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BACKGROUND: Chemotherapy is the standard of care for advanced stages of non-small-cell lung cancer (NSCLC). TG4010 is a targeted immunotherapy based on a poxvirus (modified vaccinia virus Ankara) that codes for MUC1 tumour-associated antigen and interleukin 2. This study assessed TG4010 in combination with first-line chemotherapy in advanced NSCLC. METHODS: 148 patients with advanced (stage IIIB [wet] or IV) NSCLC expressing MUC1 by immunohistochemistry, and with performance status 0 or 1, were enrolled in parallel groups in this open-label, phase 2B study. 74 patients were allocated to the combination therapy group, and received TG4010 (10(8) plaque forming units) plus cisplatin (75 mg/m(2) on day 1) and gemcitabine (1250 mg/m(2) on days 1 and 8) repeated every 3 weeks for up to six cycles. 74 patients allocated to the control group received the same chemotherapy alone. Patients were allocated using a dynamic minimisation procedure stratified by centre, performance status, and disease stage. The primary endpoint was 6-month progression-free survival (PFS), with a target rate of 40% or higher in the experimental group. Analyses were done on an intention-to-treat basis. This study is completed and is registered with ClinicalTrials.gov, number NCT00415818. FINDINGS: 6-month PFS was 43·2% (32 of 74; 95% CI 33·4-53·5) in the TG4010 plus chemotherapy group, and 35·1% (26 of 74; 25·9-45·3) in the chemotherapy alone group. Fever, abdominal pain, and injection-site pain of any grade according to National Cancer Institute Common Toxicity Criteria were more common in the TG4010 group than in the chemotherapy alone group: 17 of 73 patients (23·3%) versus six of 72 (8·3%), 12 (16·4%) versus two (2·8%), and four (5·5%) versus zero (0%), respectively. The most common grade 3-4 adverse events were neutropenia (33 [45·2%] of patients in the TG4010 plus chemotherapy group vs 31 [43·1%] in the chemotherapy alone group) and fatigue (18 [24·7%] vs 13 [18·1%]); the only grade 3-4 events that differed significantly between groups were anorexia (three [4·1%] vs 10 [13·9%]) and pleural effusion (none vs four [5·6%]). 38 of 73 patients (52·1%) in the TG4010 plus chemotherapy group and 34 of 72 (47·2%) in the chemotherapy alone group had at least one serious adverse event. INTERPRETATION: This phase 2B study suggests that TG4010 enhances the effect of chemotherapy in advanced NSCLC. A confirmatory phase 2B-3 trial has been initiated. FUNDING: Transgene SA, Advanced Diagnostics for New Therapeutic Approaches (ADNA)/OSEO. [ABSTRACT FROM AUTHOR]

Thiols are among the most frequently used functional groups in the field of bioconjugation. While there exists a variety of heterobifunctional reagents that allow for coupling thiols to other functions (e.g., amines, carboxylic acids), there is no specific reagent for creating heteroconjugates using two different thiols. In response to the ever-increasing demand for bioconjugation tools, we have developed p-(maleimide)-phenylpropionitrile (MAPN)-an efficient reagent for kinetically resolved thiol-to-thiol coupling. In a comparative study with its closest commercially available analogue, p-phenylenedimaleimide, MAPN has shown substantial advantages for the preparation of thiol-thiol heteroconjugates. Namely, an antibody-drug conjugate (ADC) with mertansine (DM1), conjugated to the cysteine residues of Trastuzumab, was prepared for the first time.

Amine-to-thiol coupling is the most common route for the preparation of antibody-drug conjugates (ADC). It is usually achieved by using heterobifunctional reagents possessing an activated ester at one end and a maleimide group at the other. However, maleimide-based conjugates were recently revealed to have limited stability in blood circulation, which can compromise therapeutic efficacy of the conjugate. To address this issue, we have developed a heterobifunctional reagent, sodium 4-((4-(cyanoethynyl)benzoyl)oxy)-2,3,5,6-tetrafluorobenzenesulfonate (CBTF), for amine-to-thiol coupling. It comprises a recently described 3-arylpropionitrile (APN) function in replacement of maleimide and allows for the preparation of remarkably stable conjugates. A series of antibody-dye conjugates have been prepared using this reagent and shown superior stability in human blood plasma compared to maleimide-derived conjugates.

Objective: Colony-stimulating factor 1 receptor (CSF-1R) essentially modulates monocyte proliferation, migration, and activation, which are considered important for the pathogenesis of rheumatoid arthritis (RA). We undertook this study to determine CSF-1R expression in human RA as well as the efficacy of a specific anti-CSF-1R monoclonal antibody (AFS98) in 2 different animal models of RA., Methods: CSF-1R expression was examined in blood, synovium, and bone samples from RA patients, osteoarthritis (OA) patients, and healthy subjects. The efficacy of AFS98 was examined by clinical assessment, histology, and bone histomorphometry in collagen-induced arthritis (CIA) and serum-transfer arthritis., Results: CSF-1R expression was increased in the synovium of RA patients compared to OA patients and healthy controls in fibroblast-like synoviocytes, follicular dendritic cells, macrophages, and osteoclasts. Circulating RA monocytes and neutrophils but not lymphocytes were CSF-1R+. In mice, blockade of CSF-1R abrogated cartilage damage, bone erosion, and systemic bone loss, and this was associated with the depletion of osteoclasts in both models. While blockade of CSF-1R did not affect inflammation in passive serum-transfer arthritis, it significantly reduced inflammation in CIA, and this was associated with the absence of synovial macrophages and reduced splenic CD11b+Gr-1- monocytes., Conclusion: CSF-1R was broadly expressed in human RA. Blockade of CSF-1R protected against bone and cartilage destruction in both mouse models and also showed significant antiinflammatory effects in the CIA model. These data provide evidence for CSF-1R as a therapeutic target in RA., (Copyright © 2014 by the American College of Rheumatology.)

