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Recombinant In Vivo Grade Anti-Fluorescein Antibody

Recombinant Anti-FITC Antibody, Anti-FITC Isotype Control, Anti-Fluorescein Isothiocyanate Monoclonal Antibody

Catalog No.	Product Name	Size	List Price (US$)
PA007742.h1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1 Kappa	1 mg	300.00
PA007742.h1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1 Kappa	5 mg	650.00
PA007742.h1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1 Kappa	25 mg	1500.00
PA007742.h1LA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1-L234A L235A P329G (LALAPG) Kappa	1 mg	300.00
PA007742.h1LA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1-L234A L235A P329G (LALAPG) Kappa	5 mg	650.00
PA007742.h1LA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1-L234A L235A P329G (LALAPG) Kappa	25 mg	1500.00
PA007742.hf	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human Fab Fragment	1 mg	900.00
PA007742.m2a	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a Kappa	1 mg	150.00
PA007742.m2a	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a Kappa	5 mg	350.00
PA007742.m2a	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a Kappa	25 mg	900.00
PA007742.m1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG1 Kappa	1 mg	300.00
PA007742.m1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG1 Kappa	5 mg	650.00
PA007742.m1	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG1 Kappa	25 mg	1500.00
PA007742.m2aLA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a-L234A L235A P329G (LALAPG) Kappa	1 mg	300.00
PA007742.m2aLA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a-L234A L235A P329G (LALAPG) Kappa	5 mg	650.00
PA007742.m2aLA	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a-L234A L235A P329G (LALAPG) Kappa	25 mg	1500.00
PA007742.mf	In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse Fab Fragment	1 mg	900.00

Note

Recombinant mouse IgG2a isotype controls and Recombinant human IgG1 isotype controls are available. Condition of sample preparation and optimal sample dilution should be determined experimentally by the investigator.
Note

Price/availability/specifications subject to change without notice. Unless otherwise indicated, our catalog and customized products are for research use only and not intended for human or animal diagnostic or therapeutic use.
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Description

Background of Recombinant In Vivo Grade Anti-Fluorescein Antibody (Clone: 4-4-20 Enhanced)

Our Recombinant In Vivo Grade Anti-Fluorescein Antibody (Clone 4-4-20 enhanced) is a sequence-defined, mammalian-expressed recombinant human IgG1 anti-FITC molecule engineered to deliver the exceptional batch-to-batch consistency and high structural integrity required for rigorous functional assays. This premium low endotoxin fluorescein antibody specifically recognizes and binds to fluorescein (FITC) attached to proteins, peptides, nucleic acids, or solid matrices with extremely high affinity. Serving as a highly specific second-step reagent for detecting FITC-conjugated targets, this antibody is an indispensable tool for Western Blot, Flow Cytometry, and advanced in vivo tracking applications where preventing target dissociation is critical.

The fluorescein/anti-fluorescein detection system provides a massive strategic advantage over the traditional biotin-streptavidin system, particularly in complex tissue environments and animal models. Endogenous biotin is naturally present in a large variety of biological samples, which frequently leads to high background noise, reduced sensitivity, or false negatives and false positives in biotin-based assay formats. Because fluorescein (FITC) is entirely absent in natural biological samples, deploying our recombinant human IgG1 anti-FITC antibody completely eliminates endogenous background interference. This absence of native cross-reactivity guarantees an exceptional signal-to-noise ratio, making it ideal for high-sensitivity immunoassay signal amplification techniques.

To support diverse diagnostic development and industrial scale-up, Syd Labs offers flexible custom engineering options for our anti-fluorescein platforms. Please contact us to request a quote for engineered anti-fluorescein (FITC) antibody mutants of various species/isotypes, effector-silent frameworks, or variants featuring recombinant Avi-, His-, and DYKDDDDK-tags for streamlined solid-phase immobilization. A robust selection of direct conjugates?including premium biotinylated antibodies and direct labeling with an array of custom dyes, enzymes, and fluorophores?is fully available to meet your exact experimental specifications.

PA007742.h1: In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Human IgG1 Kappa

Recombinant human IgG1 Monoclonal Antibody.
Clone: 4-4-20 (enhanced).
Isotype: Human IgG1 kappa.
Source: The recombinant anti-Fluorescein (FITC) monoclonal antibody (clone: 4-4-20 (enhanced)) was produced in mammalian cells.
Specificity/Sensitivity: The recombinant anti-Fluorescein (FITC) monoclonal antibody (clone: 4-4-20 (enhanced)) specifically binds to Fluorescein (FITC).
Applications: Western Blot, Flow Cytometry.
Form of Antibody: 0.2 μM filtered solution of 1x PBS.
Purity: >95% by SDS-PAGE under reducing conditions and HPLC.

PA007742.m2a: In Vivo Grade Recombinant Anti-Fluorescein (FITC) Monoclonal Antibody (Clone: 4-4-20 (enhanced)), Mouse IgG2a Kappa

Recombinant mouse IgG2a monoclonal antibody.
Clone: 4-4-20 (enhanced).
Isotype: Mouse IgG2a kappa.
Source: The recombinant anti-Fluorescein (FITC) monoclonal antibody (clone: 4-4-20 (enhanced)) was produced in mammalian cells.
Specificity/Sensitivity: The recombinant anti-Fluorescein (FITC) monoclonal antibody (clone: 4-4-20 (enhanced)) specifically binds to Fluorescein (FITC).
Applications: Western Blot, Flow Cytometry.
Form of Antibody: 0.2 μM filtered solution of 1x PBS.
Purity: >95% by SDS-PAGE under reducing conditions and HPLC.

