Our overall goal is to develop a new pipeline for antigen-based rapid diagnostic testing for screening FCoV infected cats. To achieve this, we propose to ‘reduce to practice’ a pair of spike protein-specific monoclonal antibodies (mAb) previously generated at Cornell)—including a first-in-class Mab to FCoV-1 spike—and screen feline coronavirus-infected and FIP-suspect cats (along with negative controls) for the presence of FCoV-1 vsFCoV-2. We will utilize the sample collection procedures established in the Whittaker lab to obtain a range of clinical samples (i.e. ascites or pleural fluid, conjunctival swabs, and whole blood), as well as tissue homogenates from deceased animals. We will screen these samples via ELISA, cytology and western blot techniques. We will compare the novel mAbs to a) existing (non-discriminatory) commercial mAbs (i.e. 3-70) and b) molecular analyses such as PCR and sequencing). Additionally, we will obtain the sequence of the novel mAbs, clone these sequences into expression plasmids and establish their large-scale production in vitro, and epitope map the novel mAbs to ensure coverage of as wide a range of possible virus strains that circulate globally. Upon completion of the studies, we expect our data will allow further validation of the novel mAbs as a diagnostic test for FCoV/FIP.