Unlabelled: To identify novel stimulators of the innate immune system, we constructed a panel of eight HEK293 cell lines double positive for human Toll-like receptors (TLRs) and an NF-κB-inducible reporter gene. Screening of a large variety of compounds and cellular extracts detected a TLR3-activating compound in a microsomal yeast extract. Fractionation of this extract identified an RNA molecule of 4.6 kb, named nucleic acid band 2 (NAB2), that was sufficient to confer the activation of TLR3. Digests with single- and double-strand-specific RNases showed the double-strand nature of this RNA, and its sequence was found to be identical to that of the genome of the double-stranded RNA (dsRNA) L-BC virus of Saccharomyces cerevisiae. A large-scale process of production and purification of this RNA was established on the basis of chemical cell lysis and dsRNA-specific chromatography. NAB2 complexed with the cationic lipid Lipofectin but neither NAB2 nor Lipofectin alone induced the secretion of interleukin-12(p70) [IL-12(p70)], alpha interferon, gamma interferon-induced protein 10, macrophage inflammatory protein 1β, or IL-6 in human monocyte-derived dendritic cells. While NAB2 activated TLR3, Lipofectin-stabilized NAB2 also signaled via the cytoplasmic sensor for RNA recognition MDA-5. A significant increase of RMA-MUC1 tumor rejection and survival was observed in C57BL/6 mice after prophylactic vaccination with MUC1-encoding modified vaccinia virus Ankara (MVA) and NAB2-Lipofectin. This combination of immunotherapies strongly increased at the injection sites the percentage of infiltrating natural killer (NK) cells and plasmacytoid dendritic cells (pDCs), cell types which can modulate innate and adaptive immune responses., Importance: Virus-based cancer vaccines offer a good alternative to the treatment of cancer but could be improved. Starting from a screening approach, we have identified and characterized an unexplored biological molecule with immunomodulatory characteristics which augments the efficacy of an MVA-based immunotherapeutic agent. The immune modulator consists of the purified dsRNA genome isolated from a commercially used yeast strain, NAB2, mixed with a cationic lipid, Lipofectin. NAB2-Lipofectin stimulates the immune system via TLR3 and MDA-5. When it was injected at the MVA vaccination site, the immune modulator increased survival in a preclinical tumor model. We could demonstrate that NAB2-Lipofectin augments the MVA-induced infiltration of natural killer and plasmacytoid dendritic cells. We suggest indirect mechanisms of activation of these cell types by the influence of NAB2-Lipofectin on innate and adaptive immunity. Detailed analysis of cell migration at the vaccine injection site and the appropriate choice of an immune modulator should be considered to achieve the rational improvement of virus vector-based vaccination by immune modulators.

The humanized monoclonal antibody H27K15 specifically targets human CD115, a type III tyrosine kinase receptor involved in multiple cancers and inflammatory diseases. Binding of H27K15 to hCD115 expressing cells inhibits the functional effect of colony-stimulating factor-1 (CSF-1), in a non-competitive manner. Both homology modeling and docking programs were used here to model the human CD115 extracellular domains, the H27K15 variable region and their interaction. The resulting predicted H27K15 epitope includes mainly the D1 domain in the N-terminal extracellular region of CD115 and some residues of the D2 domain. Sequence alignment with the non-binding murine CD115, enzyme-linked immunosorbent assay, nuclear magnetic resonance spectroscopy and affinity measurements by quartz crystal microbalance revealed critical residues of this epitope that are essential for H27K15 binding. A combination of computational simulations and biochemical experiments led to the design of a chimeric CD115 carrying the human epitope of H27K15 in a murine CD115 backbone that is able to bind both H27K15 as well as the murine ligands CSF-1 and IL-34. These results provide new possibilities to minutely study the functional effects of H27K15 in a transgenic mouse that would express this chimeric molecule.

Women showing normal cytology but diagnosed with a persistent high-risk human papillomavirus (HR-HPV) infection have a higher risk of developing high-grade cervical intraepithelial neoplasia and cervical cancer than noninfected women. As no therapeutic management other than surveillance is offered to these women, there is a major challenge to develop novel targeted therapies dedicated to the treatment of these patients. As such, E1 and E2 antigens, expressed early in the HPV life cycle, represent very interesting candidates. Both proteins are necessary for maintaining coordinated viral replication and gene synthesis during the differentiation process of the epithelium and are essential for the virus to complete its normal and propagative replication cycle. In the present study, we evaluated a new active targeted immunotherapeutic, a modified vaccinia virus Ankara (MVA) vector containing the E1 sequence of HPV16, aimed at inducing cellular immune responses with the potential to help and clear persistent HPV16-related infection. We carried out an extensive comparative time course analysis of the cellular immune responses induced by different schedules of immunization in C57BL/6 mice. We showed that multiple injections of MVA-E1 allowed sustained HPV16 E1-specific cellular immune responses in vaccinated mice and had no impact on the exhaustion phenotype of the generated HPV16 E1-specific CD8⁺ T cells, but they led to the differentiation of multifunctional effector T cells with high cytotoxic capacity. This study provides proof of concept that an MVA expressing HPV16 E1 can induce robust and long-lasting E1-specific responses and warrants further development of this candidate.

Background: Primary cutaneous lymphomas (CLs), characterized by an accumulation of clonal T or B lymphocytes preferentially localized in the skin, have been successfully treated with interferons (IFNs) which counterbalance the Th2-immunosuppressive state associated with this pathology. In a phase I/II clinical trial, we correlated the local immune infiltrate and the anti-tumor effects of repeated intralesional administrations of an adenovirus vector expressing human interferon-gamma (IFN-g) termed TG1042, in patients with advanced primary cutaneous T-cell lymphomas (CTCL) or multilesional cutaneous B-cell lymphomas (CBCL)., Methods: For each patient, variation in time of specific lymphocyte populations, defined by immunohistochemical stainings, was assessed in biopsies of injected lesions. For each patient, the change in local immune response was associated with the patient's objective response at the end of the study., Results: Immunohistochemical analyses of biopsies indicate that infiltration of CD8+ T lymphocytes and of TIA-1+ cytotoxic T-cells in lesions injected with TG1042 correlates with clinical benefit., Conclusions: These data suggest for the first time that a CD8+ cytotoxic infiltrate, induced by local expression of IFN-g correlates with a clinical response., Trial Registration: The phase I step (TG1042.01) does not have a registration number. The phase II step (TG1042.06) registration number was NCT00394693.

