Factors Influencing Infusion-Related Reactions Following Dosing of Reference Rituximab and PF-05280586, a Rituximab Biosimilar.

BACKGROUND: Infusion-related reactions (IRRs) are the most common adverse event (AE) associated with infusion of rituximab, an anti-CD20 monoclonal antibody. OBJECTIVE: Our objective was to evaluate the impact of dosing/infusion patterns and certain baseline characteristics on IRR occurrence during the first rituximab infusion administered as the biosimilar PF-05280586 (RTX-PF) or reference rituximab sourced from the EU (RTX-EU, MabThera®) in patients with CD20+ low-tumor-burden follicular lymphoma. PATIENTS AND METHODS: Rituximab (RTX-PF, n=196; RTX-EU, n=198) was administered (375 mg/m2) on days 1, 8, 15, and 22 (one cycle), with a follow-up period through 52 weeks. The relationships between infusion rate, drug exposure, and IRR incidence were assessed by logistic regression analysis and pharmacokinetic modeling and simulation. Baseline CD20 level, antidrug antibody (ADA) status, and tumor burden according to IRR occurrence (yes/no) were compared descriptively. RESULTS: Median rituximab infusion duration on day 1 was 3.50 h for each of the two groups. There was a positive correlation between infusion rate and all-grade IRRs occurring within 24 h after infusion (p < 0.0001). Patients who developed IRRs had a higher median baseline CD20+ level. IRR incidence was unaffected by baseline ADA status. Drug exposure did not predict IRR incidence. Baseline tumor burden was similar between patients with and without IRRs. CONCLUSIONS: Results of this analysis provide a better understanding of IRRs after the first rituximab (RTX-PF or RTX-EU) infusion and demonstrate a potential correlation of infusion rate and other factors with IRR at the individual and population levels. Infusion-rate escalation steps continue to be needed to manage IRRs. TRIAL REGISTRATION (DATE OF REGISTRATION): ClinicalTrials.gov Identifier: NCT02213263 (11 August 2014); and EudraCT: 2014-000132-41 (10 October 2014).

Rituximab biosimilars in hematologic malignancies: the need for a real-world approach.

The introduction of rituximab biosimilars into healthcare systems can potentially help to control healthcare costs for the treatment of hematologic malignancies. However, there are currently several barriers to the uptake of biosimilars. This review discusses barriers to the adoption of rituximab biosimilars by stakeholders including patients and healthcare providers. We outline the importance of utilizing real-world evidence in providing additional clinical experience on rituximab biosimilars in hematologic malignancies to improve stakeholder confidence regarding their efficacy and safety. We conclude by offering recommendations for designing and conducting effective real-world studies. Such studies can provide evidence to help achieve lower-priced biologics and improved patient access to help sustain the treatment of hematologic malignancies with biologics, including rituximab biosimilars.

Disseminated tuberculosis and hemophagocytic syndrome although TB prophylaxis in patients with inflammatory bowel disease treated with Infliximab.

PURPOSE: We present de case of a 27-year-old woman admitted to ICU after scheduled splenectomy to study her short course of fever, leukopenia and splenic space-occupying lesions and splenomegaly. She has been previously treated with Infliximab due to indeterminate colitis and completed correct tuberculosis prophylaxis. MATERIALS AND METHODS: We reviewed our case in our regional Electronic Health DataBase IANUS and compared it with other case reports in literature, found in PubMed, with keywords tuberculosis, inflammatory disease and hemophagocytic lymphohistiocytosis. RESULTS: After splenectomy, she needed intensive care due to acute respiratory failure, alveolar-interstitial pulmonary infiltrates, right pleural effusion and fever. Bone marrow aspirate resulted in hemophagocytic lymphohistiocytosis. Only multidisciplinary management in ICU and combined treatment with chemotherapy for hemophagocytic syndrome and tuberculostatics achieved her curation. CONCLUSION: Tuberculosis must always be considered in the differential diagnosis of hemophagocytic lymphohistiocytosis and acute respiratory failure despite correct prior prophylaxis.

An Evidence-based Review of Anti-CD20 Antibody-containing Regimens for the Treatment of Patients With Relapsed or Refractory Chronic Lymphocytic Leukemia, Diffuse Large B-cell Lymphoma, or Follicular Lymphoma.

