes significant tumor regression by augmenting PSA-specific immune response and it could serve as a potential treatment regimen for prostate cancer.

Role of TLR ligands in epicutaneously induced contrasuppression

Our previous work showed that epicutaneous (EC) immunization in mice with protein antigen (Ag) induced an Ag-independent unresponsiveness mediated by suppressor CD4+8+ T cells (Ts), which inhibited contact hypersensitivity (CS). Simultaneous EC immunization with Ag and various Toll-like receptor (TLR) ligands reversed skin-induced suppression. Our present study shows that this process activates Ag-specific T contrasuppressor (Tcs) cells and leads to the protection of CS effector T cells from suppression. Epicutaneous immunization with Ag and the TLR4 ligand lipopolysaccharide (LPS) led to a significant increase in IFN-γ production by lymph node and spleen cells. Ag and TLR ligands, like LPS, CpG or lipoteichoic acid did not need to be applied concomitantly to the skin. An identical contrasuppressive effect was observed when the Ag and TLR ligands were deposited on distant skin areas, suggesting that both the generation of Ts and Tcs are independent. To corroborate this finding, we used a model system that uses macrophages (Mf) as Ag-presenting cells. Mf labeled in vitro with Ag (Mf-Ag) induced, upon intravenous (iv) administration, an unresponsiveness reaction that was mediated by Ts cells. When treated simultaneously with LPS-treated Mf (Mf-Ag-LPS), a TLRligand could induce CS. Both the Ag and the LPS signal could be uncoupled i.e., Mf-Ag and Mf-LPS given at separate time points (with an 1h interval between injections) induced immunity.We also found that LPS-treated Mf also produced significant amounts of IL-12, a cytokine that has well-known anti-tolerogenic properties. Our experiments suggest that reversal of EC-induced suppression by TLR-ligands may be a potential tool to increase the immunogenicity of weakly immunogenic antigens.

Effect of chromium on the level of IL-12 and IFN-gamma in occupationally exposed workers

Chromium may affect humoral and cellular immunity, acting on T lymphocytes as well as on granulocytes and monocytes cells. Cytokines play an important role in the immune balance. In this study, the level of IL-12 and IFN-γ were evaluated in the sera and PHA/LPS stimulated culture supernatant of human PBMCs of healthy volunteers and occupationally exposed chromium workers. All the workers were highly exposed to chromium having mean of 104.65 ± 77.21 µg/dL (range 23.7–316.8 µg/dL). A suspension of exposed and unexposed human PBMC (0.5 × 10 6 cells/ml) prepared and cultured in RPMI-1640 supplemented with 10% FCS for 18 h in the presence or absence of LPS (10 ng/ml) which used for stimulation of IL-12 and IFN-γ. The level of IL-12 and IFN-γ were evaluated in the sera samples as well as LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers. In these chromium exposed workers the level of IL-12 was 433.66 ± 197.49 pg/ml and 983.45 ± 330.99 pg/ml in LPS stimulated culture supernatant of normal individuals and highly chromium exposed workers, which was significant ( P < 0.05). Although the level of IL-12 was (78.61 ± 61.03 pg/ml to 146.52 ± 46.37 pg/ml) elevated in unstimulated culture supernatant of h-PBMCs of chromium exposed individuals as compared to control, but it was not significant. This observation also suggests that a significant increase in IFN-γ production in LPS stimulated and unstimulated culture supernatant of h-PBMCs of chromium exposed workers as compared to control. However, IFN-γ level have a significant positive correlation between blood chromium level ( r = 0.833, t = 6.3872, P 0.05) and exposure time (in years) ( r = 0.8916, t = 8.3540, P 0.05) of the occupationally exposed workers.

The activating receptor, NKp30, is important in the interactions between rat natural killer cells and dendritic cells (102.20)

Abstract There is considerable interest in using dendritic cells (DC) to induce transplant tolerance. DC and natural killer (NK) cells have been found to interact in a bi-directional manner. DCs can activate human NK cells to more effectively kill, while NK cells can mediate both maturation and killing of DCs via an NK cell activation receptor, NKp30. NK cells expressing this receptor are elevated post-transplantation prompting us to examine NK cell interactions with DC in a rodent experimental system. Wildtype and rNKp30-transfected RNK-16 cells (rat NK cell line) were co-cultured with bone marrow-derived DCs (BMDC). There was a significant increase in IFNγ production when rNKp30+, but not rNKp30−, NK cells were co-cultured with both immature and mature BMDCs. This NK-DC interaction required cell contact. Flow cytometric analysis of BMDCs with the rNKp30-Fc fusion protein (as compared to a control Fc fusion protein) indicated the presence of rNKp30 ligand(s) on the surface of DCs. Several tumor cell lines also specifically bound rNKp30-Fc. rNKp30-Fc binding was abolished by pretreatment of the tumor cells with trypsin suggesting the ligand is a protein. Furthermore, we established that the expression level of putative rNKp30 ligands correlated with the ability to activate NK cells, as indicated by the levels of IFNγ. Understanding NK cell interactions with DC may suggest potential new targets for tolerance induction.

