PROJECT SUMMARY/ABSTRACT The University of California at Davis (UCD) is a diverse educational institution recognized for excellence in medical, veterinary and agricultural research. In 2010, the UCD Flow Cytometry Shared Resource Laboratory (FCSR) received S10 program support (S10-RR-026825) to purchase a multi-laser, 18-color BD Biosciences Fortessa analytic flow cytometer. The Fortessa has supported UCD investigators for 12 years, primarily at the UCD Medical Center in Sacramento, across a wide range of multidisciplinary programs including the Schools of Medicine and Veterinary Medicine, NCI Comprehensive Cancer Center, the Stem Cell Program and its GMP facility. After years of high utilization, the 18-color Fortessa no longer meets the needs of the NIH-funded faculty it supports. The projects of the nine Major and four Minor Users in this proposal have evolved to now require 20- 30 color capability. The Fortessa is limited to 18-color detection and cannot be upgraded because its electronics preclude the option to add more detectors. Further, its component systems are aged and have become unreliable and offer poor performance compared to modern equipment. The BD Biosciences Symphony A5 30-color flow cytometer is requested to replace the Fortessa. The Symphony A5 is manufactured with fast and quiet electronics, sensitive optics, improved fluidics and offers expanded fluorescent detection capability and reagent selection flexibility. Moreover, the Symphony retains several of the most popular features of the highly utilized Fortessa, including rapid tube loading with the option to use the 96-well plate enabled high-throughput sampler, and the intuitive DIVA software acquisition control software that our users are accustomed to using and strongly prefer over other programs. The Symphony will be equipped with 5 lasers and 32 photodetectors which allow investigators to choose from a wide array of modern fluorescent probes and proteins, many of which offer significant improvements in the multicolor applications our users require. The Symphony will be housed in laboratory space that is dedicated by the School of Medicine’s Stem Cell Program for shared cytometry equipment access. The success of NIH supported biological research at UC Davis depends on the uninterrupted availability of a flexible, reliable, and modern cytometry equipment that will support biomedical breakthroughs. The Symphony will be housed in, managed and maintained by the Sacramento Flow Cytometry Shared Resource facility so that UCD investigators have access to advanced, multi-color instrumentation and flow cytometry expertise for years to come.