Nuestros investigadores

Pablo Sarobe Ugarriza

Publicaciones científicas más recientes (desde 2010)

Autores: Llopiz, Diana Isabel; Sarobe, Pablo, (Autor de correspondencia)
Revista: CLINICAL CANCER RESEARCH
ISSN 1078-0432  Vol. 25  Nº 16  2019  págs. 4871 - 4873
Induction of antitumor responses by vaccines requires strong immunogens. Heterologous viral prime/boost immunization with the BN-CV301 vaccine promotes activation of immune responses that provide a clinical benefit to patients with cancer. This viral platform may be used to harbor different antigens and prime tumor immunity potentially useful for combinatorial strategies.
Autores: MM Soldevilla; Helena Villanueva; Daniel Meraviglia-Crivelli; et al.
Revista: MOLECULAR THERAPY
ISSN 1525-0016  Vol. 27  Nº 11  2019  págs. 1878 - 1891
Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) blockade therapy is able to induce long-lasting antitumor responses in a fraction of cancer patients. Nonetheless, there is still room for improvement in the quest for new therapeutic combinations. ICOS costimulation has been underscored as a possible target to include with CTLA-4 blocking treatment. Herein, we describe an ICOS agonistic aptamer that potentiates T cell activation and induces stronger antitumor responses when locally injected at the tumor site in combination with anti-CTLA-4 antibody in different tumor models. Furthermore, ICOS agonistic aptamer was engineered as a bi-specific tumor-targeting aptamer to reach any disseminated tumor lesions after systemic injection. Treatment with the bi-specific aptamer in combination with CTLA-4 blockade showed strong antitumor immunity, even in a melanoma tumor model where CTLA-4 treatment alone did not display any significant therapeutic benefit. Thus, this work provides strong support for the development of combinatorial therapies involving anti-CTLA-4 blockade and ICOS agonist tumor-targeting agents.
Autores: Sarobe, Pablo; Fernando Corrales, (Autor de correspondencia)
Revista: GUT
ISSN 0017-5749  Vol. 68  Nº 11  2019  págs. 1913 - 1914
Autores: Diana Llopiz; Marta Ruiz; Lorea Villanueva; et al.
Revista: CANCER IMMUNOLOGY IMMUNOTHERAPY
ISSN 0340-7004  Vol. 68  Nº 3  2019  págs. 379 - 393
Autores: Llopiz, Diana Isabel; Ruiz, Marta; et al.
Revista: FRONTIERS IN IMMUNOLOGY
ISSN 1664-3224  Vol. 9  2018  págs. 1923
Understanding mechanisms associated to dendritic cell (DC) functions has allowed developing new antitumor therapeutic vaccination strategies. However, these vaccines have demonstrated limited clinical results. Although the low immunogenicity of tumor antigens used and the presence of tumor-associated suppressive factors may in part account for these results, intrinsic vaccine-related factors may also be involved. Vaccines modulate DC functions by inducing activating and inhibitory signals that determine ensuing T cell responses. In this mini review, we focus on IL-10, inhibitory cytokine induced in DC upon vaccination, which defines a suppressive cell subset, discussing its implications as a potential target in combined vaccination immunotherapies.
Autores: Aritz Lasarte-Cia; et al.
Revista: FRONTIERS IN IMMUNOLOGY
ISSN 1664-3224  Vol. 9  Nº JAN  2018  págs. Article number: 68
A complex network of interactions exists between the immune, the olfactory, and the central nervous system (CNS). Inhalation of different fragrances can affect immunological reactions in response to an antigen but also may have effects on the CNS and cognitive activity. We performed an exploratory study of the immunomodulatory ability of a series of compounds representing each of the 10 odor categories or clusters described previously. We evaluated the impact of each particular odor on the immune response after immunization with the model antigen ovalbumin in combination with the TLR3 agonist poly I:C. We found that some odors behave as immunostimulatory agents, whereas others might be considered as potential immunosuppressant odors. Interestingly, the immunomodulatory capacity was, in some cases, strain-specific. In particular, one of the fragrances, carvone, was found to be immunostimulatory in BALB/c mice and immunosuppressive in C57BL/6J mice, facilitating or impairing viral clearance, respectively, in a model of a viral infection with a recombinant adenovirus. Importantly, inhalation of the odor improved the memory capacity in BALB/c mice in a fear-conditioning test, while it impaired this same capacity in C57BL/6J mice. The improvement in memory capacity in BALB/c was associated with higher CD3+ T cell infiltration into the hippocampus and increased local expression of mRNA coding for IL-1ß, TNF-¿, and IL-6 cytokines. In contrast, the memory impairment in C57BL/6 was associated with a reduction in CD3 numbers and an increase in IFN-¿. These data suggest an association between the immunomodulatory capacity of smells and their impact on the cognitive functions of the animals. These results highlight the potential of studying odors as therapeutic agents for CNS-related diseases.
Autores: Llopiz, Diana Isabel; Ruiz, Marta; et al.