Combination regimens with anti-CD20 agents might improve the outcomes of patients with relapsed or refractory B-cell malignancies; however, the available comparative clinical evidence is limited. The present review assessed the reported evidence on the efficacy of anti-CD20 monoclonal antibodies combined with chemotherapy for patients with relapsed or refractory chronic lymphocytic leukemia (CLL), follicular lymphoma (FL), or diffuse large B-cell lymphoma (DLBCL), using a rapid evidence assessment approach. MEDLINE, Embase, and the Cochrane Library were searched from January 1, 1997 to July 14, 2017 (English language only). The data identified from randomized controlled trials or single-arm prospective studies are reported as descriptive study summaries, grouped by anti-CD20 agent and outcome (overall response rate, including complete response and partial response; duration of response; survival, including overall survival and progression-free survival). Of 56 included reports, 32 reported on CLL/small lymphocytic lymphoma, 15 on FL, and 11 on DLBCL. Within the study period, 40, 11, and 7 studies evaluated rituximab, ofatumumab, and obinutuzumab, respectively. Substantially more data were available for rituximab-based combination regimens than for either ofatumumab or obinutuzumab. Moreover, substantial heterogeneity was recorded in the study design and backbone chemotherapy. Thus, the available data are inconclusive regarding any potential similarities or differences in efficacy among these anti-CD20 agents for each respective disease. More importantly, only 1 direct comparison among the anti-CD20 agents was identified, emphasizing the need for head-to-head randomized controlled trials of these drugs to inform clinical decision-making for patients with relapsed or refractory B-cell lymphoproliferative disorders.

The Role of Rituximab in Chronic Lymphocytic Leukemia Treatment and the Potential Utility of Biosimilars.

Chronic lymphocytic leukemia (CLL) is managed with observation for asymptomatic or clinically silent disease; pharmacologic intervention is generally required for symptomatic patients with clinically significant adenopathy or cytopenia. In the front-line treatment of CLL, the current standard-of-care includes chemotherapy in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab, or obinutuzumab) or ibrutinib as single agent. Despite the evolving treatment paradigm toward targeted therapy, it is likely that rituximab (plus chemotherapy), with or without targeted agents, will retain a significant role in CLL treatment. However, patents for many biologics, including rituximab, have expired or will expire in the near future. Furthermore, access to rituximab has remained challenging, particularly in countries with restricted resources. Together, these concerns have prompted the development of safe and effective rituximab biosimilars. The term "biosimilar" refers to a biologic that is highly similar to an approved reference (originator) product, notwithstanding minor differences in clinically inactive components, and for which there are no clinically meaningful differences in purity, potency, or safety. Biosimilars are developed to treat the same condition(s) using the same treatment regimens as an approved reference biologic and have the potential to increase access to more affordable treatments. We review the importance of rituximab in the current treatment of CLL, the scientific basis of its future role in combination with chemotherapy, and the role of new and emerging agents in the treatment of CLL, which could potentially be used in combination with rituximab biosimilars. We also discuss rituximab biosimilars currently in development. IMPLICATIONS FOR PRACTICE: Front-line treatments for chronic lymphocytic leukemia (CLL) include chemotherapy in combination with an anti-CD20 monoclonal antibody (e.g., rituximab, ofatumumab, or obinutuzumab) or ibrutinib as single agent. Despite the evolving treatment paradigm, it is likely rituximab (plus chemotherapy) and targeted agents undergoing clinical evaluation will retain a significant role in CLL treatment. However, patents for many biologics, including rituximab, have expired or will expire in the near future and, in many regions, access to rituximab remains challenging. Together, these concerns have prompted the development of safe and effective rituximab biosimilars, with the potential to increase access to more affordable treatments.

The bioleaching potential of a bacterial consortium.

This work presents the molecular foundation of a consortium of five efficient bacteria strains isolated from copper mines currently used in state of the art industrial-scale biotechnology. The strains Acidithiobacillus thiooxidans Licanantay, Acidiphilium multivorum Yenapatur, Leptospirillum ferriphilum Pañiwe, Acidithiobacillus ferrooxidans Wenelen and Sulfobacillus thermosulfidooxidans Cutipay were selected for genome sequencing based on metal tolerance, oxidation activity and bioleaching of copper efficiency. An integrated model of metabolic pathways representing the bioleaching capability of this consortium was generated. Results revealed that greater efficiency in copper recovery may be explained by the higher functional potential of L. ferriphilum Pañiwe and At. thiooxidans Licanantay to oxidize iron and reduced inorganic sulfur compounds. The consortium had a greater capacity to resist copper, arsenic and chloride ion compared to previously described biomining strains. Specialization and particular components in these bacteria provided the consortium a greater ability to bioleach copper sulfide ores.

