ECM1 Antibody

What is ECM1 and what are its primary biological functions?

ECM1 (extracellular matrix protein 1) is a glycoprotein involved in multiple biological processes including bone formation, skin differentiation, and cell proliferation. It plays significant roles in angiostasis and has been implicated in cancer progression. The protein inhibits MMP9 proteolytic activity and contributes to the formation and metastasis of several cancer types including breast, thyroid, and hepatocellular cancers . ECM1 has also been identified as a critical factor in T-follicular helper (TFH) cell differentiation and germinal center B-cell responses, which are essential for high-affinity antibody production .

What are the key molecular characteristics of ECM1 protein?

ECM1 has a calculated molecular weight of 61 kDa (540 amino acids), though it typically appears as 55-61 kDa on Western blots due to post-translational modifications. The protein contains multiple functional domains, with the distal second tandem repeat domain and carboxyl-terminus (amino acids 359-559) representing immunodominant epitopes recognized by autoantibodies in conditions like lichen sclerosus . The protein is encoded by gene ID 1893 (NCBI) with UniProt ID Q16610, and its full sequence is available in GenBank (accession number BC023505) .

What properties should researchers consider when selecting an ECM1 antibody?

When selecting an ECM1 antibody, researchers should consider:

• Host species and isotype (e.g., Rabbit IgG for polyclonal antibodies like 11521-1-AP)

• Reactivity with target species (human, mouse, rat, etc.)

• Validated applications (WB, IHC, IF/ICC, IP, ELISA)

• Target epitope region (full-length vs. specific domains)

• Storage conditions and buffer compatibility

• Validation data in tissues/cell lines relevant to your research

• Published literature supporting antibody specificity and performance

What are the recommended dilutions and protocols for different applications of ECM1 antibody?

These dilutions should be considered starting points, and optimization is essential as results may be sample-dependent .

How can researchers develop a quantitative ELISA for detecting anti-ECM1 antibodies in clinical samples?

To develop a quantitative ELISA for anti-ECM1 antibodies:

• Generate recombinant ECM1 protein fragments, focusing on the immunodominant region (amino acids 359-559) containing the distal second tandem repeat and COOH-terminal region

• Coat ELISA plates with the purified recombinant protein at optimal concentration

• Block with appropriate buffer to minimize non-specific binding

• Incubate with patient sera at optimized dilution

• Detect bound antibodies using labeled secondary antibodies

• Establish a cutoff value based on ROC analysis (e.g., 0.328 AU as determined in lichen sclerosus studies)

• Include positive and negative controls to assess intraplate and interplate variation

This approach has demonstrated 80.0% sensitivity and 93.7% specificity for detecting anti-ECM1 antibodies in lichen sclerosus patients .

What cell and tissue models are validated for studying ECM1 expression and function?

The following models have been validated for ECM1 studies:

Cell lines:

• A549 cells (lung cancer)

• HepG2 cells (liver cancer)

• MCF-7 cells (breast cancer)

• L02 cells (normal liver)

• A375 cells (melanoma)

Tissue models:

• Mouse liver and kidney tissue

• Mouse and rat pancreas tissue

• Human thyroid cancer tissue

• Human breast cancer tissue

• Human lung cancer tissue

• Human pancreas cancer tissue

These models have shown reliable ECM1 expression and can be used to investigate its biological functions and pathological relevance .

How is ECM1 involved in autoimmune conditions like lichen sclerosus?

ECM1 serves as an autoantigen in lichen sclerosus, with approximately 80% of patients exhibiting IgG autoantibodies against this protein. These autoantibodies primarily target multiple epitopes within ECM1, with the highest reactivity against the distal second tandem repeat domain and carboxyl-terminus. The presence of these autoantibodies correlates with disease severity and can serve as a diagnostic marker. Although the exact pathogenic mechanism remains unclear, it's hypothesized that anti-ECM1 antibodies may disrupt protein-protein interactions in the extracellular matrix, contributing to the sclerotic changes observed in affected skin. An ELISA system targeting the immunodominant region (amino acids 359-559) has been developed for serological diagnosis with high sensitivity and specificity .

What is the role of ECM1 in T-follicular helper cell differentiation and antibody production?

ECM1 plays a critical role in promoting T-follicular helper (TFH) cell differentiation and subsequent antibody responses:

• ECM1 is highly expressed in TFH cells and is induced by IL-6 and IL-21

• ECM1 deficiency leads to impaired TFH differentiation, reduced germinal center formation, and decreased antigen-specific antibody production

• Mechanistically, ECM1 inhibits the IL-2–STAT5 signaling pathway, which is a negative regulator of TFH differentiation

• ECM1 down-regulates Blimp-1 expression while enhancing Bcl6 expression in TFH cells, promoting TFH lineage commitment

• Administration of recombinant ECM1 protein enhances TFH development, germinal center B-cell responses, and production of high-affinity antibodies

These findings highlight ECM1 as a potential therapeutic target for enhancing antibody responses in vaccination or infection contexts .

How does ECM1 contribute to cancer progression and metastasis?

ECM1 has been implicated in cancer pathogenesis through multiple mechanisms:

• It promotes cell migration and angiogenesis in various cancer types including breast, thyroid, and hepatocellular cancers

• ECM1 participates in tumor progression and malignant transformation

• It contributes to metastasis formation, potentially through regulation of cell-matrix interactions

• ECM1 inhibits MMP9 proteolytic activity, which may affect extracellular matrix remodeling during cancer progression

• Its expression has been detected in multiple cancer cell lines (A549, HepG2, MCF-7, A375) and cancer tissues

These findings suggest ECM1 as a potential biomarker and therapeutic target in cancer research, with its detection by immunohistochemistry potentially informative for diagnosis or prognosis .

