PROJECT SUMMARY/ABSTRACT The Ventana Discovery Ultra is an automated stainer for immunohistochemistry (IHC) and in situ hybridization (ISH). The Confocal Microscopy and Image Analysis Core (CMIAC) at the Tulane National Primate Center (TNPRC) has over 30 years of combined experience performing IHC and ISH in nonhuman primate (NHP) tissues. Over the years, IHC and ISH have become fundamental to NIH-funded research at the TNPRC and are widely used by both intramural and extramural investigators. IHC and ISH staining at the TNPRC is currently performed manually by technicians with years of experience. In recent years, the CMIAC has acquired digital pathology and computer-based analyses that allow for the sensitive detection and quantification of IHC and ISH staining. These technological advancements have led to a need for highly reproducible IHC and ISH staining not achievable with the current manual methods. To address this need, nine NIH-funded principal investigators with a total of $19M per year in NIH funding have requested to be major users of the proposed Ventana Discovery Ultra because of its ability to improve the rigor and reproducibility of their IHC and ISH data. The Ventana Discovery Ultra is capable of completing the entire staining process from baking through secondary antibody application, preventing the need for manual intervention at any stage of the process. Multiplex staining protocols that require multiple rounds of primary and secondary antibody staining can also be performed without manual intervention. The Ventana Discovery Ultra is uniquely designed for research, allowing customization of each step of the staining protocol. This is ideal for the development of novel staining protocols, a necessity in NHP research which often requires the optimization of antibodies primarily generated for use in other species (mouse and human). Further, the Ventana Discovery Ultra accepts antibodies, probes, and reagents from third-party vendors, another important feature for the continued use of our extensive catalog of NHP-validated antibodies. In addition, the Ventana Discovery Ultra is one of the few automated stainers capable of performing ISH with signal amplification (RNAScope, ACDbio), a new leading-edge staining technique that is rapidly gaining popularity. This state-of-the-art functionality is necessary to meet the anticipated needs of our users for years to come. The Ventana Discovery Ultra also comes equipped with 30 individual slide bays allowing for the simultaneous staining of 30 unique protocols. This increases efficiency, enhances turnaround time, and facilitates the completion of multiple service requests for a Core laboratory that accommodates 25 investigators on an annual basis.