title: Delayed-type hypersensitivity: activation of mast cells by antigen-specific T-cell factors initiates the cascade of cellular interactions.
abstract: In delayed-type hypersensitivity reactions sensitized T cells orchestrate a cascade of cellular interactions. Initiation of these responses depends on a newly recognized event, namely the release of vasoactive mediators fiom mast cells that are activated by antigen-specific T-cell-derivedfactors. Here Philip Askenase and Henk Van Loveren discuss how this event initiates a sequence of steps that lead to T-cell recruitment of effector cells; and how this event differs from activation of mast cells by IgE antibody. They also suggest that the conventional time-based separation of immediate and delayed hypersensitivity should be replaced by a classcation based on the type of antigen-specific lymphocyte - B or T-responsible for the effects of hypersensitivity.
authors.affiliation: Section of Clinical Immunology and Allergy, Department of Medicine, Yale University School of Medicine, New Haven, CT 06510, USA.
authors.forename: P W
authors.initials: PW
authors.lastname: Askenase
authors.affiliation: Department of Pathology, Rijksuniversiteit Utrecht, 3511 HX Utrecht, The Netherlands.
authors.forename: H
authors.initials: H
authors.lastname: Van Loverent