Publications (5)20.14 Total impact
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Article: Treatment of colitis with a commensal gut bacterium engineered to secrete human TGF-β1 under the control of dietary xylan 1.
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ABSTRACT: While cytokine therapy and the use of immunosuppressive cytokines such as transforming growth factor-β (TGF-β) offer great potential for the treatment of inflammatory bowel disease (IBD), issues concerning formulation, stability in vivo, delivery to target tissues, and potential toxicity need to be addressed. In consideration of these problems we engineered the human commensal bacterium Bacteroides ovatus for the controlled in situ delivery of TGF-β(1) and treatment of colitis. Sequence encoding the human tgf-β1 gene was cloned downstream of the xylanase promoter in the xylan operon of B. ovatus by homologous recombination. Resulting recombinants (BO-TGF) were tested for TGF-β production in the presence and absence of polysaccharide xylan in vitro and in vivo, and used to treat experimental murine colitis. Clinical and pathological scores were used to assess the effectiveness of therapy. Colonic inflammatory markers including inflammatory cytokine expression were assessed by colorimetric assay and real-time polymerase chain reaction (PCR). BO-TGF secreted high levels of biologically active dimeric TGF-β in vitro and in vivo in a xylan-controlled manner. Administration of xylan in drinking water to BO-TGF-treated mice resulted in a significant clinical improvement of colitis, accelerating healing of damaged colonic epithelium, reducing inflammatory cell infiltration, reducing expression of proinflammatory cytokines, and promoting production of mucin-rich goblet cells in colonic crypts. These beneficial effects are comparable and in most cases superior to that achieved by conventional steroid therapy. This novel drug delivery system has potential for the targeted and controlled delivery of TGF-β(1) and other immunotherapeutic agents for the long-term management of various bowel disorders.Inflammatory Bowel Diseases 09/2011; 17(9):1925-35. · 4.86 Impact Factor -
Article: Treatment of colitis with a commensal gut bacterium engineered to secrete human tgf‐β1 under the control of dietary xylan 1
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ABSTRACT: Background:While cytokine therapy and the use of immunosuppressive cytokines such as transforming growth factor-β (TGF-β) offer great potential for the treatment of inflammatory bowel disease (IBD), issues concerning formulation, stability in vivo, delivery to target tissues, and potential toxicity need to be addressed. In consideration of these problems we engineered the human commensal bacterium Bacteroidesovatus for the controlled in situ delivery of TGF-β1 and treatment of colitis.Methods:Sequence encoding the human tgf-β1 gene was cloned downstream of the xylanase promoter in the xylan operon of B.ovatus by homologous recombination. Resulting recombinants (BO-TGF) were tested for TGF-β production in the presence and absence of polysaccharide xylan in vitro and in vivo, and used to treat experimental murine colitis. Clinical and pathological scores were used to assess the effectiveness of therapy. Colonic inflammatory markers including inflammatory cytokine expression were assessed by colorimetric assay and real-time polymerase chain reaction (PCR).Results:BO-TGF secreted high levels of biologically active dimeric TGF-β in vitro and in vivo in a xylan-controlled manner. Administration of xylan in drinking water to BO-TGF-treated mice resulted in a significant clinical improvement of colitis, accelerating healing of damaged colonic epithelium, reducing inflammatory cell infiltration, reducing expression of proinflammatory cytokines, and promoting production of mucin-rich goblet cells in colonic crypts. These beneficial effects are comparable and in most cases superior to that achieved by conventional steroid therapy.Conclusions:This novel drug delivery system has potential for the targeted and controlled delivery of TGF-β1 and other immunotherapeutic agents for the long-term management of various bowel disorders. (Inflamm Bowel Dis 2010;)Inflammatory Bowel Diseases 08/2011; 17(9):1925 - 1935. · 4.86 Impact Factor -
Article: An assessment of biological potency and molecular characteristics of different innovator and noninnovator interferon-beta products.
