ABSTRACT This renewal application seeks continued support for years 45-50 of the Washington University Training Program in Immunology. This renewal application refines the training program to take opportunities to address emerging needs and challenges in training of predoctoral and postdoctoral trainees. Washington University School of Medicine (WUSM) has been a major center /magnet for both research and training in immunology over many decades. The Immunology community at WUSM has achieved a world-recognized status, including 5 members of the National Academy of Sciences. It is characterized by a collaborative atmosphere that has helped establish an excellent environment for training young Immunologists. This T32 training has been a central component within this community, and has developed a symbiotic relationship that benefits the trainees and mentors alike. In this renewal application, we have kept those parts that have historically worked exceptionally well, and have also sought to address what we see as emerging challenges in obtaining a training toward becoming a leader in immunology research. The needs we see are a result of the ever- increasing amount of information, which has gradually led to a significant challenge for young trainees to master, in the short time allotted before the pressures of independent research and discovery in mentor's lab become the paramount motivation. Further, this application addresses questions from past reviews and refines the distinction between activities of predoctoral and postdoctoral trainees supported by this T32 training program and other trainees of the larger graduate program in immunology at WUSM. In this renewal, we have seen this as a positive opportunity to revise the specific training provided by this T32, through our creation of a new curriculum specifically tailored to providing a structured environment that ensures the trainee to obtain a broad and in depth mastery of basic immunology. We are requesting the continuation of the 6 predoctoral and 4 postdoctoral trainee slots per year. This successful Training Program is thus producing the next generation of basic and clinician scientists, whom we expect will elucidate the intricacies and mechanisms of our immune system functions, and thereby help develop novel therapeutic strategies for multiple human diseases.