Revista: ONCOIMMUNOLOGY
ISSN 2162-4011  Vol. 7  Nº 4  2018  págs. Article: e1409321
Tumor infiltrating lymphocytes have been associated with a better prognostic and with higher response rates in patients treated with checkpoint inhibiting antibodies, suggesting that strategies promoting tumor inflammation may enhance the efficacy of these currently available therapies. Our aim was thus to develop a new vaccination platform based on cold-inducible RNA binding protein (CIRP), an endogenous TLR4 ligand generated during inflammatory processes, and characterize whether it was amenable to combination with checkpoint inhibitors. In vitro, CIRP induced dendritic cell activation, migration and enhanced presentation of CIRP-bound antigens to T-cells. Accordingly, antigen conjugation to CIRP conferred immunogenicity, dependent on immunostimulatory and antigen-targeting capacities of CIRP. When applied in a therapeutic setting, vaccination led to CD8-dependent tumor rejection in several tumor models. Moreover, immunogenicity of this vaccination platform was enhanced not only by combination with additional adjuvants, but also with antibodies blocking PD-1/PD-L1, CTLA-4 and IL-10, immunosuppressive molecules usually present in the tumor environment and also induced by the vaccine. Therefore, priming with a CIRP-based vaccine combined with immune checkpoint-inhibiting antibodies rejected established B16-OVA tumors. Finally, equivalent activation and T-cell stimulatory effects were observed when using CIRP in vitro with human cells, suggesting that CIRP-based vaccination strategies could be a valuable clinical tool to include in combinatorial immunotherapeutic strategies in cancer patients.
Autores: Gorraiz, Marta; Lasarte-Cía, A.; et al.
Revista: ONCOTARGET
ISSN 1949-2553  Vol. 8  Nº 42  2017  págs. 71709 - 71724
Although T regulatory cells (Treg) are essential for the prevention of autoimmune diseases, their immunoregulatory function restrains the induction of immune responses against cancer. Thus, development of inhibitors of FOXP3, a key transcription factor for the immunosuppressive activity of Treg, might give new therapeutic opportunities. In a previous work we identified a peptide (named P60) able to enter into the cells, bind to FOXP3, and impair Treg activity in vitro and in vivo. Here we show that P60 binds to the intermediate region of FOXP3 and inhibits its homodimerization as well as its interaction with the transcription factor AML1. Alanine-scanning of P60 revealed the relevance of each position on FOXP3 binding, homodimerization, association with AML1 and inhibition of Treg activity. Introduction of alanine at positions 2, 5 and 11 improved the activity of the original P60, whereas alanine mutations at positions 1, 7, 8, 9, 10 and 12 were detrimental. Multiple mutation experiments allowed us to identify peptides with higher FOXP3 binding affinity and stronger biological activity than the original P60. Head to tail macrocyclization of peptide P60-D2A-S5A improved Treg inhibition and enhanced anti-tumor activity of anti-PD1 antibodies in a model of hepatocellular carcinoma. Introduction of a D-aminoacid at position 2 augmented significantly microsomal stability while maintained FOXP3 binding capacity and Treg inhibition in vitro. In vivo, when combined with the cytotoxic T-cell epitope AH1, it induced protection against CT26 tumor implantation. This study provides important structure¿function relationships essential for further drug design to inhibit Treg cells in cancer.
Autores: Gato-Cañas, M. ; Zuazo, M.; Arasanz, H. ; et al.
Revista: CELL REPORTS
ISSN 2211-1247  Vol. 20  Nº 8  2017  págs. 1818 - 1829
PDL1 blockade produces remarkable clinical responses, thought to occur by T cell reactivation through prevention of PDL1-PD1 T cell inhibitory interactions. Here, we find that PDL1 cell-intrinsic signaling protects cancer cells from interferon (IFN) cytotoxicity and accelerates tumor progression. PDL1 inhibited IFN signal transduction through a conserved class of sequence motifs that mediate crosstalk with IFN signaling. Abrogation of PDL1 expression or antibody-mediated PDL1 blockade strongly sensitized cancer cells to IFN cytotoxicity through a STAT3/caspase-7-dependent pathway. Moreover, somatic mutations found in human carcinomas within these PDL1 sequence motifs disrupted motif regulation, resulting in PDL1 molecules with enhanced protective activities from type I and type II IFN cytotoxicity. Overall, our results reveal a mode of action of PDL1 in cancer cells as a first line of defense against IFN cytotoxicity.
Autores: Llopiz, Diana Isabel; Infante, S.; et al.
Revista: ONCOTARGET
ISSN 1949-2553  Vol. 8  Nº 2  2017  págs. 2659 - 2671
Vaccination induces immunostimulatory signals that are often accompanied by regulatory mechanisms such as IL-10, which control T-cell activation and inhibit vaccine-dependent antitumor therapeutic effect. Here we characterized IL10-producing cells in different tumor models treated with therapeutic vaccines. Although several cell subsets produced IL-10 irrespective of treatment, an early vaccine-dependent induction of IL-10 was detected in dendritic cells (DC). IL-10 production defined a DC population characterized by a poorly mature phenotype, lower expression of T-cell stimulating molecules and upregulation of PD-L1. These IL-10(+) DC showed impaired in vitro T-cell stimulatory capacity, which was rescued by incubation with IL-10R and PD-L1-inhibiting antibodies. In vivo IL-10 blockade during vaccination decreased the proportion of IL-10(+) DC and improved their maturation, without modifying PD-L1 expression. Similarly, PD-L1 blockade did not affect IL-10 expression. Interestingly, vaccination combined with simultaneous blockade of IL-10 and PD-L1 induced stronger immune responses, resulting in a higher therapeutic efficacy in tumor-bearing mice. These results show that vaccine-induced immunoregulatory IL-10(+) DC impair priming of antitumor immunity, suggesting that therapeutic vaccination protocols may benefit from combined targeting of inhibitory molecules expressed by this DC subset.