Global transcriptional responses of Acidithiobacillus ferrooxidans Wenelen under different sulfide minerals.

In order to provide new information about the adaptation of Acidithiobacillus ferrooxidans during the bioleaching process, the current analysis presents the first report of the global transcriptional response of the native copper mine strain Wenelen (DSM 16786) oxidized under different sulfide minerals. Microarrays were used to measure the response of At. ferrooxidans Wenelen to shifts from iron supplemented liquid cultures (reference state) to the addition of solid substrates enriched in pyrite or chalcopyrite. Genes encoding for energy metabolism showed a similar transcriptional profile for the two sulfide minerals. Interestingly, four operons related to sulfur metabolism were over-expressed during growth on a reduced sulfur source. Genes associated with metal tolerance (RND and ATPases type P) were up-regulated in the presence of pyrite or chalcopyrite. These results suggest that At. ferrooxidans Wenelen presents an efficient transcriptional system developed to respond to environmental conditions, namely the ability to withstand high copper concentrations.

Efficacy and safety of sublingual fentanyl tablets for the management of breakthrough pain in patients with chronic musculoskeletal pain with neuropathic component: multicenter prospective study.

BACKGROUND AND OBJECTIVE: Despite its prevalence and impact, breakthrough pain (BTP) in chronic non-cancer pain with neuropathic component, has not been well studied and is sometimes unrecognized and often undertreated. We evaluated the efficacy of sublingual fentanyl tablet (SLF) for the treatment of BTP in opioid-tolerant patients with chronic musculoskeletal pain with neuropathic component in terms of relief of pain intensity and assessed whether hypothetical pain relief impacts on quality of life (QoL). METHODS: A multicenter, prospective, open-label study was conducted over a 30-day period. Efficacy was evaluated using a visual analogue scale (VAS) and time to onset of action of SLF. The incidence of dependence was assessed by the Leeds Dependence Questionnaire (LDQ). Changes in QoL were evaluated using the Brief Pain Questionnaire (BPI) and the EuroQol (EQ-5D). Adverse events (AE) were recorded throughout. RESULTS: 106 patients were enrolled and 105 completed the study. The average pain reduction across the study was -3.30 points [95 % confidence interval (CI) 2.9-3.7; P < 0.0001]. Pain intensity improvement from baseline was statistically significant at first assessment and all subsequent assessments (P < 0.0001). The most common AEs included nausea (33.87 %), constipation (33.06 %), somnolence (19.35 %) and vomiting (6.45 %). No significant differences were observed on LDQ (P = 0.71). QoL as measured by BPI showed statistically significant improvement in all four severity items and all interference items (P < 0.0001) and a significant improvement in the percentage of pain relief reported by patients (P < 0.0001). EQ-5D results showed a trend towards improvement. Mean self-rate health status, as measured by the EQ VAS scale increased significantly (P < 0.0001). CONCLUSION: SLF provides significant reductions in BTP intensity. The results of the BPI and EQ-5D assessments indicate that pain relief is associated with improvement of functioning and enhancement of QoL.

Phase I study of intermittent oral dosing of the insulin-like growth factor-1 and insulin receptors inhibitor OSI-906 in patients with advanced solid tumors.

PURPOSE: We determined the maximum tolerated dose (MTD), safety, pharmacokinetics, pharmacodynamics, and preliminary activity of OSI-906, a potent, oral, dual inhibitor of insulin-like growth factor-1 receptor (IGF1R) and insulin receptor (IR), in patients with advanced solid tumors. EXPERIMENTAL DESIGN: This was a multicenter, open-label, dose escalation phase I study evaluating three intermittent dosing schedules of once-daily OSI-906 [schedule (S) 1, days 1-3 every 14 days; S2, days 1-5 every 14 days; S3, days 1-7 every 14 days]. A fed-fasting expansion cohort was included in the study. RESULTS: Seventy-nine patients were enrolled: 62 in S1, 4 in S2, and 13 in S3. S2 was discontinued. Dose-limiting toxicity comprised grade 3-4 hyperglycemia, vomiting, fatigue, and prolonged QTc interval. The MTD and recommended phase II dose of OSI-906 was 600 mg for both S1 and S3 schedules. Other common adverse events were grade 1-2 nausea, vomiting, fatigue, and diarrhea. The pharmacokinetics of OSI-906 was dose linear, and the terminal half-life ranged between 2 and 6 hours. High-fat meals had a moderate effect on the pharmacokinetics of OSI-906. At the MTD, inhibition of IGF1R and IR was observed in peripheral blood mononuclear cells. An increase in plasma IGF1 concentrations, an indirect measure of IGF1R signaling inhibition, was seen at doses ≥ 450 mg. Two patients with adrenocortical carcinoma achieved partial responses. CONCLUSION: The MTD of 600 mg was well tolerated and associated with preliminary antitumor activity. These data support further evaluation of OSI-906 in solid tumors.

