In this proposal, we seek funds to update an existing MoFlo high-speed cell sorting system at the NYU Langone Medical Center to the more current MoFlo XDP system. The existing cell sorter was purchased in 2002 via the S10 funding mechanism and is operated and maintained by the OCS Cytometry core staff in the core facility. This existing "legacy" MoFlo cell sorter is a heavily utilized cell sorter in the core, with an average of 6 hours of use each workday. Since it has been publically announced that the vendor will discontinue parts and service for this instrument in December 2013, upgrading this system to the MoFlo XDP platform is a logical choice, as it will ensure continued availability of this versatile instrument to the NYULMC investigators. The upgrade to the more-current XDP model increases performance and flexibility of this platform, and can be accomplished for less than half the cost of a new cell sorter. The features of the XDP sorter allow increased flexibility in experimental design by immunologists, who have traditionally been the majority users of cell sorting, and will also facilitate the growing needs of cellular, developmental and neuro-biologists to sort rare populations of cells to study targets of gene activity and the developmental potential of stem cells and progenitor cells. Clearly this upgrade has a compelling cost to benefit ratio, and will benefit the existing user base. The new cell sorter will improve the effectiveness of ongoing projects carried out in laboratories of the [twelve] listed major users at the medical center campus, all supported by NIH funding. In addition, the instrument will be available to the entire NYU Medical Center community, and will enhance the research of many other groups. Furthermore, its availability will enhance our ability to attract accomplished immunologists and cancer biologists in the recruitment of senior and junior faculty. We believe that the availabilityof this powerful machine on our campus will elicit new exciting research projects from a variety of scientists working in the fields of cancer, immunology, and animal development.