Abstract We are requesting funds to purchase a Miltyeni MACSima imaging system. These new technologies allow for researchers to apply single cell proteomic analysis to cells in their resident tissue environment. For our investigators in the aging, cancer, immunology, and neuroscience research fields, the ability to advance conventional imaging analyses to examine an order of magnitude more proteins would provide much deeper insight into their scientific questions. Automation provided by this instrument will also allow more efficient and rapid analysis of more samples. The advantages of this new technology include using conventional antibodies already in use by the investigators and easy to use instrumentation. The resultant data can then be analyzed using state-of-the-art single cell informatic approaches. For example, this instrumentation would allow aging researchers at the OKC VAMC to identify senescent cells in a tissue section, determine what type of cell they are and examine senescence associated secretory factor – all in the same tissue section. Additionally, flexibility with the type of samples, human/laboratory animal, fixed/fresh frozen should allow the greatest number of investigators to benefit from this instrumentation. Iterative immunohistochemical imaging is the result of advances in antibody reporter technology, imaging, and automated image analysis. This enables single cell proteomic studies heretofore no possible. Samples are collected according to existing methods but can then be probed much deeper than with conventional imaging. The specific MACSima technology was identified through a needs assessment and offers greater simplicity of use and less method optimization as compared to mass cytometry and nucleic acid barcoding approach. This MACSima enabling technology has wide application to studies at the Oklahoma City VA Center and will advance variety or research programs. A survey of all VA researchers at OKC VAMC showed a wide variety of researchers will utilize the system. This instrument will be used by eight major users, and two junior investigator minor users with VA career development and pilot funding. The projects that will be enhanced by this instrumentation represent a large number VA Merit and career scientist grants.