Autores: Fernandez-Poma, S. M.; Salas, Diego; et al.
Revista: CANCER RESEARCH
ISSN 0008-5472  Vol. 77  Nº 13  2017  págs. 3672 - 3684
Recent studies have found that tumor-infiltrating lymphocytes (TIL) expressing PD-1 can recognize autologous tumor cells, suggesting that cells derived from PD-1(+) TILs can be used in adoptive T-cell therapy (ACT). However, no study thus far has evaluated the antitumor activity of PD-1-selected TILs in vivo. In two mouse models of solid tumors, we show that PD-1 allows identification and isolationof tumor-specific TILs without previous knowledge of their antigen specificities. Importantly, despite the high proportion of tumor-reactive T cells present in bulk CD8 TILs before expansion, only T-cell products derived fromsorted PD-1(+), but not from PD-1(-) or bulk CD8 TILs, specifically recognized tumor cells. The fold expansion of PD-1(+) CD8 TILs was 10 times lower than that of PD-1(-) cells, suggesting that outgrowth of PD-1(-) cells was the limiting factor in the tumor specificity of cells derived from bulk CD8 TILs. The highly differentiated state of PD-1(+) cells was likely the main cause hampering ex vivo expansion of this subset. Moreover, PD-1 precisely identified marrow-infiltrating, myeloma-specific T cells in a mouse model of multiple myeloma. In vivo, only cells expanded from PD-1(+) CD8 TILs contained tumor progression, and their efficacy was enhanced by PDL-1 blockade. Overall, our data provide a rationale for the use of PD-1-selected TILs in ACT. (C) 2017 AACR.
Autores: Llopiz, Diana Isabel; Ruiz, Marta; et al.
Revista: ONCOIMMUNOLOGY
ISSN 2162-402X  Vol. 5  Nº 2  2016  págs. e1075113
Blocking antibodies against immunosuppressive molecules have shown promising results in cancer patients. However, there are not enough data to define those conditions dictating treatment efficacy. In this scenario, IL-10 is a cytokine with controversial effects on tumor growth. Thus, our aim was to characterize in which setting IL-10 blockade may potentiate the beneficial effects of a therapeutic vaccine In the IL-10-expressing B16-OVA and TC-1 P3 (A15) tumor models, therapeutic vaccination with tumor antigens plus the TLR7 ligand Imiquimod increased IL-10 production. Although blockade of IL-10 signal with anti-IL-10R antibodies did not inhibit tumor growth, when combined with vaccination it enhanced tumor rejection, associated with stronger innate and adaptive immune responses. Interestingly, a similar enhancement on immune responses was observed after simultaneous vaccination and IL-10 blockade in naive mice. However, when using vaccines containing as adjuvants the TLR3 ligand poly(I:C) or anti-CD40 agonistic antibodies, despite tumor IL-10 expression, anti-IL-10R antibodies did not provide any beneficial effect on tumor growth and antitumor immune responses. Of note, as opposed to Imiquimod, vaccination with this type of adjuvants did not induce IL-10 and correlated with a lack of in vitro IL-10 production by dendritic cells (DC). Finally, in B16-OVA-bearing mice, blockade of IL-10 during therapeutic vaccination with a multiple adjuvant combination (MAC) with potent immuno
Autores: Zabaleta, Aintzane; Riezu-Boj, José Ignacio; Larrea, Esther; et al.
Revista: JOURNAL OF MEDICAL VIROLOGY
ISSN 0146-6615  Vol. 88  Nº 5  2016  págs. 843 - 851
Viral clearance during acute hepatitis C virus (HCV) infection is associated with the induction of potent antiviral T-cell responses. Since dendritic cells (DC) are essential in the activation of primary T-cell responses, gene expression was analyzed in DC from patients during acute HCV infection. By using microarrays, gene expression was compared in resting and activated peripheral blood plasmacytoid (pDC) and myeloid (mDC) DC from acute HCV resolving patients (AR) and from patients who become chronically infected (ANR), as well as in healthy individuals (CTRL) and chronically-infected patients (CHR). For pDC, a high number of upregulated genes was found in AR patients, irrespective of DC stimulation. However, for mDC, most evident differences were detected after DC stimulation, again corresponding to upregulated genes in AR patients. Divergent behavior of ANR was also observed when analyzing DC from CTRL and CHR, with ANR patients clustering again apart from these groups. These differences corresponded to metabolism-associated genes and genes belonging to pathways relevant for DC activation and cytokine responses. Thus, upregulation of relevant genes in DC during acute HCV infection may determine viral clearance, suggesting that dysfunctional DC may be responsible for the lack of efficient T-cell responses which lead to chronic HCV infection.
