Abstract 5187: VistaPlex immunofluorescence assay panels provide reliable deep spatial phenotyping for diverse immuno-oncology applications

Abstract Multiplex immunofluorescence (mIF) is a powerful tool that enables deep phenotyping of immune and cancer cells across a wide variety of tissue types. The initial effort and cost required to develop high-plex mIF panels is significant and poses a considerable hurdle for adoption of spatial biology. To streamline high-plex assay development, we developed a process for creating and validating multiplex antibody panels for use in immuno-oncology applications that leverage CellScape™, an automated end-to-end platform for Precise Spatial Multiplexing. Our multiplex assay development was a rigorous, multi-stage, iterative process to evaluate antibodies for suitability, specificity, and reproducibility. These assay panels are formulated as ready-to-use VistaPlex™ assay kits and are intended to enable rapid, reliable spatial phenotyping of key immune populations. To confirm the utility of VistaPlex, we deployed the Human FFPE Spatial Immune Profiling Panel to stain and image various FFPE tissue samples on the CellScape platform. With CellScape, tissues are mounted in enclosed fluidic chambers while on-instrument staining, imaging and signal erasure are conducted in iterative rounds. The panel presented here contains antibodies against 16 common biomarkers used in immune-oncology applications. Among these are CD3, CD4, CD8, CD20, and CD45 to detect cell lineages, PD-1 and PD-L1, to interrogate immune checkpoints, and markers that inform about cell state and activation. Spatial immune profiling data were obtained from human tonsil, colon, breast, and lung tissue samples. Deep immune phenotyping was performed using unsupervised clustering analysis and AI-assisted cluster labelling, and biomarker distributions were studied in the context of cellular neighborhoods and other proximity analyses. Overall, we identified more than 19 cell phenotypes with varying frequencies and spatial arrangements across tissue samples. Our data are robust and demonstrate that VistaPlex Assay kits for spatial profiling present an efficient and cost-effective solution for users that want to break into spatial biology. Citation Format: Arne Christians, Charles E. Jackson, Jannik Boog, Matthew H. Ingalls, Adam Northcutt, Kayla E. Cashion, Jonah Rauer, Karen Kwarta, J Spencer Schwarz, Oliver Braubach. VistaPlex immunofluorescence assay panels provide reliable deep spatial phenotyping for diverse immuno-oncology applications abstract. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts) ; 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84 (6Suppl): Abstract nr 5187.