Shipping: The recombinant anti-fluorescein (FITC) monoclonal antibody of clone 4-4-20 (enhanced) is shipped with ice pack. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70°C as supplied.
1 month from date of receipt, 2 to 8°C as supplied.

References of Recombinant In Vivo Grade Anti-Fluorescein Antibody (Clone: 4-4-20 Enhanced)

Key Application: Utilization of anti-fluorescein clone 4-4-20 scFv in switchable CAR-T cell therapies for controllable in vivo tumor targeting and tracking.

Versatile strategy for controlling the specificity and activity of CAR T cells

J. S. Y. Ma, et al. Proc Natl Acad Sci U S A. 2016 Jan 26;113(4):E450-8. doi: 10.1073/pnas.1524193113. PMID: 26764355

To mitigate toxicity and broaden the applicability of CAR-T cell therapies, a versatile, switchable platform was engineered using a recombinant anti-fluorescein (FITC) single-chain variable fragment (scFv) derived from clone 4-4-20. The switchable CAR-T cells do not bind to normal tissues but explicitly target fluorescein-conjugated tumor-specific antibodies. This framework allows for precise, dose-dependent control of T cell activity and proliferation in vivo via the administration of the FITC-labeled targeting molecules, demonstrating the stability and target-binding integrity of the 4-4-20 antigen-binding structure within animal models.

(Tags: In Vivo Grade Anti-Fluorescein Antibody; Clone 4-4-20 Enhanced; In Vivo Tracking; Recombinant Human IgG1 Anti-FITC)

Key Application: Recombinant expression, rapid refolding, and high-efficiency purification of anti-fluorescein single-chain antibodies (clone 4-4-20).

Rapid refolding and polishing of single-chain antibodies from Escherichia coli inclusion bodies

Jessica R Sinacola, et al. Protein Expr Purif. 2002 Nov;26(2):301-8. doi: 10.1016/s1046-5928(02)00538-7. PMID: 12406685

The anti-fluorescein single-chain antibody 4-4-20 was expressed as inclusion bodies in E. coli for use in a comparative refolding study. Although various methods produced active protein for 4-4-20, the extent of aggregation differed greatly among the formulation parameters. A significant decrease in the fluorescent intensity of a fluorescein solution is observed upon the binding of fluorescein to the active site of 4-4-20, establishing a gold-standard benchmark for monitoring antibody-ligand interactions and proving the high-affinity stability of the sequence-defined 4-4-20 binding pocket.

(Tags: Recombinant Anti-FITC; Clone 4-4-20 Enhanced; Antibody Binding Stability; Flow Cytometry Reagent)

Key Application: Structural and thermodynamic validation of mouse-human chimeric anti-fluorescein antibody frameworks (clone 4-4-20) for human-compatible research fields.

Comparative thermodynamic analysis of the antigen-binding site of a mouse-human chimeric anti-fluorescein antibody

W. D. Mallender, et al. Biochemistry. 1999 Dec 14;38(50):16521-31. doi: 10.1021/bi9915951. PMID: 10600115

Characterization of the mouse-human chimeric variable domains of clone 4-4-20 demonstrates high-affinity binding kinetics to fluorescein ligands. The integration of human constant regions preserves the structural integrity and binding thermodynamics of the original 4-4-20 active site. This chimeric design successfully eliminates endogenous anti-species background interference in complex biological matrices while maintaining exceptional stability, making it an optimal framework for low-endotoxin functional assays and advanced analytical tracking.

(Tags: Recombinant Human IgG1 Anti-FITC; Low Endotoxin Fluorescein Antibody; Functional Assays; Clone 4-4-20)

Explore Alternative Recombinant Anti-Fluorescein (FITC) Formats

Depending on your specific application requirements, we provide classic in vitro standards and engineered ultra-high affinity alternatives to fully support your research platform:

For Routine In Vitro Assays (ELISA, WB, IHC):
Recombinant Anti-Fluorescein Antibody Clone 4-4-20 - Optimized as a highly consistent second-step capture or detection reagent for standard laboratory immunoassay systems.
For Ultra-Sensitive Detection & Signal Amplification:
Anti-FITC Antibody Clone 4M5.3 - Engineered via directed evolution to deliver an unprecedented 270 fM femtomolar affinity, eliminating target dissociation in next-gen digital ELISAs and biosensors.

Syd Labs provides the following recombinant anti-Biotin/Digoxin/DNP/Fluorescein monoclonal antibodies:
Recombinant Anti-Biotin Monoclonal Antibodies (Clone F1)
Recombinant Anti-Biotin Monoclonal Antibodies (Clone M33)
Recombinant Anti-Digoxin Monoclonal Antibodies (Clone 5A7)
Recombinant Anti-Digoxin Monoclonal Antibodies (Clone 26-10)
Recombinant Anti-DNP Monoclonal Antibodies (Clone DNP.m3)

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