Insights on the structure and stability of Licanantase: a trimeric acid-stable coiled-coil lipoprotein from Acidithiobacillus thiooxidans.

Licanantase (Lic) is the major component of the secretome of Acidithiobacillus thiooxidans when grown in elemental sulphur. When used as an additive, Lic improves copper recovery from bioleaching processes. However, this recovery enhancement is not fully understood. In this context, our aim is to predict the 3D structure of Lic, to shed light on its structure-function relationships. Bioinformatics analyses on the amino acid sequence of Lic showed a great similarity with Lpp, an Escherichia coli Lipoprotein that can form stable trimers in solution. Lic and Lpp share the secretion motif, intracellular processing and alpha helix structure, as well as the distribution of hydrophobic residues in heptads forming a hydrophobic core, typical of coiled-coil structures. Cross-linking experiments showed the presence of Lic trimers, supporting our predictions. Taking the in vitro and in silico evidence as a whole, we propose that the most probable structure for Lic is a trimeric coiled-coil. According to this prediction, a suitable model for Lic was produced using the de novo algorithm "Rosetta Fold-and-Dock". To assess the structural stability of our model, Molecular Dynamics (MD) and Replica Exchange MD simulations were performed using the structure of Lpp and a 14-alanine Lpp mutant as controls, at both acidic and neutral pH. Our results suggest that Lic was the most stable structure among the studied proteins in both pH conditions. This increased stability can be explained by a higher number of both intermonomer hydrophobic contacts and hydrogen bonds, key elements for the stability of Lic's secondary and tertiary structure.

A new genome of Acidithiobacillus thiooxidans provides insights into adaptation to a bioleaching environment.

Acidithiobacillus thiooxidans is a sulfur oxidizing acidophilic bacterium found in many sulfur-rich environments. It is particularly interesting due to its role in bioleaching of sulphide minerals. In this work, we report the genome sequence of At. thiooxidans Licanantay, the first strain from a copper mine to be sequenced and currently used in bioleaching industrial processes. Through comparative genomic analysis with two other At. thiooxidans non-metal mining strains (ATCC 19377 and A01) we determined that these strains share a large core genome of 2109 coding sequences and a high average nucleotide identity over 98%. Nevertheless, the presence of 841 strain-specific genes (absent in other At. thiooxidans strains) suggests a particular adaptation of Licanantay to its specific biomining environment. Among this group, we highlight genes encoding for proteins involved in heavy metal tolerance, mineral cell attachment and cysteine biosynthesis. Several of these genes were located near genetic motility genes (e.g. transposases and integrases) in genomic regions of over 10 kbp absent in the other strains, suggesting the presence of genomic islands in the Licanantay genome probably produced by horizontal gene transfer in mining environments.

Sulfobacillus thermosulfidooxidans strain Cutipay enhances chalcopyrite bioleaching under moderate thermophilic conditions in the presence of chloride ion.

Currently more than 90% of the world's copper is obtained through sulfide mineral processing. Among the copper sulfides, chalcopyrite is the most abundant and therefore economically relevant. However, primary copper sulfide bioleaching is restricted due to high ionic strength raffinate solutions and particularly chloride coming from the dissolution of ores. In this work we describe the chalcopyrite bioleaching capacity of Sulfobacillus thermosulfidooxidans strain Cutipay (DSM 27601) previously described at the genomic level (Travisany et al. (2012) Draft genome sequence of the Sulfobacillus thermosulfidooxidans Cutipay strain, an indigenous bacterium isolated from a naturally extreme mining environment in Northern Chile. J Bacteriol 194:6327-6328). Bioleaching assays with the mixotrophic strain Cutipay showed a strong increase in copper recovery from chalcopyrite concentrate at 50°C in the presence of chloride ion, a relevant inhibitory element present in copper bioleaching processes. Compared to the abiotic control and a test with Sulfobacillus acidophilus DSM 10332, strain Cutipay showed an increase of 42 and 69% in copper recovery, respectively, demonstrating its high potential for chalcopyrite bioleaching. Moreover, a genomic comparison highlights the presence of the 2-Haloacid dehalogenase predicted-protein related to a potential new mechanism of chloride resistance in acidophiles. This novel and industrially applicable strain is under patent application CL 2013-03335.