Autores: Flecken, T.; Sarobe, Pablo;
Revista: GUT
ISSN 0017-5749  Vol. 64  Nº 10  2015  págs. 1502 - 1503
Autores: Zabaleta, Aintzane; D'Avola, Delia; Llopiz, Diana Isabel; et al.
Revista: MOLECULAR THERAPY. METHODS & CLINICAL DEVELOPMENT
ISSN 2329-0501  Vol. 2  2015  págs. 15006
The lack of antiviral cellular immune responses in patients with chronic hepatitis C virus (HCV) infection suggests that T-cell vaccines may provide therapeutic benefit. Due to the central role that dendritic cells (DC) play in the activation of T-cell responses, our aim was to carry out a therapeutic vaccination clinical trial in HCV patients using DC. Five patients with chronic HCV infection were vaccinated with three doses of 5¿×¿10(6) or 10(7) autologous DC transduced with a recombinant adenovirus encoding NS3 using the adapter protein CFh40L, which facilitates DC transduction and maturation. No significant adverse effects were recorded after vaccination. Treatment caused no changes in serum liver enzymes nor in viral load. Vaccination induced weak but consistent expansion of T-cell responses against NS3 and adenoviral antigens. Patients' DC, as opposed to murine DC or DC from healthy subjects, secreted high IL-10 levels after transduction, inducing the activation of IL-10-producing T cells. IL-10 blockade during vaccine preparation restored its ability to stimulate anti-NS3 Th1 responses. Thus, vaccination with adenovirus-transduced DC is safe and induces weak antiviral immune responses. IL-10 associated with vaccine preparation may be partly responsible for these effects, suggesting that future vaccines should consider concomitant inhibition of this cytokine
Autores: Gorraiz, Marta; et al.
Revista: JOURNAL OF IMMUNOLOGY
ISSN 0022-1767  Vol. 195  Nº 7  2015  págs. 3180 - 3189
Regulatory T cell (Treg) activity is modulated by a cooperative complex between the transcription factor NFAT and FOXP3, a lineage specification factor for Tregs. FOXP3/NFAT interaction is required to repress expression of IL-2, upregulate expression of the Treg markers CTLA4 and CD25, and confer suppressor function to Tregs. However, FOXP3 is expressed transiently in conventional CD4+ T cells upon TCR stimulation and may lead to T cell hyporesponsiveness. We found that a short synthetic peptide able to inhibit FOXP3/NFAT interaction impaired suppressor activity of conventional Tregs in vitro. Specific inhibition of FOXP3/NFAT interaction with this inhibitory peptide revealed that FOXP3 downregulates NFAT-driven promoter activity of CD40L and IL-17. Inhibition of FOXP3/NFAT interaction upregulated CD40L expression on effector T cells and enhanced T cell proliferation and IL-2, IFN-¿, IL-6, or IL-17 production in response to TCR stimulation. The inhibitory peptide impaired effector T cell conversion into induced Tregs in the presence of TGF-ß. Moreover, in vivo peptide administration showed antitumor efficacy in mice bearing Hepa129 or TC1 tumor cells when combined with sorafenib or with an antitumor vaccine, respectively. Our results suggest that inhibition of NFAT/FOXP3 interaction might improve antitumor immunotherapies.
Autores: Sarobe, Pablo; Merino, J; et al.
Revista: TRANSPLANT IMMUNOLOGY
ISSN 0966-3274  Vol. 33  Nº 2  2015  págs. 110 - 116
Several studies have shown that some liver transplant recipients may tolerate immunosuppression withdrawal. Mechanisms and biomarkers of tolerance are not well known. Methods: Twenty-four LT patients with immunosuppression side-effects underwent progressive immunosuppression withdrawal. Peripheral lymphocyte populations and secretion of cytokines were analyzed at baseline and during withdrawal until tolerance (n = 15) or rejection (n = 9), as well as 3. months after tolerance achievement or rejection resolution (as follow-up). Immunological markers were compared among groups. Results: The percentages of CD3 + CD4 + cells progressively decreased in both groups. CD3 + CD8 + cells gradually increased in tolerant patients. B lymphocytes gradually decreased in tolerant and initially in non-tolerant patients, reverting at rejection. Regulatory T cells progressively increased until rejection in non-tolerants, decreasing to basal levels after renewing immunosuppression; no significant changes were found in tolerant patients. The percentages and absolute counts of natural killer cells significantly increased in both groups, being more evident in tolerant patients. The secretion of several cytokines was higher in non-tolerant patients when rejection was diagnosed. Conclusions: The greater increase of natural killer cells in tolerant patients suggests their potential role in the tolerance phenomenon
Autores: Iñarrairaegui, Mercedes; Páramo, José Antonio; et al.
