FAP Proteins, Antibody & Stable Cell Line

Fibroblast activation protein alpha (FAP), also known as seprase, is a type II transmembrane serine protease expressed on activated fibroblasts. It contains a short cytoplasmic region, a single transmembrane segment and a large extracellular catalytic domain, and is active as a cell-surface homodimer. Its expression is generally low in most healthy adult tissues but rises during wound healing, fibrotic remodeling and cancer-associated stromal activation. FAP has both dipeptidyl peptidase and endopeptidase activity and participates in extracellular-matrix remodeling and fibroblast–epithelial interactions. In solid tumors, FAP is frequently associated with cancer-associated fibroblasts, which can shape matrix architecture, restrict immune-cell access and support tumor growth, invasion and treatment resistance. Because FAP is found across the stromal compartment of many tumor types rather than being limited to one cancer lineage, it is being studied as a broadly applicable target for tumor imaging, drug delivery and microenvironment-directed therapy.

FAP-targeted drug development covers several therapeutic and diagnostic modalities. Radioligand imaging and radiopharmaceutical therapy are among the most clinically advanced approaches, with therapeutic programs reaching Phase II evaluation in selected advanced cancers. Antibody-based strategies include unconjugated antibodies, bispecific or T-cell-engaging formats, antibody–drug conjugates and cytokine-fusion systems, while FAP-activated prodrugs and small-molecule inhibitors are also under investigation. FAP-directed CAR-T therapy has entered Phase I testing, whereas many additional cell-therapy and antibody formats remain at the preclinical or early clinical stage. Current research aims to improve tumor retention, stromal penetration, immune activation and therapeutic selectivity. Combination strategies are also being explored to weaken the stromal barrier and improve the activity of tumor-cell-directed treatments. Major development challenges include heterogeneous FAP expression, differences among cancer-associated fibroblast subtypes and possible on-target effects in healing or fibrotic tissues.

DIMA BIOTECH provides an integrated FAP research portfolio comprising recombinant ECD proteins, a research-grade biosimilar reference antibody and a target-overexpressing stable cell line. The portfolio includes human, cynomolgus and mouse FAP ECD proteins with His or mouse Fc tags, providing flexible formats for antigen-based screening, species cross-reactivity studies, protein immobilization and binding assays. The Anti-FAP mAb (sibrotuzumab biosimilar) is available as a reference antibody and has been validated for flow cytometry, supporting cell-surface FAP detection, antibody benchmarking, clone comparison and assay development. A Hu_FAP K562 stable cell line with FACS validation is also available for evaluating antibody binding in a defined cell-surface context. Together, these proteins, antibody and stable cells can support ELISA, SPR, BLI, flow cytometry, affinity analysis, immunization, antibody screening and positive-control establishment. They provide coordinated tools for early research and drug-development programs involving FAP-targeted antibodies, bispecifics, ADCs, radiopharmaceuticals, cell therapies and other tumor-stroma-directed modalities.