The overall long-term objective of the Administrative Core will be to provide scientific direction & oversight, project management and fiscal & administrative infrastructure to support all of the Projects and Cores within the Allergen Epitope Research and Validation Center. The goal of the Administrative Core is to optimally facilitate the scientific objectives and goals of the Center. The scientific objectives and goals of the Center are to use in vivo models (clinical and pre-clinical) to identify, enrich and characterize allergen-specific T cells in order to understand how their frequency and functional phenotype changes in response to an allergen-specific intervention. In Project 1, blood samples from two Phase II clinical trial of peptide immunotherapy (one historic and one prospective) will be subjected to allergen-specific enrichment of T cells using novel MHC Class II tetramer reagents. Tetramer+ T cells will be characterized for frequency, chemokine receptor expressoin, memory phenotype, cytokine production profiles and regulatory T cell frequency. In Project 2, blood, bone marrow and bronchoalveolar lavage samples will be obtained before and after segmental lung allergen challenge with cat allergen extract. Fel d 1 tetramers will be emioyed to enrich allergen-specific T cells from each compartment and these cells will be characterized as above.The Administrative Core will support these objectives through the following Specific Aims; Aim 1: to provide scientific direction, guidance and strategy for the Center through interaction between the Center Management Committee (CMC), the NIH Program Officers and the Scientific Advisory Panel (SAP), Aim 2: to provide (a) project management, (b) coordination of activities/information between projects and sites (3) general administrative support to the Center, Aim 3: to provide fiscal management within the Center (between the three sites) and between the Center and the NIH.