LEAF™ Purified anti-mouse FR4 (Folate Receptor 4) Antibody

Pricing & Availability
TH6 (See other available formats)
Other Names
Folate receptor 4, FBP3, FR δ
Rat IgG2b, κ
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Product Citations
C57BL/6 mouse splenocytes stained with CD3 (145-2C11) APC and LEAF™ purified TH6, followed by anti-rat IgG PE.
  • TH6_LEAF_022309.jpg
    C57BL/6 mouse splenocytes stained with CD3 (145-2C11) APC and LEAF™ purified TH6, followed by anti-rat IgG PE.
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125102 500 µg $450
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Folate receptor 4 (FR4) is a surface receptor for folic acid (Vitamin B9). It was recently reported that FR4 is highly and constitutively expressed on mouse CD4+CD25+ natural regulatory T (Treg) cells. The high expression of this surface marker in combination with CD4 and CD25 can be used to distinguish T reg cells from other types of T cells. Since FR4 is a surface marker, this antibody can be used in combination with anti-CD25 and/or CD4 to sort living Treg cells for functional studies.

Product Details
Technical data sheet

Product Details

Mouse Folate Receptor 4
Antibody Type
Host Species
0.2 µm filtered in phosphate-buffered solution, pH 7.2, containing no preservative. Endotoxin level is <0.1 EU/µg of the protein (<0.01 ng/µg of the protein) as determined by the LAL test.
The LEAF™ (Low Endotoxin, Azide-Free) antibody was purified by affinity chromatography.
1.0 mg/ml
Storage & Handling
The antibody solution should be stored undiluted between 2°C and 8°C. This LEAF™ solution contains no preservative; handle under aseptic conditions.

FC - Quality tested
Cyt, Depletion - Reported in the literature

Recommended Usage

Each lot of this antibody is quality control tested by immunofluorescent staining with flow cytometric analysis. For flow cytometric staining, the suggested use of this reagent is ≤ 1.0 µg per 106 cells in 100 µl volume. It is recommended that the reagent be titrated for optimal performance for each application.

Application References

(PubMed link indicates BioLegend citation)
  1. Yamaguchi T et al. 2007. Immunity 27:145.
  2. Houout R and Levy R. 2009. Blood. 113:3546. (Depletion)
  3. Teng M et al. 2010. Cancer Res. 70:2665. (Depletion)
Product Citations
  1. Inoue N, et al. 2015. Nat Commun. 6: 8858. PubMed
  2. Kato K, et al. 2016. Nat Commun. 7:12198. PubMed
Publication Library
AB_1027724 (BioLegend Cat. No. 125102)

Antigen Details

28.2 Kd protein consisting of 244 amino acids

Expressed in mouse thymus and spleen. Highly expressed on natural regulatory T (Treg) cells. However, expression of the human gene was not detected in multiple samples from both adult and embryonic tissue sources.

folic acid
Cell Type
Biology Area
Immunology, Innate Immunity
Antigen References

1. Yamaguchi T, et al.:2007. Immunity 27 (1):145
2. Spiegelstein O, et al. 2000. Gene 258:117

Gene ID
64931 View all products for this Gene ID
View information about FR4 on UniProt.org

Related FAQs

Does BioLegend test each LEAF™ antibody by functional assay?

No, BioLegend does not test LEAF™ antibodies by functional assays unless otherwise indicated. Due to the possible complexities and variations of uses of biofunctional antibodies in different assays and because of the large product portfolio, BioLegend does not currently perform functional assays as a routine QC for the antibodies. However, we do provide references in which the antibodies were used for functional assays and we do perform QC to verify the specificity and quality of the antibody based on our strict specification criteria.

Do you guarantee that your antibodies are totally pathogen free?

BioLegend does not test for pathogens in-house aside from the GoInVivo™ product line. However, upon request, this can be tested on a custom basis with an outside, independent laboratory.

Does BioLegend test each LEAF™ antibody for potential pathogens?

No, BioLegend does not test for pathogens in-house unless otherwise indicated.  However, we can recommend an outside vendor to perform this testing as needed.

Have you tested this LEAF™/Ultra-LEAF™ antibody for in vivo or in vitro applications?

We don't test our antibodies for in vivo or in vitro applications unless otherwise indicated. Depending on the product, the TDS may describe literature supporting usage of a particular product for bioassay. It may be best to further consult the literature to find clone specific information.

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For research use only. Not for diagnostic use. Not for resale. BioLegend will not be held responsible for patent infringement or other violations that may occur with the use of our products.


*These products may be covered by one or more Limited Use Label Licenses (see the BioLegend Catalog or our website, www.biolegend.com/ordering#license). BioLegend products may not be transferred to third parties, resold, modified for resale, or used to manufacture commercial products, reverse engineer functionally similar materials, or to provide a service to third parties without written approval of BioLegend. By use of these products you accept the terms and conditions of all applicable Limited Use Label Licenses. Unless otherwise indicated, these products are for research use only and are not intended for human or animal diagnostic, therapeutic or commercial use.


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