The Cellular Immunology Core is designed to receive and process samples from human subjects in order to evaluate cellular immune responses. Standard operating procedures have been put into place and validated in accordance with ICH Harmonised Tripartite Guidelines [1]. The laboratory itself is run in the spirit of Good Laboratory Practices as outlined by FDA regulations. The facility has appropriately trained research technicians, a quick retrieval system for samples and data. In addition annual reviews of standard operating procedures and employee records have been instituted. This core has supported a number of clinical trials and will be responsible for the cellular immunology in the clinical studies that are outlined in the program project, Project 2/ In addition this core will collaborate with Projects 1, 3 and 4 on the proposed primate studies. Briefly, the program project outlines a plan to investigate new HIV-1 DNA immunotherapy. Project 1 will utilize the SIV infected macaque model to study immunotherapy. Project 2 includes two proposed clinical studies. Project 3 will investigate immune reconstitution and a collaborative effort between Core B and Project 3 will investigate immune reconstitution using MHC class I and class II tetramers specific for humans as detained in this core and in Project 3. Project 4 and this core will collaborate and will investigate CTL escape mutants and the persistence of viral reservoirs. The Core is intimately involved with Project 1. The first clinical study will be a dose-escalating safety and immune responsiveness study of a new plasmid construct containing the gene for IL-15 expression. The second clinical study will assess of the safety and immunostimulatory effects of co-administering the IL-15 construct with the HIV vaccines. The Clinical Immunology Core will perform the following assays: ELISPOT analysis, intracellular staining for IFN-gamma and MHC class I tetramer binding analysis for the clinical studies. The cumulative set of data will provide a comprehensive view of the CD8 and CD4HIV-1 specific responses and how they are enhanced by the various immunotherapy regimens. In addition, the core will collaborate with project 1 for intracellular straining for IFN-gamma in the proposed primate studies. Finally Core B will collaborate with Project 3 on MHC class I and class II tetramers.