Stoichiometric modeling of oxidation of reduced inorganic sulfur compounds (Riscs) in Acidithiobacillus thiooxidans.

The prokaryotic oxidation of reduced inorganic sulfur compounds (RISCs) is a topic of utmost importance from a biogeochemical and industrial perspective. Despite sulfur oxidizing bacterial activity is largely known, no quantitative approaches to biological RISCs oxidation have been made, gathering all the complex abiotic and enzymatic stoichiometry involved. Even though in the case of neutrophilic bacteria such as Paracoccus and Beggiatoa species the RISCs oxidation systems are well described, there is a lack of knowledge for acidophilic microorganisms. Here, we present the first experimentally validated stoichiometric model able to assess RISCs oxidation quantitatively in Acidithiobacillus thiooxidans (strain DSM 17318), the archetype of the sulfur oxidizing acidophilic chemolithoautotrophs. This model was built based on literature and genomic analysis, considering a widespread mix of formerly proposed RISCs oxidation models combined and evaluated experimentally. Thiosulfate partial oxidation by the Sox system (SoxABXYZ) was placed as central step of sulfur oxidation model, along with abiotic reactions. This model was coupled with a detailed stoichiometry of biomass production, providing accurate bacterial growth predictions. In silico deletion/inactivation highlights the role of sulfur dioxygenase as the main catalyzer and a moderate function of tetrathionate hydrolase in elemental sulfur catabolism, demonstrating that this model constitutes an advanced instrument for the optimization of At. thiooxidans biomass production with potential use in biohydrometallurgical and environmental applications.

Metabolomic study of Chilean biomining bacteria Acidithiobacillus ferrooxidans strain Wenelen and Acidithiobacillus thiooxidans strain Licanantay.

In this study, we present the first metabolic profiles for two bioleaching bacteria using capillary electrophoresis coupled with mass spectrometry. The bacteria, Acidithiobacillus ferrooxidans strain Wenelen (DSM 16786) and Acidithiobacillus thiooxidans strain Licanantay (DSM 17318), were sampled at different growth phases and on different substrates: the former was grown with iron and sulfur, and the latter with sulfur and chalcopyrite. Metabolic profiles were scored from planktonic and sessile states. Spermidine was detected in intra- and extracellular samples for both strains, suggesting it has an important role in biofilm formation in the presence of solid substrate. The canonical pathway for spermidine synthesis seems absent as its upstream precursor, putrescine, was not present in samples. Glutathione, a catalytic activator of elemental sulfur, was identified as one of the most abundant metabolites in the intracellular space in A. thiooxidans strain Licanantay, confirming its participation in the sulfur oxidation pathway. Amino acid profiles varied according to the growth conditions and bioleaching species. Glutamic and aspartic acid were highly abundant in intra- and extracellular extracts. Both are constituents of the extracellular matrix, and have a probable role in cell detoxification. This novel metabolomic information validates previous knowledge from in silico metabolic reconstructions based on genomic sequences, and reveals important biomining functions such as biofilm formation, energy management and stress responses. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s11306-012-0443-3) contains supplementary material, which is available to authorized users.

Draft genome sequence of the Sulfobacillus thermosulfidooxidans Cutipay strain, an indigenous bacterium isolated from a naturally extreme mining environment in Northern Chile.

Sulfobacillus thermosulfidooxidans strain Cutipay is a mixotrophic, acidophilic, moderately thermophilic bacterium isolated from mining environments of the north of Chile, making it an interesting subject for studying the bioleaching of copper. We introduce the draft genome sequence and annotation of this strain, which provide insights into its mechanisms for heavy metal resistance.

Acidithiobacillus thiooxidans secretome containing a newly described lipoprotein Licanantase enhances chalcopyrite bioleaching rate.