Tumor progression is promoted by Tumor-Associated Macrophages (TAMs) and metastasis-induced bone destruction by osteoclasts. Both myeloid cell types depend on the CD115-CSF-1 pathway for their differentiation and function. We used 3 different mouse cancer models to study the effects of targeting cancer host myeloid cells with a monoclonal antibody (mAb) capable of blocking CSF-1 binding to murine CD115. In mice bearing sub-cutaneous EL4 tumors, which are CD115-negative, the anti-CD115 mAb depleted F4/80(+) CD163(+) M2-type TAMs and reduced tumor growth, resulting in prolonged survival. In the MMTV-PyMT mouse model, the spontaneous appearance of palpable mammary tumors was delayed when the anti-CD115 mAb was administered before malignant transition and tumors became palpable only after termination of the immunotherapy. When administered to mice already bearing established PyMT tumors, anti-CD115 treatment prolonged their survival and potentiated the effect of chemotherapy with Paclitaxel. As shown by immunohistochemistry, this therapeutic effect correlated with the depletion of F4/80(+)CD163(+) M2-polarized TAMs. In a breast cancer model of bone metastasis, the anti-CD115 mAb potently blocked the differentiation of osteoclasts and their bone destruction activity. This resulted in the inhibition of cancer-induced weight loss. CD115 thus represents a promising target for cancer immunotherapy, since a specific blocking antibody may not only inhibit the growth of a primary tumor through TAM depletion, but also metastasis-induced bone destruction through osteoclast inhibition.

Cancer progression has been associated with the presence of tumor-associated M2-macrophages (M2-TAMs) able to inhibit anti-tumor immune responses. It is also often associated with metastasis-induced bone destruction mediated by osteoclasts. Both cell types are controlled by the CD115 (CSF-1R)/colony-stimulating factor-1 (CSF-1, M-CSF) pathway, making CD115 a promising target for cancer therapy. Anti-human CD115 monoclonal antibodies (mAbs) that inhibit the receptor function have been generated in a number of laboratories. These mAbs compete with CSF-1 binding to CD115, dramatically affecting monocyte survival and preventing osteoclast and macrophage differentiation, but they also block CD115/CSF-1 internalization and degradation, which could lead to potent rebound CSF-1 effects in patients after mAb treatment has ended. We thus generated and selected a non-ligand competitive anti-CD115 mAb that exerts only partial inhibitory effects on CD115 signaling without blocking the internalization or the degradation of the CD115/CSF-1 complex. This mAb, H27K15, affects monocyte survival only minimally, but downregulates osteoclast differentiation and activity. Importantly, it inhibits monocyte differentiation to CD163(+)CD64(+) M2-polarized suppressor macrophages, skewing their differentiation toward CD14(-)CD1a(+) dendritic cells (DCs). In line with this observation, H27K15 also drastically inhibits monocyte chemotactic protein-1 secretion and reduces interleukin-6 production; these two molecules are known to be involved in M2-macrophage recruitment. Thus, the non-depleting mAb H27K15 is a promising anti-tumor candidate, able to inhibit osteoclast differentiation, likely decreasing metastasis-induced osteolysis, and able to prevent M2 polarization of TAMs while inducing DCs, hence contributing to the creation of more efficient anti-tumor immune responses.

Background: We explored the concept of heterologous prime/boost vaccination using 2 therapeutic vaccines currently in clinical development aimed at treating chronically infected hepatitis C virus (HCV) patients: prime with a DNA-based vaccine expressing HCV genotype 1a NS3/4A proteins (ChronVac-C) and boost with a modified vaccinia virus Ankara vaccine expressing genotype 1b NS3/4/5B proteins (MVATG16643)., Methods: Two ChronVac-C immunizations 4 weeks apart were delivered intramuscularly in combination with in vivo electroporation and subsequently 5 or 12 weeks later boosted by 3 weekly subcutaneous injections of MVATG16643. Two mouse strains were used, and we evaluated quality, magnitude, and functionality of the T cells induced., Results: DNA prime/MVA boost regimen induced significantly higher levels of interferon γ (IFN-γ) or interleukin 2 (IL-2) ELISpot responses compared with each vaccine alone, independent of the time of analysis and the time interval between vaccinations. Both CD8⁺ and CD4⁺ T-cell responses as well as the spectrum of epitopes recognized was improved. A significant increase in polyfunctional IFN-γ/tumor necrosis factor α (TNF-α)/CD107a⁺ CD8⁺ T cells was detected following ChronVac-C/MVATG16643 vaccination (from 3% to 25%), and prime/boost was the only regimen that activated quadrifunctional T cells (IFN-γ/TNF-α/CD107a/IL-2). In vivo functional protective capacity of DNA prime/MVA boost was demonstrated in a Listeria-NS3-1a challenge model., Conclusions: We provide a proof-of-concept that immunogenicity of 2 HCV therapeutic vaccines can be improved using their combination, which merits further clinical development.

Therapeutic vaccines are different from the well-known prophylactic vaccines in that they are designed to treat patients already suffering from a disease instead of preventing the disease in healthy individuals. Several therapeutic vaccines are today in late-stage clinical development for non-small-cell lung cancer. These vaccines use different approaches including peptides, cell lines and viral vectors, and explore different settings within the pathology. Some are given in monotherapy while others are combined with the classic therapies used with non-small-cell lung cancer. This review gives a summary of the therapeutic vaccines currently in late-stage clinical development for non-small-cell lung cancer.