Revista: LIVER INTERNATIONAL
ISSN 1478-3223  Vol. 35  Nº 5  2015  págs. 1590 - 96
BACKGROUND & AIMS: Radioembolization may rarely induce liver disease resulting in a syndrome that is similar to veno-occlusive disease complicating bone marrow transplantation where inflammation, endothelial cell activation and thrombosis are likely involved. We hypothesized that similar mechanisms could be implicated in radioembolization-induced liver disease (REILD). Moreover, lobar radioembolization may induce hypertrophy of the non-treated hemiliver most probably by inducing liver regeneration. METHODS: In patients with hepatocellular carcinoma, we prospectively studied serum levels of markers of liver regeneration, oxidative stress, pro-inflammatory pathways, endothelial activation and coagulation parameters over 2 months after radioembolization. RESULTS: Although REILD did not occur among 14 treated patients, a decrease in effective liver blood flow was observed. Radioembolization was followed by a persistent increase in pro-inflammatory (interleukin 6 and 8) and oxidative stress (malondyaldehide) markers, an induction of endothelial injury markers (vW factor and PAI-1) and an activation of the coagulation cascade (factor VIII, PAI-1, D-Dimer) as well as a significant increase in factors related to liver regeneration (FGF-19 and HGF). CONCLUSION: Radioembolization activates liver regeneration, produces oxidative stress, activates inflammatory cytokines and induces endothelial injury with partial activation of the coagulation cascade. These findings may have implicati
Autores: Larrea, Esther, (Autor de correspondencia); Riezu-Boj, José Ignacio; Aldabe, R; et al.
Revista: JOURNAL OF HEPATOLOGY (ONLINE)
ISSN 0168-8278  Vol. 60  Nº 3  2014  págs. 482 - 489
BACKGROUND & AIMS: Oncostatin M (OSM) is an inflammatory cytokine which interacts with a heterodimeric receptor formed by gp130 and either OSMRß or LIFR. Here we have analysed OSM and its receptors in livers with chronic hepatitis C (CHC) and studied the factors that regulate this system. METHODS: OSM, OSM receptors and OSM-target molecules were studied by immunohistochemistry and/or qPCR analysis in livers from CHC patients and controls. We determined the production of OSM by CD40L-stimulated antigen presenting cells (APC) and its biological effects on HuH7 cells containing HCV replicon (HuH7 Core-3'). RESULTS: OSM was upregulated in livers with CHC and its production was mapped to CD11c+ cells. OSM levels correlated directly with inflammatory activity and CD40L expression. In vitro studies showed that OSM is released by APC upon interaction with activated CD4+ T cells in a CD40L-dependent manner. Culture of HuH7 Core-3' cells with supernatant from CD40L-stimulated APC repressed HCV replication and induced IL-7 and IL-15R¿. These effects were dampened by antibodies blocking OSM or gp130 and by silencing OSMRß. In CHC livers OSMRß and LIFR were significantly downregulated and their values correlated with those of OSM-induced molecules. Experiments in HuH7 cells showed that impaired STAT3 signaling and exposure to TGFß1, two findings in CHC, are factors involved in repressing OSMRß and LIFR, respectively. CONCLUSIONS: OSM is a cytokine possessing vigorous antiviral and immunostimulatory properties which is released by APC upon interaction with CD40L present on activated CD4+ T cells. In livers with CHC, OSM is overexpressed but its biological activity appears to be hampered because of downregulation of its receptor subunits.
Autores: Larrea, Esther, (Autor de correspondencia); Riezu-Boj, José Ignacio; Aldabe, R; et al.
Revista: GUT
ISSN 0017-5749  Vol. 63  Nº 4  2014  págs. 665 - 673
Background IL-7 and IL-15 are produced by hepatocytes and are critical for the expansion and function of CD8 T cells. IL-15 needs to be presented by IL-15R¿ for efficient stimulation of CD8 T cells. Methods We analysed the hepatic levels of IL-7, IL-15, IL-15R¿ and interferon regulatory factors (IRF) in patients with chronic hepatitis C (CHC) (78% genotype 1) and the role of IRF1 and IRF2 on IL-7 and IL-15R¿ expression in Huh7 cells with or without hepatitis C virus (HCV) replicon. Results Hepatic expression of both IL-7 and IL-15R¿, but not of IL-15, was reduced in CHC. These patients exhibited decreased hepatic IRF2 messenger RNA levels and diminished IRF2 staining in hepatocyte nuclei. We found that IRF2 controls basal expression of both IL-7 and IL-15R¿ in Huh7 cells. IRF2, but not IRF1, is downregulated in cells with HCV genotype 1b replicon and this was accompanied by decreased expression of IL-7 and IL-15R¿, a defect reversed by overexpressing IRF2. Treating Huh7 cells with IFN¿ plus oncostatin M increased IL-7 and IL-15R¿ mRNA more intensely than either cytokine alone. This effect was mediated by strong upregulation of IRF1 triggered by the combined treatment. Induction of IRF1, IL-7 and IL-15R¿ by IFN¿ plus oncostatin M was dampened in replicon cells but the combination was more effective than either cytokine alone. Conclusions HCV genotype 1 infection downregulates IRF2 in hepatocytes attenuating hepatocellular expression of IL-7 and IL-15R¿. Our data reveal a new mechanism by which HCV abrogates specific T-cell responses and point to a novel therapeutic approach to stimulate anti-HCV immunity.
Autores:  et al.
