Charlotte Hetzel

Peptide-Mediated Immunoregulation

Quantitative and qualitative characteristics of the signals received by a T cell determine whether receptor ligation results in cell activation, cell death, or the induction of antigen-specific non-responsiveness. Environmental factors such as the nature of costimulation, antigen-presenting cell type, peptide structure and cytokine levels also influence the differentiation of CD4+ helper T cells into functionally distinct subsets, which now appear pivotal in many immune-mediated disorders, including autoimmunity and allergy. Selective manipulation of the immune response, such as the functional inactivation or deviation of the cytokine secretion patterns of specific T cells, may be an effective strategy for immunotherapy.

Peptide-Mediated Regulation of Allergic Diseases

Allergic disorders such as asthma and atopic dermatitis are the result of inappropriate immune responses to environmental allergens, particularly those derived from house dust mites, pollens, animal dander, fungal spores, insect venom and certain foods. An estimated 10 to 20% of the population of developed countries suffer from allergies, resulting in significant impairment of their quality of life.1 The allergic response is characterized by an over production of specific IgE antibody and the activation and infiltration of eosinophils, basophils and mast cells which release a spectrum of inflammatory mediators.2 Traditional allergen immunotherapy, which involves a series of injections of allergen extract, has proved beneficial in a limited number of disorders, notably bee venom allergy and allergic rhinitis due to grass and tree pollens and ragweed.3 However, the mechanisms of immunotherapy are poorly understood and, particularly in the case of inhalant allergens, are of limited efficacy, with variable clinical outcomes.4 There remains a need for safe and effective strategies of allergy therapy and a clearer understanding of the mechanisms involved.