Cancer immunotherapy is hampered by the immunosuppression maintained by regulatory T cells (Tregs) in tumor-bearing hosts. Stimulation of the Toll-like receptor 2 (TLR2) by Pam3Cys is known to affect Treg-mediated suppression. We found that Pam3Cys increases the proliferation of both CD4(+) effector T cells (Teffs) and Tregs co-cultured in vitro, but did not induce the proliferation of Tregs alone upon CD3 and CD28 stimulation. In a mouse model of RMA-MUC1 tumors, Pam3Cys was administered either alone or in combination with a modified vaccinia ankara (MVA)-based mucin 1 (MUC1) therapeutic vaccine. The combination of Pam3Cys with MVA-MUC1 (1) diminished splenic Treg/CD4(+) T-cell ratios to those found in tumor-free mice, (2) stimulated a specific anti-MUC1 interferon γ (IFNγ) response and (3) had a significant therapeutic effect on tumor growth and mouse survival. When CD4(+) Teffs and Tregs were isolated from Pam3Cys-treated mice, Teffs had become resistant to Treg-mediated suppression while upregulating the expression of BclL-x(L). Tregs from Pam3Cys-treated mice were fully suppressive for Teffs from naïve mice. Bcl-x(L) was induced by Pam3Cys with different kinetics in Tregs and Teffs. Teff from Pam3Cys-treated mice produced increased levels of Th1 and Th2-type cytokines and an interleukin (IL)-6-dependent secretion of IL-17 was observed in Teff:Treg co-cultures, suggesting that TLR2 stimulation had skewed the immune response toward a Th17 profile. Our results show for the first time that in a tumor-bearing host, TLR2 stimulation with Pam3Cys affects both Tregs and Teffs, protects Teff from Treg-mediated suppression and has strong therapeutic effects when combined with an MVA-based antitumor vaccine.

Immunotherapy of cancer has long been considered as an attractive therapeutic approach but with no impact on clinical practice. Two clinical protocols of immunotherapy, one based on a cancer vaccine in patients with prostate cancer or melanoma and the other using an immunomodulator targeting T cells (anti-CTLA4 mAb) in melanoma patients, have demonstrated clinical efficacy in two phase III clinical trials. To improve these encouraging clinical results, biomarkers to better select patients which may benefit from this therapy are actively searched. In addition, immunosuppression associated with cancer has to be overcome to allow a better immunostimulation. In contrast to chemotherapy, clinical variables to monitor the efficacy of immunotherapy has to be revisited and overall survival appears to be a better endpoint than clinical response defined by the RECIST criteria. Combination of immunotherapy with conventional treatments (chemotherapy, anti-angiogenic, etc.) should further improve this approach both in its effectiveness and in its clinical indications., (© 2011 médecine/sciences – Inserm / SRMS.)

Background & Aims: Therapy for chronic hepatitis C (CHC) has limited efficacy, adverse effects, and high costs. Cohort and vaccine-based preclinical studies have indicated the importance of T-cell-based immunity in controlling viral infection. TG4040 is a recombinant poxvirus vaccine that expresses the hepatitis C virus (HCV) proteins NS3, NS4, and NS5B. We performed a phase I clinical trial to assess the safety, immunogenicity, and early antiviral efficacy of TG4040 in patients with CHC., Methods: In an open-label, dose-escalating study, patients with mild CHC (genotype 1) were assigned to 3 groups of 3 patients each; they received subcutaneous injections of 10⁶, 10⁷, or 10⁸ plaque-forming units of TG4040 on study days 1, 8, and 15. Six additional patients were given the highest dose of vaccine (10⁸ plaque-forming units). Patients were followed for 6 months after the last injection. T-cell-based and antibody responses and levels of HCV RNA were measured., Results: All 3 doses of TG4040 were well tolerated, without serious adverse events. Vaccine-induced HCV-specific cellular immune responses were observed in 5 of the 15 patients (33%). A transient decrease in circulating levels of HCV RNA, from -0.52 log₁₀ to -1.24 log₁₀, was observed in 8 patients; in 5 patients, the lowest level of HCV RNA was observed on day 37, after the first injection. The most pronounced decrease in viral load occurred in 2 patients, who also had marked vaccine-induced T-cell responses., Conclusions: In patients with CHC, the viral-vector-based vaccine TG4040 had a good safety profile, induced HCV-specific cellular immune responses, and reduced viral load. This vaccine should be investigated in further clinical studies, in combination with standard of care., (Copyright © 2011 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Tumor-associated antigens (TAAs) have been formulated into vaccines that, combined with adjuvants, cytokines or other strategies to boost the immune response, are now in clinical development. Both humoral and cellular immune responses to TAAs have been generated using these vaccines. This approach relies on the patient's own immune system generating an effective anti-tumor immune response. The advantage of this over therapy with monoclonal antibodies for the treatment of cancer is that multiple antigenic epitopes can be involved and the immune system is able to adapt to the most effective antigenic specificity for tumor growth control and rejection. In this article, we describe the clinical use of vaccinia virus, in particular modified vaccinia virus Ankara (MVA), to express TAAs in vivo and to stimulate an effective immune response to the cancer antigens.

CD23 is a type II transmembrane glycoprotein synthesized by hematopoietic cells that has biological activity in both membrane-bound and freely soluble forms, acting via a number of receptors, including integrins. We demonstrate here that soluble CD23 (sCD23) sustains growth of human B cell precursors via an RGD-independent interaction with the alphavbeta5 integrin. The integrin recognizes a tripeptide motif in a small disulfide-bonded loop at the N terminus of the lectin head region of CD23, centered around Arg(172), Lys(173), and Cys(174) (RKC). This RKC motif is present in all forms of sCD23 with cytokine-like activity, and cytokine activity is independent of the lectin head, an "inverse RGD" motif, and the CD21 and IgE binding sites. RKC-containing peptides derived from this region of CD23 bind alphavbeta5 and are biologically active. The binding and activity of these peptides is unaffected by inclusion of a short peptide containing the classic RGD sequence recognized by integrins, and, in far-Western analyses, RKC-containing peptides bind to the beta subunit of the alphavbeta5 integrin. The interaction between alphavbeta5 and sCD23 indicates that integrins deliver to cells important signals initiated by soluble ligands without the requirement for interactions with RGD motifs in their common ligands. This mode of integrin signaling may not be restricted to alphavbeta5.

Therapeutic vaccination against cancer-associated antigens represents an attractive option for cancer therapy in view of its efficacy, the possibility of long-lasting immunity against the cancer, and safety profile. Nevertheless, it is now recognized that the same vaccination strategies used for prophylactic vaccinations against infectious diseases, cannot necessarily be used for therapeutic cancer vaccination. Cancer patients are usually immunosuppressed and most cancer-associated antigens are 'self-antigens', making it a significant challenge to vaccinate patients against a cancer-associated antigen. Various immunostimulation techniques are under investigation in an effort to bolster patients' immune systems and to overcome immune tolerance to self antigens. Strategies to stimulate antigen presentation, T-cell reactivity and innate immune activity are under investigation. Several clinical trials have been conducted to evaluate therapeutic cancer vaccines in patients, and attractive protocols, including those that combine the stimulation of specific T-cells and chemotherapy, or strategies to block immune regulation, are beginning to show some success. This feature review considers strategies for the development of effective therapeutic cancer vaccines, and highlights select vaccines that have already entered the clinic.

