The primary goal of the Tumor Immunology section of the Surgery Branch is to develop new immune-based therapies to treat patients with cancer. The Antigen Discovery Core facility (previously named the Peptide Sequencing Core facility) was developed to assist Surgery Branch investigators in the identification of antigenic tumor associated epitopes and in raising tumor reactive T cell populations capable of targeting those epitopes for use in treatment oriented clinical trials. When this core began in 1994, there was great interest in the Surgery Branch in identifying MHC restricted epitopes from tumor associated antigens primarily for the purpose of developing synthetic peptide vaccines. As such, the primary core services provided early during its evolution were peptide synthesis and purification. However, the focus of the Tumor Immunology section of the Surgery Branch has significantly shifted since then, and investigators are now primarily interested in pursuing clinical trials in which patients are treated with adoptively transferred tumor reactive T lymphocytes. Multiple clinical protocols have been conducted in which patients with melanoma have been treated with adoptively transferred tumor infiltrating lymphocytes (TIL), and the objective response rates in those trials were often greater than 50%. However, using current techniques, tumor reactive TIL can only be consistently generated and expanded in vitro from patients with melanoma. Thus, new strategies are needed to extend adoptive cell transfer immunotherapies to patients with prevalent histologies such as breast, renal, colon, pancreatic, and lung cancers. In order to assist investigators in the Sugery Branch to achieve the goal of extending current adoptive cell transfer protocols, the primary focus of the Antigen Discovery core has likewise shifted to developing new means for raising tumor reactive T cells for treating patients who can not be treated with conventional TIL. One approach that has been adopted by the Surgery Branch has employed the use of reverse immunology. MHC restricted peptides from a candidate tumor associated antigen are used to stimulate lymphocytes from humans or HLA transgenic mice. T cell receptors (TCRs) are then isolated from tumor reactive T cell clones and genetically introduced into previously non-reactive human T lymphocytes to confer novel tumor reactivity. These cells can then be expanded in vitro and adoptively transferred into patients with tumors that express the candidate antigen. In order to assist Surgery Branch investigators interested in pursuing these types of clinical trials, the Antigen Discovery core has developed techniques involved in all aspects of reverse immunology. As the interest in the Surgery Branch has shifted from developing peptide vaccines to implementing new adoptive cell transfer protocols, the primary Antigen Targeting Core services provided have shifted from peptide synthesis to developing techniques for raising tumor reactive T lymphocytes in vitro and genetically manipulating human T lymphocytes in vitro to express tumor reactive T cell receptors (TCRs) and accessory molecules. The Antigen Targeting Core facility has the technical expertise to assist and/or provide services associated with each step of developing new tumor reactive T cell populations and identifying new tumor reactive TCRs as follows: Step 1: Identification of candidate tumor antigens and epitopes Step 2a. In vitro stimulation of human peripheral blood lymphocytes (PBLs) with tumor associated peptides Step 2b. Immunization of HLA transgenic mice with human tumor antigens and in vitro stimulation of lymph node cells or splenocytes Step 3. Evaluation of T cell function Step 4. Isolation of TCR alpha and beta chains from reactive clones Step 5. Electroporation of TCR alpha and beta chain RNAs into human T cells and functional evaluation Step 6. Cloning of reactive TCRs into retroviral vectors and transduction of human T lymphocytes Step 7. Modification of TCR alpha and beta chains to improve function Step 8. Generation of a stable packaging cell line and GMP grade retroviral product Step 9. Transduction and expansion of large numbers of T cells for patient treatment