Revista: BIOMED RESEARCH INTERNATIONAL
ISSN 2314-6133  2013  págs. 864720
The development of tools for efficient targeting of antigens to antigen presenting cells is of great importance for vaccine development. We have previously shown that fusion proteins containing antigens fused to the extra domain A from fibronectin (EDA), an endogenous TLR4 ligand, which targets antigens to TLR4-expressing dendritic cells (DC), are highly immunogenic. To facilitate the procedure of joining EDA to any antigen of choice, we have prepared the fusion protein EDAvidin by linking EDA to the N terminus of streptavidin, allowing its conjugation with biotinylated antigens. We found that EDAvidin, as streptavidin, forms tetramers and binds biotin or biotinylated proteins with a Kd ~ 2.6 × 10(-14) mol/L. EDAvidin favours the uptake of biotinylated green fluorescent protein by DC. Moreover, EDAvidin retains the proinflammatory properties of EDA, inducing NF- ¿ß by TLR4-expressing cells, as well as the production of TNF- ¿ by the human monocyte cell line THP1 and IL-12 by DC. More importantly, immunization of mice with EDAvidin conjugated with the biotinylated nonstructural NS3 protein from hepatitis C virus induces a strong anti-NS3 T cell immune response. These results open a new way to use the EDA-based delivery tool to target any antigen of choice to DC for vaccination against infectious diseases and cancer.
Autores: Llopiz, Diana Isabel; Ruiz, Marta; Bezunartea, J.; et al.
Revista: ONCOIMMUNOLOGY
ISSN 2162-402X  Vol. 2  Nº 12  2013  págs. UNSP e27009
Peptide vaccines derived from CD8(+) T-cell epitopes have shown variable efficacy in cancer patients. Thus, some peptide vaccines are capable of activating CD8(+) T-cell responses, even in the absence of CD4(+) T-cell epitopes or dendritic cell (DC)-activating adjuvants. However, the mechanisms underlying the clinical activity of these potent peptides are poorly understood. Using CT26 and ovalbumin-expressing B16 murine allograft tumor models, we found that the antitumor effect of helper cell-independent CD8 T-cell peptide vaccines is inhibited by the blockade of CD40 ligand (CD40L) in vivo. Furthermore, in vitro stimulation with antigenic peptides of cells derived from immunized mice induced the expression of CD40L on the surface of CD8(+) T cells and fostered DC maturation, an effect that was partially inhibited by CD40L-blocking antibodies. Interestingly, CD40L blockade also inhibited CD8(+) T-cell responses, even in the presence of fully mature DCs, suggesting a role for CD40L not only in promoting DC maturation but also in mediating CD8(+) T-cell co-stimulation. Importantly, these potent peptides share features with bona fide CD4 epitopes, since they foster responses against less immunogenic CD8(+) T-cell epitopes in a CD40L-dependent manner. The analysis of peptides used for the vaccination of cancer patients in clinical trials showed that these peptides also induce the expression of CD40L on the surface of CD8(+) T cells. Taken together, these results suggest that CD40L expression induced by potent CD8(+) T-cell epitopes can activate antitumor CD8(+) T-cell responses, potentially amplifying the immunological responses to less immunogenic CD8(+) T-cell epitopes and bypassing the requirement for CD4(+) helper T cells in vaccination protocols.
Autores: Sangro, Bruno; Gomez-Martin C; de la Mata M; et al.
Revista: JOURNAL OF HEPATOLOGY
ISSN 0168-8278  Vol. 59  Nº 1  2013  págs. 81-88
Background & Aims: Tremelimumab is a monoclonal antibody that blocks cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4), an inhibitory co-receptor that interferes with T cell activation and proliferation. The purpose of this pilot clinical trial was to test the antitumor and antiviral effect of tremelimumab in patients with hepatocellular carcinoma (HCC) and chronic hepatitis C virus (HCV) infection; and to study the safety of its administration to cirrhotic patients. Methods: Tremelimumab at a dose of 15 mg/kg IV every 90 days was administered until tumor progression or severe toxicity. Twenty patients were assessable for toxicity and viral response and 17 were assessable for tumor response. Most patients were in the advanced stage and 43% had an altered liver function (Child-Pugh class B). Results: A good safety profile was recorded and no patient needed steroids because of severe immune-mediated adverse events. Some patients had a transient albeit intense elevation of transaminases after the first dose, but not following subsequent cycles. Partial response rate was 17.6% and disease control rate was 76.4%. Time to progression was 6.48 months (95% CI 3.95-9.14). A significant drop in viral load was observed while new emerging variants of the hypervariable region 1 of HCV replaced the predominant variants present before therapy, particularly in those patients with a more prominent drop in viral load. This antiviral effect was associated with an enhanced specific anti-HCV immune response. Conclusions: Tremelimumab safety profile and antitumor and antiviral activity, in patients with advanced HCC developed on HCV-induced liver cirrhosis, support further investigation. (C) 2013 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.
Autores: Sarobe, Pablo; Merino, J; et al.
