PROJECT SUMMARY/ABSTRACT In Phases I and II, the Center for Microbial Pathogenesis and Host Inflammatory Responses (CMPHIR) established and maintained a Research and Technical Advancement Core to fill experimental gaps in the resources available in institutional cores maintained by the UAMS College of Medicine. One of these was a Flow Cytometry Core, the overall focus of which was to allow UAMS investigators to characterize cellular populations in the context of various pathological conditions. However, this Flow Cytometry Core was not sufficient to meet the needs CMPHIR researchers, and for this reason the CMPHIR invested heavily in the existing Flow Cytometry Core to provide these researchers with the resources they needed to characterize the host response to infection at a cellular level, and to do so under BSL-2–compliant conditions. We accomplished this task, and in Phase III we propose to integrate these services under the common umbrella of this more comprehensive Flow Cytometry Core (Core C). The proposed Core C will be supported through a combination of CMPHIR funding and continued institutional support. Daily operations will be supervised by Dr. Jason S. Stumhofer, Director, who will work with 2 full-time technicians. These technicians will have the primary responsibility for operating instrumentation within Core C on behalf of CMPHIR and other UAMS investigators and, in consultation with Dr. Stumhofer, assisting these investigators in experimental design and data interpretation. To promote self-sustainability, most Core C instruments will be operated by these technicians on a fee-for-service basis. There will be some exceptions to allow the users themselves to utilize the equipment, thus making it accessible after hours; in these cases, cost recovery will be accomplished using a fee-for-access model. This will allow us to recover a significant proportion of the costs associated with Core C and ensure the ability to upgrade and maintain the equipment in this core as needed as we move forward into Phase III and beyond.