A New Perspective in Spatial Proteomics Research: Application and Advantages of Recombinant Rabbit Monoclonal Antibodies in GeoMx® DSP Technology

I. Introduction

With the rapid advancement of spatial biology technologies, there is a growing need among researchers to understand the spatial distribution of protein expression and its functional significance within the tissue microenvironment. The GeoMx® Digital Spatial Profiler (DSP) platform, launched by NanoString in 2019, enables simultaneous, in situ, high-plex, and spatially resolved quantitative analysis of both proteins and RNA directly on intact tissue sections. Within this technological framework, Immunohistochemistry (IHC) antibodies are not only core reagents for traditional immunohistochemistry but also act as "molecular detectors" in DSP spatial proteomics research, whose quality directly impacts the accuracy and reproducibility of experiments.

This article will focus on the application of recombinant rabbit monoclonal antibodies within the GeoMx DSP platform, discussing their technical advantages, validation methods, and potential across various life science research fields.

II. GeoMx DSP Technology and the Principle of Spatial Proteomics

GeoMx DSP technology combines high-resolution tissue imaging with in situ oligonucleotide tagging. Its core principle involves using antibody probes conjugated with unique barcodes to identify target proteins in situ. Following target binding, oligonucleotide tags from user-selected Regions of Interest (ROI) or Areas of Illumination (AOI) are released via UV cleavage and collected for subsequent high-throughput sequencing, enabling quantitative and spatially resolved protein expression analysis.

The workflow primarily includes:

1.     Tissue Staining: Using IHC antibodies tagged with fluorescent labels (for morphology) and DSP barcodes (for quantification).

2.     Region Selection: Defining ROIs/AOIs based on morphological markers.

3.     Oligonucleotide Release and Collection: UV light cleaves and releases the barcode sequences from the selected areas for collection.

4.     Library Preparation and Sequencing: PCR amplification and Next-Generation Sequencing (NGS) to obtain spatial expression data.

 III. Key Requirements for DSP-Compatible Antibodies

To meet the high sensitivity and specificity demands of DSP technology, the antibodies used must fulfill the following six core requirements:

1.     High Specificity: Antibodies must be rigorously validated in in situ techniques like IHC/IF to ensure they recognize only the target antigen. Recombinant rabbit mAbs, with their broader immune repertoire and superior epitope recognition capabilities, are an ideal choice for DSP applications.

2.     No Cross-Reactivity: Within complex multiplex protein panels, antibodies must avoid cross-reactivity with other proteins or antibodies.

3.     High Affinity and Sensitivity: Especially critical for FFPE samples, antibodies must recognize epitopes exposed after formalin fixation and antigen retrieval, and maintain detectable signals even for low-abundance targets. Recombinant rabbit mAbs typically exhibit equilibrium dissociation constants (KD) in the picomolar range, significantly outperforming most murine antibodies.

4.     Low Aggregation Tendency: Antibodies must remain stable and avoid aggregation after oligonucleotide labeling, which could compromise signal quality.

5.     Compatibility with Oligonucleotide Labeling: Antibodies must be effectively conjugated to DSP barcodes without compromising their binding activity.

6.     Batch-to-Batch Consistency: Performance of antibodies post-labeling must be consistent across different batches to ensure experimental reproducibility.

IV. Validation of Starter Recombinant Rabbit mAbs in DSP Applications

Leveraging its proprietary recombinant rabbit mAb platform, Starter Bio has developed a series of high-performance antibodies suitable for the GeoMx DSP, systematically validated across multiple species and tissue types. Below are application examples for some representative antibodies:

These antibodies not only perform excellently in traditional IHC but also maintain high binding activity and low background noise after DSP barcode conjugation, making them suitable for various research areas including cancer immunology, neuroscience, and developmental biology.

V. Research and Industrial Application Prospects

·       Tumor Microenvironment Studies: Simultaneous analysis of dozens of protein markers reveals cellular interactions and heterogeneity.

·       Immune Cell Localization Analysis: Markers like CD3 and CD163 help resolve the distribution of immune cells within tumor tissues.

·       Drug Development & Biomarker Discovery: Evaluating the impact of drugs on spatial protein expression in pre-clinical models.

·       Neuroscience: Investigating brain region-specific protein expression and its relationship to neurological disorders.

VI. Conclusion

High-quality, highly specific IHC antibodies are a crucial technological foundation driving the advancement of spatial proteomics. Starter's portfolio of recombinant rabbit monoclonal antibodies,relying on their high affinity, low cross-reactivity, excellent oligonucleotide labeling compatibility, and superior batch-to-batch consistency), provides GeoMx DSP users with reliable tools. This empowers researchers to deeply explore the spatiotemporal dynamics of protein function within complex tissue systems.

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