We observed that mast cells, as other cells expressing the CD40 ligand CD154, can trigger IgE synthesis in B cells in the presence of interleukin (IL)-4. Numerous complementary techniques can be used to follow the succession of molecular events leading to IgE synthesis. This chapter will illustrate how human B cells (naïve or memory) can be purified, stored, and cultivated in medium that is permissive for IgE synthesis and stimulated with IL-4 or IL-13 and CD40 activation, the latter being induced by soluble CD154, anti-CD40 antibodies, or CD154-expressing cells. All these molecules are expressed by mast cells. The quantification of the epsilon-sterile transcript synthesis by polymerase chain reaction or Northern blot, the epsilon excision circles produced during immunoglobulin heavy chain locus rearrangement by polymerase chain reaction, and the IgE production by enzyme-linked immunosorbent assay will be described.

Cancer vaccines - a dream or a reality? There is no doubt that a time will come when this new approach to cancer treatment will provide opportunities that will be both complementary and synergistic with existing treatments. Novelty is often linked to risk, and if there is a given medical field that desperately needs therapeutic improvement, cancer is it. Recent advances on the understanding of the functioning and manipulation of the immune system and on the host-tumour relationship, and on tumour escape, will soon pay off. However, the development of cancer vaccines is not an easy undertaking and the multitude of obstacles are presented and reviewed in this article. The cancer vaccine 'detractors' that are arguing negatively on the chances of success are, to this date, correct. Nevertheless, a parallel could be drawn from the monoclonal antibodies, which have suffered from a long and difficult history, to hold promise in man. Recent technological progress has once again demonstrated that one can eventually bypass the commonly accepted barriers, as there are now monoclonal-based products currently helping patients. The entire oncology community is eagerly awaiting the next chapter in the cancer vaccine story.

The aim of this study was to evaluate the presence and the role of the serum soluble costimulatory molecule CD28 in patients with systemic lupus erythematosus (SLE), primary Sjögren's syndrome (SS), and systemic sclerosis (SSc). Soluble CD28 concentration was determined by ELISA in 45 patients with SLE, 45 patients with primary SS, 30 patients with SSc, and 45 healthy subjects. We also evaluated CD28 mRNA expression by semiquantitative RT-PCR, and the biological activity of recombinant soluble CD28 on T lymphocyte activity. Concentrations of soluble CD28 were significantly higher in patients with SLE, primary SS and SSc than in healthy subjects. Soluble CD28 concentrations were higher in patients with systemic primary SS than in patients with glandular-limited primary SS. PCR analysis suggested that soluble CD28 resulted from the shedding of the membrane form. In vitro assay revealed that soluble CD28 inhibits the anti-CD3 mAb induced T cell proliferation. Soluble CD28, which modulates the proliferation of T lymphocytes, could be associated with disease severity in patients with autoimmune disease, especially primary SS. These results suggest that soluble CD28 could play an important role in the regulation of autoimmune diseases.

Murine models have shown that IL-18 has antiangiogenic and antitumor effects, but little is known about IL-18 production in human tumors. We investigated IL-18 expression in clinically localized prostate cancers by immunohistochemistry and showed that 75% of the prostate cancers studied (27/36 cases) presented with tumor cells producing IL-18. Prostate tumor cell lines PC-3, DU 145 and LNCaP synthesized the immature form of IL-18 (p24). IFN-gamma produced in prostate cancers induced caspase-1 mRNA and IL-18 secretion of tumor cell lines, which was inhibited by the cell-permeable Tyr-Val-Ala-Asp-aldehyde caspase-1 inhibitor (YVAD-CHO). Interestingly, IFN-alpha also induced IL-18 secretion of the poorly differentiated cell line PC-3. PC-3 and DU 145, but not the well-differentiated cell line LNCaP, expressed IL-18R alpha (IL-1Rrp) protein and transcripts for IL-18R beta (AcPL). Exogenous IL-18 increased mitochondrial activity of both cell lines evaluated by the tetrazolium (MTT) assay but did not influence their proliferation. This indicated that prostate tumor cells could secrete IL-18 in response to IFN-gamma in the tumor microenvironment and that IL-18 could act as a autocrine/paracrine factor for the tumor. In the cohort of patients studied, IL-18 expression in prostate cancers (with up to 10% of tumor cells stained) was associated with a favorable outcome and equally predictive as pathologic stage on multivariate analysis (log rank test, p = 0.02). Tumor IL-18 production is a novel physiopathologic feature of prostate cancer and appears to be a favorable event in the course of the disease. Modulation of IL-18 production by interferons could have a beneficial clinical effect, which deserves further investigation., (Copyright 2003 Wiley-Liss, Inc.)

Prevention of respiratory syncytial virus (RSV) disease will implicate neonatal priming. However, neonatal antigen exposure frequently results into Th2-like responses, some of which are critical for formalin-inactivated RSV (FI-RSV)-associated lung immunopathology. Neonatal immunization of mice may thus represent a more stringent model of RSV-enhanced pathology than adults. Indeed, after RSV challenge, lung cell infiltration, lymphocyte activation, and eosinophilia were higher following neonatal compared with adult FI-RSV priming of BALB/c mice. Unexpectedly, similar findings were obtained with Al(OH)(3)-adsorbed live RSV. In contrast, neonatal priming with BBG2Na, a recombinant RSV subunit vaccine candidate, formulated in either Al(OH)(3) or TiterMax (a Th1-driving adjuvant) resulted in predominant Th2- or Th1-like responses, respectively, but never elicited lung immunopathology post-challenge. Importantly, our data emphasize that the induction of Th2-like responses by RSV subunit vaccines do not necessarily imply lung immunopathology.