How can researchers generate and purify recombinant ECM1 protein for functional studies?

To generate recombinant ECM1 protein:

• Design expression constructs targeting full-length ECM1 or specific domains (particularly amino acids 359-559 for immunodominant region)

• Express the protein using appropriate systems:

  • Bacterial expression systems for smaller fragments

  • Baculovirus expression system for full-length or larger fragments (recommended for maintaining proper folding)

• Include affinity tags (e.g., His-tag, GST, or Fc-fusion) to facilitate purification

• Purify using affinity chromatography followed by size exclusion chromatography

• Verify purity by SDS-PAGE and Western blotting

• Assess functionality through binding assays or functional tests

• For in vivo applications, ensure endotoxin removal and sterile filtration

Recombinant ECM1-Fc fusion proteins expressed via the Bac-to-Bac baculovirus system have been successfully used to enhance TFH differentiation and antibody production in mouse models .

What strategies can address cross-reactivity or non-specific binding when using ECM1 antibodies?

To minimize cross-reactivity and non-specific binding:

• Antibody validation:

  • Verify specificity using positive and negative controls

  • Include ECM1 knockout/knockdown samples when possible

  • Compare multiple antibodies targeting different epitopes

• Protocol optimization:

  • Increase blocking time and concentration (5% BSA or milk)

  • Optimize antibody dilution through titration experiments

  • Include detergents (0.1-0.3% Triton X-100 or Tween-20) in wash buffers

  • Reduce primary antibody incubation time

• Background reduction techniques:

  • For IHC, use appropriate antigen retrieval (TE buffer pH 9.0 recommended for ECM1)

  • For IF, include additional blocking steps with normal serum from secondary antibody host

  • For WB, increase wash duration and number of washes

• Signal verification:

  • Use peptide competition assays to confirm specificity

  • Include isotype controls to identify non-specific binding

How can researchers investigate ECM1's role in immune responses during viral infections?

To investigate ECM1's role in antiviral immune responses:

• In vivo infection models:

  • Challenge ECM1 knockout mice with viruses (e.g., influenza) and assess survival, viral clearance, and immune responses

  • Administer recombinant ECM1 protein to infected animals and monitor protection

  • Analyze TFH differentiation, germinal center formation, and neutralizing antibody production

• Mechanistic studies:

  • Examine ECM1 expression in different immune cell populations following viral infection

  • Assess the impact of ECM1 on signaling pathways (IL-2–STAT5, Bcl6, Blimp-1) in virus-specific T cells

  • Investigate ECM1's effect on antigen presentation and T cell-B cell interactions

• Translational approaches:

  • Test recombinant ECM1 as an adjuvant during vaccination

  • Evaluate correlations between ECM1 expression/anti-ECM1 antibodies and protection against viral infection

  • Develop ECM1-based therapies to enhance protective immunity

Preliminary studies have shown that recombinant ECM1 administration enhances TFH differentiation and neutralizing antibody production during influenza virus infection, suggesting potential therapeutic applications .

What are the potential applications of ECM1 antibodies in precision medicine and immunotherapy?

ECM1 antibodies show promise for precision medicine applications:

• Diagnostic biomarkers:

  • Serological diagnosis of autoimmune conditions like lichen sclerosus

  • Tissue expression profiling in cancer for prognostic assessment

• Therapeutic targeting:

  • Blocking ECM1 function in cancers where it promotes metastasis

  • Enhancing ECM1 activity to boost immune responses during vaccination

• Immune response modulation:

  • Using recombinant ECM1 as an adjuvant to enhance antibody responses

  • Targeting ECM1 pathways to modify TFH differentiation in autoimmunity

• Companion diagnostics:

  • Identifying patients likely to respond to therapies targeting ECM1-related pathways

  • Monitoring treatment efficacy through changes in ECM1 expression or anti-ECM1 antibody levels

How can epitope mapping of ECM1 advance understanding of its function in different pathological contexts?

Comprehensive epitope mapping of ECM1 can provide valuable insights:

• Domain-specific functions:

  • Correlating antibody targeting of specific domains with disease manifestations

  • Identifying critical functional regions through domain-specific blocking studies

• Structure-function relationships:

  • Mapping interaction sites with binding partners (e.g., MMP9, fibulins, laminins)

  • Determining which domains are essential for TFH cell differentiation

• Therapeutic development:

  • Designing domain-specific antibodies or inhibitors

  • Creating modified ECM1 proteins with enhanced or selective activities

• Disease mechanisms:

  • Comparing autoantibody epitope profiles across different autoimmune conditions

  • Analyzing epitope spreading during disease progression

Studies have already identified the distal second tandem repeat and COOH-terminal region (amino acids 359-559) as immunodominant in lichen sclerosus, providing a foundation for further epitope mapping in other conditions .

Citations Proteintech. (2025). ECM1 antibody (11521-1-AP). Retrieved from https://www.ptglab.com/products/ECM1-Antibody-11521-1-AP.htm Oyama, N., Chan, I., Neill, S. M., Hamada, T., South, A. P., Wessagowit, V., Wojnarowska, F., D'Cruz, D., Hughes, G. J., Black, M. M., & McGrath, J. A. (2004). Development of antigen-specific ELISA for circulating autoantibodies to extracellular matrix protein 1 in lichen sclerosus. Journal of Clinical Investigation, 113(11), 1550-1559. Yi, Y., Xu, Y., Wang, Y., Wang, W., Li, C., Wang, X., Xiong, T., Yi, Y., Wu, W., Yonggang, Z., Weijun, S., Xiaoxia, L., Chun-xia, L., & Zhu, L. (2018). Extracellular matrix protein 1 promotes follicular helper T cell differentiation and antibody production. Proceedings of the National Academy of Sciences, 115(34), 8621-8626.