Yifan Li

Duke University, Durham, North Carolina, United States

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Publications (3)29.18 Total impact

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    ABSTRACT: IgE-mediated allergic reactions to cashews and other nuts can trigger life-threatening anaphylaxis. Proactive therapies to decrease reaction severity do not exist. We aimed to determine the efficacy of pepsin-digested cashew proteins used as immunotherapy in a murine model of cashew allergy. Mice were sensitized to cashew and then underwent challenges with digested or native cashew allergens to assess the allergenicity of the protein preparations. Using native or pepsinized cashew proteins, mice underwent oral or intraperitoneal sensitization protocols to determine the immunogenic properties of the protein preparations. Finally, cashew-sensitized mice underwent an immunotherapy protocol with native or pepsinized cashew proteins and subsequent provocation challenges. Pepsinized cashew proteins elicited weaker allergic reactions than native cashew proteins but importantly retained the ability to stimulate cellular proliferation and cytokine production. Mice sensitized with pepsinized proteins reacted on challenge with native allergens, demonstrating that pepsinized allergens retain immunogenicity in vivo. Immunotherapy with pepsinized cashew allergens significantly decreased allergic symptoms and body temperature decrease relative to placebo after challenge with native and pepsinized proteins. Immunologic changes were comparable after immunotherapy with native or pepsinized allergens: T(H)2-type cytokine secretion from splenocytes was decreased, whereas specific IgG(1) and IgG(2a) levels were increased. Pepsinized cashew proteins are effective in treating cashew allergy in mice and appear to work through the same mechanisms as native protein immunotherapy.
    No preview · Article · Jul 2012 · The Journal of allergy and clinical immunology
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    ABSTRACT: Allergic reactions to tree nuts are often severe and are outgrown in less than 10% of diagnosed patients. To determine whether treatment of underlying tree nut sensitization will prevent allergic reactions to cross-reacting tree nuts and to determine the effects of single-tree nut immunotherapy on true multi-tree nut sensitization. Cross-reactivity model: Cashew-sensitized mice underwent immunotherapy with cashew and were subsequently challenged with cashew and pistachio. Multisensitization model: Cashew plus walnut-sensitized mice were treated with cashew alone, walnut alone, or both cashew and walnut and then underwent challenges to cashew and walnut. Challenges were assessed on the basis of symptoms, changes in body temperature, and mouse mast cell protease-1 release. In the cross-reactivity model, cashew immunotherapy completely prevented allergic reactions on challenges with cashew or the cross-reactive pistachio. In the multisensitization model, mice with cashew plus walnut allergy were significantly protected from anaphylactic reactions on cashew challenge in both the cashew-alone and walnut-alone immunotherapy groups. Results from the walnut challenge demonstrated significantly decreased allergic responses in the walnut immunotherapy group, whereas mice in the cashew immunotherapy group experienced significantly lower symptoms. In the cross-reactivity model, immunotherapy effectively decreased IL-4 and IL-5 production and increased IL-12 relative to placebo while also inducing a 5-fold increase in specific IgG(1). Single-tree nut immunotherapy can effectively decrease allergic responses in both the cross-reactivity and multisensitization mouse models. Further studies are needed to determine which single-tree nut immunotherapies will be most effective for specific multi-tree nut allergy profiles.
    No preview · Article · Jan 2011 · The Journal of allergy and clinical immunology
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    ABSTRACT: Infantile Pompe disease progresses to a lethal cardiomyopathy in absence of effective treatment. Enzyme-replacement therapy (ERT) with recombinant human acid alpha-glucosidase (rhGAA) has been effective in most patients with Pompe disease, but efficacy was reduced by high-titer antibody responses. Immunomodulatory gene therapy with a low dose adeno-associated virus (AAV) vector (2 x 10(10) particles) containing a liver-specific regulatory cassette significantly lowered immunoglobin G (IgG), IgG1, and IgE antibodies to GAA in Pompe disease mice, when compared with mock-treated mice (P < 0.05). AAV-LSPhGAApA had the same effect on GAA-antibody production whether it was given prior to, following, or simultaneously with the initial GAA injection. Mice given AAV-LSPhGAApA had significantly less decrease in body temperature (P < 0.001) and lower anaphylactic scores (P < 0.01) following the GAA challenge. Mouse mast cell protease-1 (MMCP-1) followed the pattern associated with hypersensitivity reactions (P < 0.05). Regulatory T cells (Treg) were demonstrated to play a role in the tolerance induced by gene therapy as depletion of Treg led to an increase in GAA-specific IgG (P < 0.001). Treg depleted mice were challenged with GAA and had significantly stronger allergic reactions than mice given gene therapy without subsequent Treg depletion (temperature: P < 0.01; symptoms: P < 0.05). Ubiquitous GAA expression failed to prevent antibody formation. Thus, immunomodulatory gene therapy could provide adjunctive therapy in lysosomal storage disorders treated by enzyme replacement.
    Full-text · Article · Aug 2009 · Molecular Therapy