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ABSTRACT: Approved innovator products and their noninnovator "copy" versions are likely to vary in their quality, eg, physicochemical characteristics and biological activity, with important implications for clinical efficacy and safety. Therefore, it is important to study and thoroughly evaluate the noninnovator products in comparison with approved products at the preclinical and clinical stages. We have obtained 4 noninnovator interferon (IFN)-β-1a products currently marketed in Latin America and Iran and compared these with approved IFN-β-1a products (Avonex and Rebif) obtained from the same geographical regions with respect to biological potency, estimated by in vitro bioassays, and molecular characteristics, assessed by immunoblotting and high-performance liquid chromatography. In this article, we present our data showing that the noninnovator IFN-β-1a products can vary considerably in their biological potency. In addition, we showed that all IFN-β-1a products formulated with human serum albumin contained variable amounts of higher-molecular-weight aggregates of IFN-β-1a and adducts with human serum albumin, these being more prevalent in 2 noninnovator IFN-β-1a products where biological potency was reduced compared with approved IFN-β-1a products. Additionally, significant lot-to-lot variability was observed for one of the noninnovator products. Taken together, the results of this study highlight the need for not only thorough in vitro characterization, but also preclinical and clinical assessment to ensure patient safety and efficacy.Journal of interferon & cytokine research: the official journal of the International Society for Interferon and Cytokine Research 12/2010; 31(4):383-92. · 1.63 Impact Factor -
Article: "Cytokine storm" in the phase I trial of monoclonal antibody TGN1412: better understanding the causes to improve preclinical testing of immunotherapeutics.
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ABSTRACT: The CD28-specific mAb TGN1412 rapidly caused a life-threatening "cytokine storm" in all six healthy volunteers in the Phase I clinical trial of this superagonist, signaling a failure of preclinical safety testing. We report novel in vitro procedures in which TGN1412, immobilized in various ways, is presented to human white blood cells in a manner that stimulates the striking release of cytokines and profound lymphocyte proliferation that occurred in vivo in humans. The novel procedures would have predicted the toxicity of this superagonist and are now being applied to emerging immunotherapeutics and to other therapeutics that have the potential to act upon the immune system. Data from these novel procedures, along with data from in vitro and in vivo studies in nonhuman primates, suggest that the dose of TGN1412 given to human volunteers was close to the maximum immunostimulatory dose and that TGN1412 is not a superagonist in nonhuman primates.The Journal of Immunology 10/2007; 179(5):3325-31. · 5.79 Impact Factor -
Article: Biological activity of interleukins-28 and -29: comparison with type I interferons.
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ABSTRACT: Despite binding to receptors distinct from those of type I interferons (IFNs), human interleukins-28A, -28B and -29 (IL-28A, IL-28B and IL-29; alternatively named IFN lambda-2 {IFN-lambda2}, IFN-lambda3 and IFN-lambda1, respectively, or collectively, type III IFNs), a small family of three structurally-related cytokines, are, like IFNs, known to induce antiviral activity. To further biologically characterize IL-28A and IL-29, we compared their activities with those of IFNs in a range of human cell lines. We found that they induced antiviral activity in fewer cell lines and more weakly than IFNs; also IL-28A was less active than IL-29. Additionally, we showed IL-28A and IL-29 induced reporter genes--protein MxA promoter linked to luciferase, or interferon stimulated response element (ISRE) linked to secreted alkaline phosphatase (SEAP)--more weakly than IFN. Antiproliferative activity was induced by IFNs in most cell lines, but only in one human glioblastoma cell line, LN319, was dose-dependent IL-29-growth inhibition demonstrable. Polymerase chain reaction (PCR) quantification of messenger (m) RNA of IL-28/29 receptor subunits, IL-28Ralpha and IL-10Rbeta, indicated variable expression levels; although their expression was highest in the responsive LN319 cell line, lower but significant expression of both mRNAs was found in relatively unresponsive cell lines. In conclusion, we found IL-28A and IL-29 act similarly to IFNs, but are less effective generally and have activity in a more limited range of cell lines.Cytokine 08/2005; 31(2):109-18. · 3.02 Impact Factor