Revista: LIVER TRANSPLANTATION
ISSN 1527-6465  Vol. 19  Nº 9  2013  págs. 937 - 944
Recipients of liver transplantation (LT) may develop immunological tolerance. Factors predictive of tolerance are not clearly understood. Transplant recipients with normal liver function tests and without active viral hepatitis or autoimmune disease who presented with side effects of immunosuppression or a high risk of de novo malignancies were selected to participate in this prospective study. Twenty-four patients fulfilled the inclusion criteria and, therefore, underwent a gradual reduction of immunosuppression. Tolerance was defined as normal liver function tests after immunosuppression withdrawal. Basal clinical and immunological characteristics, including lymphocyte counts and subpopulations (T, B, natural killer, CD4+, CD8+, and regulatory T cells) and the phytohemagglutinin stimulation index (SI), were compared for tolerant and nontolerant patients. Fifteen of the 24 patients (62.5%) were tolerant at a median of 14 months (interquartile range¿=¿8.5-22.5 months) after complete immunosuppression withdrawal. Tolerant patients had a longer median interval between transplantation and inclusion in the study (156 for tolerant patients versus 71 months for nontolerant patients, P¿=¿0.003) and a lower median SI (7.49 for tolerant patients versus 41.73 for nontolerant patients, P¿=¿0.01). We identified 3 groups of patients with different probabilities of tolerance: in the first group (n¿=¿7 for an interval¿>¿10 years and an SI¿<¿20), 100% reached tolerance; in the second group (n¿=¿10 for an interval¿>¿10 years and an SI¿>¿20 or an interval¿<¿10 years and an SI¿<¿20), 60% reached tolerance; and in the third group (n¿=¿7 for an interval¿<¿10 years and an SI¿>¿20), 29% reached tolerance. In conclusion, a high proportion of select LT recipients can reach tolerance over the long term. Two simple basal variables¿the time from transplantation and the SI¿may help to identify these patients.
Autores: Sandra Hervas-Stubbs; Berasain, C; Golvano, J.; et al.
Revista: VACCINE
ISSN 0264-410X  Vol. 12  Nº 10  2012  págs. 867 - 871
This work shows that class II-linked humoral lack of response to an antigen can be overcome by joint immunization with the antigen and a T-helper cell determinant (TDh) well recognized by class II molecules of a non-responder individual. Thus, SJL/J mice (H-2s), which are non-responders to the S region of hepatitis B virus surface antigen (HBsAg), were rendered responders by joint immunization with a recombinant surface antigen, only composed of the S region, and a short synthetic TDh peptide well recognized by the H-2s restriction. By contrast, when this peptide is not recognized as TDh, as in B10M mice (H-2f restricted and also non-responders to the S region), no humoral response could be induced against the S region. These results have important implications for therapy and vaccination against hepatitis B virus as well as in enhancing the immunogenicity of other antigens.
Autores: Rudilla, F; Fayolle, C; Casares, N; et al.
Revista: VACCINE
ISSN 0264-410X  Vol. 30  Nº 18  2012  págs. 2848 - 2858
The complement system and Toll-like receptors (TLR) are key innate defense systems which might interact synergistically on dendritic cells (DC) to reinforce adaptive immunity. In a previous work, we found that the extra domain A from fibronectin EDA (an endogenous ligand for TLR4) can favour antigen delivery to DC and induce their maturation. Given the potential of anaphylatoxins to cause inflammation and activation of myeloid cells, we hypothesized that a fusion protein between EDA, and anaphylatoxins C3a, C4a or C5a together with an antigen might improve the immunogenicity of the antigen. Naked DNA immunization with a construct expressing the fusion protein between C5a, EDA and the cytotoxic T cell epitope SIINFEKL from ovalbumin, induced strong antigen specific T cell responses. The purified recombinant fusion protein EDA¿SIINFEKL¿C5a induced activation of dendritic cells, the production of proinflammatory cytokines/chemokines and stimulated antigen presenting cell migration and NK cell activation. As compared to EDA¿SIINFEKL, the fusion protein EDA¿SIINFEKL¿C5a did not induce the production of the immunosuppressive molecules IL-10, CCL17, CCL1, CXCL12 or XCL1 by DC. Moreover, EDA¿SIINFEKL¿C5a induced strong specific T cell responses in vivo and protected mice against E.G7-OVA tumor growth more efficiently than EDA¿SIINFEKL or SIINFEKL¿C5a recombinant proteins. Our results suggest that fusion proteins containing EDA, the anaphylatoxin C5a and the antigen may serve as a suitable strategy for the development of anti-tumor or anti-viral vaccines.
Autores: Berraondo, Pedro; et al.
Revista: INTERNATIONAL JOURNAL OF CANCER
ISSN 0020-7136  Vol. 131  Nº 3  2012  págs. 641 - 651
Cervical carcinoma is one of the most common cancers in women worldwide. It is well established that chronic infection of the genital tract by various mucosatropic human papillomavirus (HPV) types causes cervical cancer. Cellular immunity to E7 protein from HPV (HPVE7) has been associated with clinical and cytologic resolution of HPV-induced lesions. Thus, we decided to test if targeting of HPVE7 to dendritic cells using a fusion protein containing the extra domain A (EDA) from fibronectin, a natural ligand for TLR4, and HPVE7 (EDA-HPVE7) might be an efficient vaccine for the treatment of cervical carcinoma. We found that EDA-HPVE7 fusion protein was efficiently captured by bone marrow derived dendritic cells in vitro and induced their maturation, with the upregulation of maturation markers and the production of IL-12. Immunization of mice with EDA-HPVE7 fusion protein induced antitumor CD8+ T cell responses in the absence of additional adjuvants. Repeated intratumoral administration of EDA-HPVE7 in saline was able to cure established TC-1 tumors of 57 mm in diameter. More importantly, intravenous injection with EDA-HPVE7 in combination with the TLR ligand polyinosinic-polycytidylic acid (pIC), or with low doses of cyclophosphamide and the TLR9 ligand CpG-B complexed in cationic lipids, were able to eradicate large established TC-1 tumors (1.2 cm in diameter). Thus, therapeutic vaccination with EDA-HPVE7 fusion protein may be effective in the treatment of human cervical carcinoma.
