The purpose of this NCRR Shared Instrument Grant application is to secure funding to purchase a Reflection"""""""" high speed parallel cell sorter for the Flow Cytometry Core Facility (FCCF) at the University of Virginia, School of Medicine. The FCCF is a very heavily used core facility at the University of Virginia and provides flow cytometry related services on a fee for service basis to the University community in general and particularly to NIH funded investigators in the School of Medicine. The FCCF currently serves over 200 investigators from the laboratories of 95 PIs from 27 different departments. Forty two of these PIs use the FCCF for cell sorting. The FCCF has a single FACSVantage SE Turbo sorter with DIVA option, which is currently run at near full capacity and is the only cell sorter within 70 miles of UVA. The use of cell sorting services has steadily increased since reorganization of the FCCF in 2001 and has exploded over the past 2 years. Increased use of the FCCF is the result of educational programs instituted by the FCCF that have greatly increased the awareness of investigators about flow cytometry and cell sorting as well as new faculty hires in the School of Medicine. The current cell sorter is booked two to four weeks in advance, which presents a serious impediment to ongoing research projects that are dependant on cell sorting. The cell sorting service in the FCCF has been hampered by the relatively high cost of a new cell sorter, which has prevented the FCCF from expanding to meet the needs of the UVA community. Purchase and implementation of the new cell sorter will 1) allow the FCCF to meet current demand for cell sorting, 2) meet anticipated requirements for increased capacity in the near future, 3) provide back up capability when the current machine needs repairs and 4) increase services available to the UVA community by increasing the parameters available for sorting. ? ? ?