The protective efficacy of the influenza matrix protein epitope 58-66 (called M1), recognized in the context of human HLA-A2 molecules, was evaluated in a HLA-A2/K(b) transgenic mouse model of lethal influenza infection. Repeated subcutaneous immunizations with M1 increased the percentage of survival. This effect was mediated by T cells since protection was abolished following in vivo depletion of all T lymphocytes, CD8(+), or CD4(+) T cells. The survival correlated with the detection of memory CD8(+) splenocytes able to proliferate in vitro upon stimulation with M1 and to bind M1-loaded HLA-A2 dimers, as well as with M1-specific T cells in the lungs, which were directly cytotoxic to influenza-infected cells following influenza challenge. These results demonstrated for the first time that HLA-A2-restricted cytotoxic T cells specific for the major immunodominant influenza matrix epitope are protective against the infection. They encourage further in vivo evaluation of T cell epitopes recognized in the context of human MHC molecules.

Outer membrane protein (Omp)A is highly represented and conserved in the Enterobacteriaceae family. Using a recombinant OmpA from Klebsiella pneumoniae (kpOmpA), we have analysed the interaction between this bacterial cell wall protein and human Langerhans cells (LC), the antigen-presenting cells of the epidermis and mucosa. We showed that biotinylated kpOmpA binds to human LC freshly isolated from epidermis. kpOmpA up-regulated MHC class II, CD86 and CCR7 expression, enhanced migration in response to macrophage inflammatory protein-3beta (MIP-3beta) through a reconstituted basement membrane mimicking the prerequisite passage through the dermal-epidermal basement membrane on the way to lymph nodes. The allostimulatory function of kpOmpA-treated LC was more potent than that of untreated cells. Even though the proportion of LC which binds kpOmpA was shown to vary between individuals, our data indicate that kpOmpA binds to and activates LC, and suggest that recognition of OmpA by LC may be an initiating event in the antibacterial host response.

Human monocytes differentiate into dendritic cells (DCs) or macrophages according to the nature of environmental signals. Monocytes stimulated with granulocyte-macrophage colony-stimulating factor (GM-CSF) plus interleukin 4 (IL-4) yield DCs. We tested here whether interferon-gamma (IFN-gamma), a potent activator of macrophages, may modulate monocyte differentiation. Addition of IFN-gamma to IL-4 plus GM-CSF-stimulated monocytes switches their differentiation from DCs to CD14(-)CD64(+) macrophages. IFN-gamma increases macrophage colony-stimulating factor (M-CSF) and IL-6 production by IL-4 plus GM-CSF-stimulated monocytes by acting at the transcriptional level and acts together with IL-4 to up-regulate M-CSF but not IL-6 production. IFN-gamma also increases M-CSF receptor internalization. Results from neutralizing experiments show that both M-CSF and IL-6 are involved in the ability of IFN-gamma to skew monocyte differentiation from DCs to macrophages. Finally, this effect of IFN-gamma is limited to early stages of differentiation. When added to immature DCs, IFN-gamma up-regulates IL-6 but not M-CSF production and does not convert them to macrophages, even in the presence of exogenous M-CSF. In conclusion, IFN-gamma shifts monocyte differentiation to macrophages rather than DCs through autocrine M-CSF and IL-6 production. These data show that IFN-gamma controls the differentiation of antigen-presenting cells and thereby reveals a new mechanism by which IFN-gamma orchestrates the outcome of specific immune responses.

Outer membrane protein A (OmpA) is a class of proteins highly conserved among the Enterobacteriaceae family and throughout evolution. We have observed that antigen presenting cells (APCs) recognize and are activated by the recombinant OmpA from Klebsiella pneumoniae (KpOmpA). KpOmpA triggers cytokine production by macrophages and dendritic cells (DC), induces DC maturation and signals via Toll-like receptor 2. KpOmpA also interacts with endocytic receptor(s) expressed on DC and macrophages. Tumor antigens coupled to KpOmpA are taken up by APCs and gain access to the MHC class I pathway, triggering the initiation of protective anti-tumor cytotoxic responses in the absence of CD4 T cell help and adjuvant. Thus, OmpA appears as a new type of pathogen-associated molecular pattern (PAMP) usable as a vector in anti-infectious and therapeutic anti-tumor vaccines to elicit CTLs.

Respiratory syncytial virus (RSV) is responsible for severe low respiratory tract infections in young infants and the elderly. To investigate whether BBG2Na, a recombinant subunit vaccine comprising aa 130-230 of the RSV G protein, induced protective Abs in subjects over 60 years during phase II clinical trial, pre- and postimmunization sera of individuals immunized with BBG2Na or placebo were transferred into SCID mice before RSV challenge. These sera dose-dependently reduced lung RSV titers. However at some points of serial dilutions, postimmunization sera of BBG2Na-immunized subjects only were significantly more efficient than the corresponding preimmunization sera, in agreement with the induction of an increased Ab response against multiple epitopes on RSV-A G protein. Thus, BBG2Na is immunogenic in the elderly and confers passive protection in mice after serum transfer. To our knowledge, this is the first description of protective Abs induced by a subunit vaccine in human.

The protective mechanisms induced in the mouse upper respiratory tract (URT) after intraperitoneal immunization with G2Na, a recombinant respiratory syncytial virus (RSV) G protein fragment (amino acid residues 130 to 230), were investigated. This protection was recently shown to be mediated by CD4(+) T cells and to be critically dependent on the cysteines and amino acids 193 and 194 (H. Plotnicky-Gilquin, A. Robert, L. Chevalet, J.-F. Haeuw, A. Beck, J.-Y. Bonnefoy, C. Brandt, C.-A. Siegrist, T. N. Nguyen, and U. F. Power, J. Virol. 74:3455-3463, 2000). On G2Na, we identified a domain (amino acid residues 182 to 198) responsible for the T-helper-cell activity. This region coincided with a peptide designed AICK (residues 184 to 198) which includes the previously identified murine and human T-helper-cell epitope on the native G protein (P. W. Tebbey, M. Hagen, and G. E. Hancock, J. Exp. Med. 188:1967-1972, 1998). Immunization with AICK, in alum or complete Freund's adjuvant, significantly reduced nasal RSV titers in normal BALB/c mice. However, although lung protection was induced, in contrast to the case with live RSV, neither AICK nor G2Na was able to prevent nasal infection in gamma interferon (IFN-gamma)-knockout mice. Anti-IFN-gamma neutralizing antibodies partially inhibited URT protection after administration to G2Na-immunized BALB/c mice. Furthermore, while purified CD4(+) T cells from BALB/c mice immunized with G2Na or AICK significantly reduced lung and nasal infection of naive recipient mice after adoptive transfer, the cells from IFN-gamma-knockout mice had no effect. Together, these results demonstrated for the first time that the T-helper-cell epitope of RSV G protein induces URT protection in mice after parenteral immunization through a Th1-type, IFN-gamma-dependent mechanism.