Autores: Pereboev, A; Zabaleta, Aintzane; et al.
Revista: HEPATOLOGY
ISSN 0270-9139  Vol. 1  Nº 54  2011  págs. 28 - 37
Autores:  et al.
Revista: CANCER RESEARCH
ISSN 0008-5472  Vol. 71  Nº 3  2011  págs. 812 - 821
Autores: Riezu-Boj, José Ignacio; Larrea, Esther; Aldabe, R; et al.
Revista: JOURNAL OF HEPATOLOGY
ISSN 0168-8278  Vol. 54  Nº 3  2011  págs. 422 - 431
Autores: Llopiz, Diana Isabel; Riezu-Boj, José Ignacio; et al.
Revista: CANCER RESEARCH
ISSN 0008-5472  Vol. 71  Nº 9  2011  págs. 3214 - 3224
Autores: Ochoa, María del Carmen; Sandra Hervas-Stubbs; et al.
Revista: CANCER IMMUNOLOGY IMMUNOTHERAPY
ISSN 0340-7004  Vol. 60  Nº 5  2011  págs. 753 - 756
Autores: Alaniz, L; Rizzo, M; García, MG; et al.
Revista: CANCER IMMUNOLOGY IMMUNOTHERAPY
ISSN 0340-7004  Vol. 60  Nº 10  2011  págs. 1383 - 1395
Autores: Riezu-Boj, José Ignacio; et al.
Revista: CYTOKINE
ISSN 1043-4666  Vol. 53  Nº 3  2011  págs. 327 - 333
Autores: Riezu-Boj, José Ignacio; et al.
Revista: HEPATOLOGY
ISSN 0270-9139  Vol. 53  Nº 1  2011  págs. 23 - 31
Autores: Fayolle; Casares, N; et al.
Revista: VACCINE
ISSN 0264-410X  Vol. 28  Nº 44  2010  págs. 7146-7154
Staphylococcus epidermidis releases a complex of at least four peptides, termed phenol-soluble modulins (PSM), which stimulate macrophages to produce proinflammatory cytokines via activation of TLR2 signalling pathway. We demonstrated that covalent linkage of PSM peptides to an antigen facilitate its capture by dendritic cells and, in combination with different TLR ligands, can favour the in vivo induction of strong and persistent antigen-specific immune responses. Treatment of mice grafted with HPV16-E7-expressing tumor cells (TC-1)with poly(l: C) and a peptide containing alpha Mod linked to the H-2D(b)-restricted cytotoxic T-cell epitope E7(49-57) from HPV16-E7 protein allowed complete tumor regression in 100% of the animals. Surprisingly, this immunomodulatory property of modulin-derived peptides was TLR2 independent and partially dependent upon the EGF-receptor signalling pathway. Our results suggest that alpha or gamma modulin peptides may serve as a suitable antigen carrier for the development of anti-tumoral or anti-viral vaccines. (C) 2010 Elsevier Ltd. All rights reserved.
Autores:  et al.
Revista: VACCINE
ISSN 0264-410X  Vol. 28  Nº 32  2010  págs. 5323 - 5331
Autores: Casares, N; et al.
Revista: JOURNAL OF IMMUNOLOGY
ISSN 0022-1767  Vol. 185  Nº 9  2010  págs. 5150 - 5159
Immunosuppressive activity of regulatory T cells (Treg) may contribute to the progression of cancer or infectious diseases by preventing the induction of specific immune responses. Using a phage-displayed random peptide library, we identified a 15-mer synthetic peptide, P60, able to bind to forkhead/winged helix transcription factor 3 (FOXP3), a factor required for development and function of Treg. P60 enters the cells, inhibits FOXP3 nuclear translocation, and reduces its ability to suppress the transcription factors NF-¿B and NFAT. In vitro, P60 inhibited murine and human-derived Treg and improved effector T cell stimulation. P60 administration to newborn mice induced a lymphoproliferative autoimmune syndrome resembling the reported pathology in scurfy mice lacking functional Foxp3. However, P60 did not cause toxic effects in adult mice and, when given to BALB/c mice immunized with the cytotoxic T cell epitope AH1 from CT26 tumor cells, it induced protection against tumor implantation. Similarly, P60 improved the antiviral efficacy of a recombinant adenovirus expressing NS3 protein from hepatitis C virus. Functional inhibition of Treg by the FOXP3-inhibitory peptide P60 constitutes a strategy to enhance antitumor and antiviral immunotherapies.