The nature of the mineral-bacteria interphase where electron and mass transfer processes occur is a key element of the bioleaching processes of sulfide minerals. This interphase is composed of proteins, metabolites, and other compounds embedded in extracellular polymeric substances mainly consisting of sugars and lipids (Gehrke et al., Appl Environ Microbiol 64(7):2743-2747, 1998). On this respect, despite Acidithiobacilli-a ubiquitous bacterial genera in bioleaching processes (Rawlings, Microb Cell Fact 4(1):13, 2005)-has long been recognized as secreting bacteria (Jones and Starkey, J Bacteriol 82:788-789, 1961; Schaeffer and Umbreit, J Bacteriol 85:492-493, 1963), few studies have been carried out in order to clarify the nature and the role of the secreted protein component: the secretome. This work characterizes for the first time the sulfur (meta)secretome of Acidithiobacillus thiooxidans strain DSM 17318 in pure and mixed cultures with Acidithiobacillus ferrooxidans DSM 16786, identifying the major component of these secreted fractions as a single lipoprotein named here as Licanantase. Bioleaching assays with the addition of Licanantase-enriched concentrated secretome fractions show that this newly found lipoprotein as an active protein additive exerts an increasing effect on chalcopyrite bioleaching rate.

Comparative genomic analysis of carbon and nitrogen assimilation mechanisms in three indigenous bioleaching bacteria: predictions and validations.

BACKGROUND: Carbon and nitrogen fixation are essential pathways for autotrophic bacteria living in extreme environments. These bacteria can use carbon dioxide directly from the air as their sole carbon source and can use different sources of nitrogen such as ammonia, nitrate, nitrite, or even nitrogen from the air. To have a better understanding of how these processes occur and to determine how we can make them more efficient, a comparative genomic analysis of three bioleaching bacteria isolated from mine sites in Chile was performed. This study demonstrated that there are important differences in the carbon dioxide and nitrogen fixation mechanisms among bioleaching bacteria that coexist in mining environments. RESULTS: In this study, we probed that both Acidithiobacillus ferrooxidans and Acidithiobacillus thiooxidans incorporate CO2 via the Calvin-Benson-Bassham cycle; however, the former bacterium has two copies of the Rubisco type I gene whereas the latter has only one copy. In contrast, we demonstrated that Leptospirillum ferriphilum utilizes the reductive tricarboxylic acid cycle for carbon fixation. Although all the species analyzed in our study can incorporate ammonia by an ammonia transporter, we demonstrated that Acidithiobacillus thiooxidans could also assimilate nitrate and nitrite but only Acidithiobacillus ferrooxidans could fix nitrogen directly from the air. CONCLUSION: The current study utilized genomic and molecular evidence to verify carbon and nitrogen fixation mechanisms for three bioleaching bacteria and provided an analysis of the potential regulatory pathways and functional networks that control carbon and nitrogen fixation in these microorganisms.

Reprogrammed FoxP3+ T regulatory cells become IL-17+ antigen-specific autoimmune effectors in vitro and in vivo.

Lymphocyte differentiation from naive CD4(+) T cells into mature Th1, Th2, Th17, or T regulatory cell (Treg) phenotypes has been considered end stage in character. In this study, we demonstrate that dendritic cells (DCs) activated with a novel immune modulator B7-DC XAb (DC(XAb)) can reprogram Tregs into T effector cells. Down-regulation of FoxP3 expression after either in vitro or in vivo Treg-DC(XAb) interaction is Ag-specific, IL-6-dependent, and results in the functional reprogramming of the mature T cell phenotype. The reprogrammed Tregs cease to express IL-10 and TGFbeta, fail to suppress T cell responses, and gain the ability to produce IFN-gamma, IL-17, and TNF-alpha. The ability of IL-6(+) DC(XAb) and the inability of IL-6(-/-) DC(XAb) vaccines to protect animals from lethal melanoma suggest that exogenously modulated DC can reprogram host Tregs. In support of this hypothesis and as a test for Ag specificity, transfer of DC(XAb) into RIP-OVA mice causes a break in immune tolerance, inducing diabetes. Conversely, adoptive transfer of reprogrammed Tregs but not similarly treated CD25(-) T cells into naive RIP-OVA mice is also sufficient to cause autoimmune diabetes. Yet, treatment of normal mice with B7-DC XAb fails to elicit generalized autoimmunity. The finding that mature Tregs can be reprogrammed into competent effector cells provides new insights into the plasticity of T cell lineage, underscores the importance of DC-T cell interaction in balancing immunity with tolerance, points to Tregs as a reservoir of autoimmune effectors, and defines a new approach for breaking tolerance to self Ags as a strategy for cancer immunotherapy.