The Center for Quantitative Cell Analysis of the Pennsylvania State University seeks funds to purchase a high-speed cell sorter. This center is one of the Shared Technology Facilities of the Huck Institute of the Life Sciences, providing services for the entire University Park campus. Nine major NIH supported researchers seek an instrument that will sort at least five times faster than the facility's existing sorter with an increased level of viability due to the speed of the sorting. This multiparameter instrument will also increase analytical proficiency by allowing more simultaneous analysis of multiple markers and increased sensitivity because of improved optical configuration. It will also have the capacity to perform CFP/YFP FRET applications. Presently we can only do this on our imaging systems. Three molecular toxicologists will sort hepatocytes for subsequent molecular analysis and signaling characteristics. Five immunologists in the user group will sort rare event populations (<1%), which is difficult with the current instrument (not enough recovered cells for the needed experiments). Applications include sorting of immune subsets involved in asthma, sorting of erythroid progenitors, sorting HIV clones and sorting T cell subsets involved in Irritable Bowel Disease. ? ?