Effects of Different Tuberculin Skin-Testing Regimens on Gamma Interferon and Antibody Responses in Cattle Experimentally Infected withMycobacterium bovis

Although tuberculin skin testing has been a hallmark of bovine tuberculosis eradication campaigns, it lacks sensitivity, can be confounded by exposure to nontuberculous mycobacteria, and cannot be repeated for 60 days due to desensitization. To overcome these difficulties, an effective whole-blood cellular immunoassay for bovine gamma interferon (IFN-gamma) has been developed. The IFN-gamma test is commonly used in conjunction with tuberculin skin testing as a confirmatory test following a positive response to the caudal fold test (CFT). The present study was conducted to determine the effect of different tuberculin skin-testing regimens on IFN-gamma and antibody production by using calves that were experimentally infected with Mycobacterium bovis. Holstein calves were CFT tested 60 days after inoculation and the comparative cervical test (CCT) was conducted 7 (7-day CCT) or 55 (55-day CCT) days after the CFT. In both the 7-day CCT and 55-day CCT groups, IFN-gamma responses increased 3 days after the CFT; this was immediately followed by a decrease to pre-skin test levels 7 days after the CFT. In both groups, the application of the CCT at 7 or 55 days after the CFT resulted in no significant increase in IFN-gamma production. The administration of the CFT and the CCT to M. bovis-inoculated cattle boosted antibody responses to M. bovis PPD, rMPB83, ESAT-6, and the fusion protein Acr1-MPB83. The boosting effect was more pronounced in the 55-day CCT group. Increases in either IFN-gamma or antibody production were not seen in noninoculated cattle. Measurement of both IFN-gamma and antibody responses after skin testing may be useful in identifying M. bovis-infected cattle; however, the timing of collection of such samples may influence interpretation.

Fine specificity of high molecular weight-melanoma-associated antigen-specific cytotoxic T lymphocytes elicited by anti-idiotypic monoclonal antibodies in patients with melanoma.

HLA-A2-restricted CTLs, which lysed high molecular weight (HMW)-melanoma-associated antigen (MAA)(+) melanoma cells, were induced in patients with melanoma immunized with MELIMMUNE, a combination of the murine anti-idiotypic (anti-id) monoclonal antibodies (mAb) MEL-2 and MF11-30 (MW Pride et al., Clin Cancer Res 1998;4:2363.). In the present study we investigated whether CTL epitopes are present in anti-id mAb MF-11-30 and activate T cells to recognize HMW-MAA on melanoma cells. One candidate epitope in the mAb MF11-30 VH chain, VH (3-11), was selected based on the presence of HLA-A2 anchor residues and partial homology with the HMW-MAA epitope, HMW-MAA (76-84). Lymphocytes from HLA-A2(+)-immunized patients proliferated to VH (3-11) peptide and to a variant HMW-MAA peptide to a significantly greater extent than autologous lymphocytes stimulated with an irrelevant peptide and lymphocytes from nonimmunized patients. No proliferative response was detected to the wild-type HMW-MAA peptide (76-84). Significant increase in IFN-gamma production but not in interleukin 10 production in response to VH (3-11) and to variant HMW-MAA peptide (76-84) was observed in lymphocytes from the immunized patients. Stimulation of lymphocytes from HLA-A2(+) patients with the two peptides induced CTL, which lysed HMW-MAA(+)/HLA-A2(+) A375SM melanoma cells. This is the first report documenting the presence of immunogenic peptides in a murine anti-id mAb for a defined epitope expressed by a human melanoma-associated antigen. These results may be relevant for development of novel vaccines based on homology between anti-id mAb and tumor-associated antigen amino acid sequences.

Interferon gamma production during bovine respiratory syncytial virus (BRSV) infection is diminished in calves vaccinated with formalin-inactivated BRSV

Formalin-inactivated respiratory syncytial virus (FI-RSV) vaccination has been associated with severe disease in humans. Research in mice suggests that FI-RSV may prime for decreased interferon gamma (IFN-γ) production at subsequent infection. Interferon-γ production by peripheral blood mononuclear cells (PBMC) was measured following challenge of calves vaccinated with FI-BRSV to determine whether a similar mechanism is operative in a host naturally susceptible to RSV. Eight-week old male Holstein calves were administered FI-BRSV and mock challenge (V/M, n=6); mock vaccination and BRSV challenge (M/C, n=6) or FI-BRSV and BRSV challenge (V/C, n=7). Vaccine was administered twice at a 2-week interval; challenge followed one month later. On days 0, 5 and 10 postchallenge (PC), PBMC were stimulated in vitro for 24 h with live BRSV, concanavalin A (positive control) or spent media (negative control). Supernatants were assayed for IFN-γ using ELISA. Interferon-γ production by BRSV-stimulated PBMC was increased in M/C and V/C calves as compared to V/M calves on day 5 PC ( p<0.015); and increased in M/C calves compared to V/C and V/M calves on day 10 PC ( p<0.015). Over time postchallenge, a significant increase in IFN-γ production by BRSV-stimulated PBMC was seen in M/C calves ( p<0.025) but not in V/C calves. FI-BRSV vaccination of calves led to diminished IFN-γ production postchallenge. Decreased IFN-γ production may have contributed to impaired viral clearance and enhanced disease in FI-BRSV vaccinated calves.