Human respiratory syncytial virus (hRSV) is one of the most common causes of respiratory infection in infants and the elderly. Previous attempts to vaccinate children against RSV failed and the induction of an aberrant Th2-type immune response was shown to induce severe to fatal pulmonary disease characterised in part by eosinophilia. BBG2Na is a promising human RSV subunit vaccine candidate which successfully passed phase II clinical trials in adults in association with Adju-Phos((R)). However, this formulation is not the most suitable for use in children since aluminium salts are known to induce a Th2-based immune response. In this study, we describe a potent and safe adjuvant formulation for BBG2Na in dimethyldioctadecylammonium bromide (DDA) that induces a mixed Th1/Th2 immune response in BALB/c mice. Furthermore, BBG2Na showed the same protective efficacy against RSV challenge when formulated either in DDA or in alum in mice and cotton rats.

Background: Nuclear factor kappa B (NF-kappaB) is a ubiquitously expressed transcription factor that regulates cytokine and immunoglobulin (Ig) gene expression. In most cell types, the inactive p50/p65 NF-kappaB heterodimer is located in the cytoplasm, complexed to its IkappaB inhibitory unit. Stimulation of cells by various reagents such as bacterial endotoxin or cytokines leads to a dissociation of NF-kappaB from IkappaB and a rapid translocation of free NF-kappaB to the nucleus. The aim of this article is to define optimal conditions for the measurement of NF-kappaB translocation by both confocal microscopy and flow cytometry., Methods: Four commercial anti-NF-kappaB antibodies were evaluated by confocal microscopy, after using two methods of fixation and permeabilization of the cells. These antibodies were examined further by flow cytometry on purified nuclei., Results: Paraformaldehyde-methanol treatment of dendritic cells is a good combination to visualize NF-kappaB translocation by confocal microscopy. Three of the four antibodies tested gave good results on nonactivated and on lipopolysaccharide (LPS)-activated dendritic cells. The measurement of NF-kappaB translocation by flow cytometry on purified nuclei is a quick and sensitive method. Only one of the four evaluated antibodies showed a significant difference between nonactivated and activated cells. CONCLUSIONS; Microscopy and flow cytometry are quick and reproducible methods to measure NF-kappaB translocation and can be adapted to identify new molecules that activate dendritic cells., (Copyright 2002 Wiley-Liss, Inc.)

Polysaccharides (PSs) derived from Streptococcus pneumoniae include more than 90 serotypes and differ greatly in their immunogenicity. In addition, immunization with PSs does not induce high affinity antibody production and no memory B-cells are generated. Coupling PSs to carrier proteins has been reported to induce B-cell maturation and to install a B-cell memory. As an alternative carrier protein, the outer membrane protein A (OmpA) derived from Klebsiella pneumoniae has been coupled to various PSs. We evaluated the immunogenicity of two PS conjugates, using PS derived from S. pneumoniae types 14 and 19. In this report, we show that anti-PS IgG responses are generated after the conjugation of PSs to P40. In addition, the humoral response generated is able to protect mice from a bacterial challenge. Our results indicate that P40 could be included in the development of new PS conjugate vaccines.

We have previously identified a mAb that binds to a molecule expressed preferentially on the surface of cycling thymocytes. In this study the molecule recognized by this mAb has been identified in the mouse as CD147 (basigin) by expression cloning. We show that CD147 expression correlates with cycling of immature thymocytes even in the absence of TCRbeta selection and that ligation of this molecule on immature fetal thymocytes inhibits their further development into mature T cells.

The heterodimeric cytokine composed of the soluble ciliary neurotrophic factor receptor (sCNTFR) and the IL-6 family member cardiotrophin-like cytokine (CLC) was recently identified as a new ligand for gp130-leukemia inhibitory factor receptor (LIFR) complex [Plun-Favreau, H., Elson, G., Chabbert, M., Froger, J., deLapeyriere, O., Lelievre, E., Guillet, C., Hermann, J., Gauchat, J. F., Gascan, H. & Chevalier, S. (2001) EMBO J. 20, 1692-1703]. This heterodimer shows overlapping biological properties with LIF. Although CLC contains a putative signal peptide and therefore should enter into the classical secretory pathway, the protein has been shown to be retained within transfected mammalian cells, unless coexpressed with either sCNTFR or cytokine like factor (CLF) [Elson, G. C., Lelievre, E., Guillet, C., Chevalier, S., Plun-Favreau, H., Froger, J., Suard, I., de Coignac, A. B., Delneste, Y., Bonnefoy, J. Y., Gauchat, J. F. & Gascan, H. (2000) Nat. Neurosci. 3, 867-872]. In the present study, we demonstrate that a fusion protein comprising CLC covalently coupled through a glycine/serine linker to sCNTFR (CC-FP) is efficiently secreted from transfected mammalian cells. CC-FP shows enhanced activities in respect to the CLC/sCNTFR native complex, on a number of cells expressing gp130 and LIFR on their surface. In addition, CC-FP is able to compete with CNTF for cell binding, indicating that both cytokines share binding epitope(s) expressed by their receptor complex. Analysis of the downstream signaling events revealed the recruitment by CC-FP of the signal transducer and activator of transcription (STAT)-3, Akt and mitogen-activated protein (MAP) kinase pathways. The monomeric bioactive CLC/sCNTFR fusion protein is therefore a powerful tool to study the biological role of the recently described cytokine CLC.

