Project Summary: This is an administrative supplement proposal in response to NIGMS Notice number (NOT- GM-21-029). The purpose of this supplement proposal is to replace an outdated confocal microscope in the Imaging Core with a state-of-the-art Leica Stellaris 5 confocal microscope to support and extend the goals of the Host-Pathogen COBRE program. Our existing 16-year old Zeiss 510 META confocal microscope, which reached its end of service life in 2016, is based on old technology and is beginning to experience repair issues. As a result, COBRE investigators are unable to undertake imaging approaches that are possible using the technology that exists in current state-of-the-art microscopes. Replacing this instrument with a Leica Stellaris 5 confocal microscope will ensure that investigators have the technology they require to support and advance their research goals. The overall goals of these projects are to understand the immunological processes and mechanisms that underly a range of host-pathogen interactions in diseases caused by viral, bacterial, and parasitic infections. All projects require high resolution, multichannel imaging of samples labeled with fluorochromes having excitation wavelengths ranging from 405 nm to 633 nm in fixed and live samples. Unlike the existing confocal microscope in the Imaging Core, which is effectively a 3-channel system with conventional PMT detectors, the Stellaris 5 confocal microscope is a prism-based four channel system, equipped with ultrasensitive Power HyD S detectors and offering an array of advanced imaging features including superresolution imaging. It will allow investigators to image samples labelled with four or more fluorescent labels, including dyes such as DAPI, which cannot be visualized using our existing instrument. The Stellaris 5 microscope will be integrated into our already functional Imaging Core in association with other imaging equipment and will take advantage of existing web-based scheduling, technical support, web-based data storage and sharing, system contract support, and a microscopic imaging service supported by telemicroscopy. Acquisition of this instrumentation will build institutionally on our very successful COBRE, INBRE, and DaCCoTA CTR programs. The Stellaris 5 confocal with superresolution and other advanced capabilities will advance biomedical science research capacity by Host-Pathogen COBRE investigators. It will also extend the research capacity of investigators affiliated with Epigenomics in Development and Disease COBRE, investigators affiliated with the DaCCoTA CTR, and other investigators in the UND SMHS, on the UND campus, and in the regional research community.