The Multiple Species Tissue Array (MSTA) slides were designed to study protein expression patterns in different cells and tissues from multiple species. Tissue slices from three different species are mounted on each MSTA slide which can then be treated as a single histological slide for H&E staining, immunohistochemistry, or in situ hybridization. This format allows a rapid analysis of protein expression and localization across different species. MSTA slides can also be used to quickly determine the species reactivity of a given antibody.