A novel recombinant respiratory syncytial virus (RSV) subunit vaccine, designated BBG2Na, was administered to 108 healthy adults randomly assigned to receive 10, 100, or 300 microg of BBG2Na in aluminum phosphate or saline placebo. Each subject received 1, 2, or 3 intramuscular injections of the assigned dose at monthly intervals. Local and systemic reactions were mild, and no evidence of harmful properties of BBG2Na was reported. The highest ELISA and virus-neutralizing (VN) antibody responses were evident in the 100- and 300-microg groups; second or third injections provided no significant boosts against RSV-derived antigens. BBG2Na induced > or 2-fold and > or =4-fold increases in G2Na-specific ELISA units in up to 100% and 57% of subjects, respectively; corresponding RSV-A-specific responses were 89% and 67%. Furthermore, up to 71% of subjects had > or =2-fold VN titer increases. Antibody responses to 2 murine lung protective epitopes were also highly boosted after vaccination. Therefore, BBG2Na is safe, well tolerated, and highly immunogenic in RSV-seropositive adults.

A BALB/c mouse model of enhanced pulmonary pathology following vaccination with formalin-inactivated alum-adsorbed respiratory syncytial virus (FI-RSV) and live RSV challenge was used to determine the type and kinetics of histopathologic lesions induced and chemokine gene expression profiles in lung tissues. These data were compared and contrasted with data generated following primary and/or secondary RSV infection or RSV challenge following vaccination with a promising subunit vaccine, BBG2Na. Severe peribronchiolitis and perivascularitis coupled with alveolitis and interstitial inflammation were the hallmarks of lesions in the lungs of FI-RSV-primed mice, with peak histopathology evident on days 5 and 9. In contrast, primary RSV infection resulted in no discernible lesions, while challenge of RSV-primed mice resulted in rare but mild peribronchiolitis and perivascularitis, with no evidence of alveolitis or interstitial inflammation. Importantly, mice vaccinated with a broad dose range (20 to 0.02 microg) of a clinical formulation of BBG2Na in aluminium phosphate demonstrated histopathology similar to that observed in secondary RSV infection. At the molecular level, FI-RSV priming was characterized by a rapid and strong up-regulation of eotaxin and monocyte chemotactic protein 3 (MCP-3) relative gene expression (potent lymphocyte and eosinophil chemoattractants) that was sustained through late time points, early but intermittent up-regulation of GRO/melanoma growth stimulatory activity gene and inducible protein 10 gene expression, while macrophage inflammatory protein 2 (MIP-2) and especially MCP-1 were up-regulated only at late time points. By comparison, primary RSV infection or BBG2Na priming resulted in considerably lower eotaxin and MCP-3 gene expression increases postchallenge, while expression of lymphocyte or monocyte chemoattractant chemokine genes (MIP-1beta, MCP-1, and MIP-2) were of higher magnitude and kinetics at early, but not late, time points. Our combined histopathologic and chemokine gene expression data provide a basis for differentiating between aberrant FI-RSV-induced immune responses and normal responses associated with RSV infection in the mouse model. Consequently, our data suggest that BBG2Na may constitute a safe RSV subunit vaccine for use in seronegative infants.

Administration of vaccines by the nasal route has recently proven to be one of the most efficient ways for inducing both mucosal and systemic antibody responses in experimental animals. Our results demonstrate that P40, a well-defined outer membrane protein A from Klebsiella pneumoniae, is indeed a carrier molecule suitable for nasal immunization. Using fragments from the respiratory syncytial virus subgroup A (RSV-A) G protein as antigen models, it has been shown that P40 is able to induce both systemic and mucosal immunity when fused or coupled to a protein or a peptide and administered intranasally (i.n.) to naive or K. pneumoniae-primed mice. Confocal analyses of nasal mucosa-associated lymphoid tissue after i.n. instillation of P40 showed that this molecule is able to cross the nasal epithelium and target CD11c-positive cells likely to be murine dendritic cells or macrophages. More importantly, this targeting of antigen-presenting cells following i.n. immunization with a subunit of the RSV-A molecule in the absence of any mucosal adjuvant results in both upper and lower respiratory tract protection against RSV-A infection.

Allergic disorders are characterized by allergen-specific Th2-biased responses. Signals controlling Th2 cell polarization, especially those acting by polarizing dendritic cells (DC) into Th2-promoting DC (DC2), are not well known. Histamine, a mediator released by allergen-stimulated mast cells from allergic subjects, has been reported to activate human immature DC. We have therefore tested whether histamine affects DC polarization. We report here that histamine inhibits LPS-induced IL-12 production and polarizes uncommitted maturing DC into effector DC2. DC matured in the presence of histamine fail to produce IL-12 upon subsequent stimulation and prime Th2 responses, even in presence of IFN-gamma, a potent DC1-driving factor. All these effects are mediated through both H1 and H2 receptors. These data show that histamine is a potent DC2-polarizing factor and provide evidence for a novel mechanism that explains the initiation and maintenance of a predominant Th2 response in allergic disorders.

The decapeptide ELA (ELAGIGILTV), a Melan-A/MART-1 antigen immunodominant peptide analogue, is an interesting melanoma vaccine candidate alone or in combination with other tumour antigens. P40, the recombinant outer membrane protein A of Klebsiella pneumoniae (kpOmpA), was recently shown to target dendritic cells and to induce peptide-specific CTLs. Here we investigated the adjuvant role of P40 mixed or chemically conjugated to ELA. This compound is an N-terminal glutamic acid-containing peptide. However, it has been reported that the amino group and the gamma-carboxylic group of glutamic acids easily condense to form pyroglutamic derivatives. Usually, to overcome this stability problem, peptides of pharmaceutical interest were developed with a pyroglutamic acid instead of N-terminal glutamic acid, without loss of pharmacological properties. Unfortunately, the pyroglutamic acid derivative (PyrELA) as well as the N-terminal acetyl capped derivative (AcELA) failed to elicit CTL activity when mixed with P40 adjuvant protein. Despite the apparent minor modifications introduced by PyrELA and AcELA, these two derivatives have probably lower affinity than ELA for the class I Major Histocompatibility Complex. Furthermore, this stability problem is worse in the case of clinical grade ELA, produced as an acetate salt, like most of the pharmaceutical grade peptides. We report here that the hydrochloride shows a higher stability than the acetate and may be suitable for use in man., (Copyright 2001 The International Association for Biologicals.)