FPA Antibody
Description
Introduction to FPA Antibodies
FPA antibodies are specialized immunoglobulin molecules targeting distinct antigens across biomedical research and clinical diagnostics. The term "FPA" encompasses multiple contexts: Fibrinopeptide A (a coagulation biomarker), α-fodrin (an autoimmune disease target), FGFR2b (a cancer-associated receptor), and Fluorescence Polarization Assay (a diagnostic technology). This article synthesizes data on these variants, emphasizing their structural characteristics, clinical applications, and research significance.
FPA Antibodies Targeting Fibrinopeptide A (FPA)
Fibrinopeptide A (FPA) is a 16-amino-acid peptide cleaved from fibrinogen during blood clot formation. Antibodies against FPA are critical for studying thrombin activity and coagulation disorders.
Key Features:
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Clone 1F7: A monoclonal mouse IgG2a antibody (ABIN235161) specific to human FPA, used in ELISA and protein assays .
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Clinical Utility:
Table 1: FPA Antibody Performance in Coagulation Studies
| Application | Sensitivity | Specificity | Clinical Use Case |
|---|---|---|---|
| Radioimmunoassay | 50 pg/ml | High | DIC diagnosis |
| Ethanol precipitation | 75% recovery | No cross-reactivity | Thrombosis monitoring |
α-FPA Antibodies in Sjögren’s Syndrome (SS)
α-FPA antibodies target a conserved peptide in α-fodrin, a cytoskeletal protein linked to autoimmune exocrinopathy.
Research Findings :
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Sensitivity: 73% in primary SS (vs. 51.4% for anti-SSA).
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Specificity: 81.8% (vs. 64.7% for anti-SSA).
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Clinical Correlation: Associated with extraglandular manifestations (e.g., pulmonary fibrosis, vasculitis).
Table 2: Diagnostic Performance of α-FPA in Sjögren’s Syndrome
| Antibody | Sensitivity (%) | Specificity (%) | PPV (%) | NPV (%) |
|---|---|---|---|---|
| α-FPA | 73.0 | 81.8 | 100 | 91.6 |
| Anti-SSA | 51.4 | 64.7 | 100 | 75.5 |
FPA144: An Anti-FGFR2b Antibody in Oncology
FPA144 is a glycoengineered monoclonal antibody targeting fibroblast growth factor receptor 2b (FGFR2b), overexpressed in gastric, ovarian, and breast cancers.
Phase I Trial Highlights :
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Safety: No dose-limiting toxicities observed at ≤6 mg/kg q2w.
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Pharmacokinetics: Non-linear clearance due to receptor-mediated mechanisms.
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Ongoing Studies: Dose escalation continues to assess antitumor activity.
Fluorescence Polarization Assay (FPA) Technology
FPA leverages antibody-antigen binding dynamics for rapid diagnostics.
Brucellosis Detection :
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Principle: Fluorescently labeled antigen-antibody complexes increase polarization (mP units).
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Performance:
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Sensitivity: 94.5% vs. SAT (96.6% coincidence rate).
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Specificity: 100% (no cross-reactivity with non-Brucella pathogens).
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Table 3: FPA vs. Serological Tests in Brucellosis
| Test | Sensitivity (%) | Specificity (%) | Kappa Value |
|---|---|---|---|
| FPA | 94.5 | 100 | 0.93 |
| ELISA | 80.5 | 100 | 0.80 |
Research and Clinical Implications
FPA antibodies demonstrate versatility across disciplines:
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- The crystal structure of Arabidopsis thaliana FPA SPOC domain has been determined at a resolution of 2.7 Å. PMID: 27513867
- The recovery of native ZOU gene expression in the spz2 zou-4 double mutant is attributed to transcriptional read-through of the intronic T-DNA, resulting from decreased proximal polyadenylation. PMID: 27164978
- Research has shown that defective termination at specific loci in fpa mutants is shared with dicer-like 1 (dcl1) or dcl4 mutants, prompting alternative explanations for the silencing roles of these proteins. PMID: 24204292
- FCA and FPA play significant roles in the A. thaliana genome by regulating RNA 3' processing and transcription termination, thus limiting intergenic transcription. PMID: 21536901
- FPA functions redundantly with FCA, another RNA binding protein involved in flowering and RNA silencing, to control the expression of alternatively polyadenylated antisense RNAs at the locus encoding the floral repressor FLC. PMID: 20079695
- It is proposed that FCA and FPA regulate chromatin silencing of single and low-copy genes, interacting in a locus-dependent manner with the canonical small interfering RNA-directed DNA methylation pathway to regulate common targets. PMID: 17916737
