- Other Names
- SLAMF4, SLAM family member 4, 2B4, Natural killer cell receptor 2B4, NK cell activation-inducing ligand, NAIL, NK cell type I receptor protein 2B4, NKR2B4, h2B4, signaling lymphocytic activation molecule 4, CD244
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SLAMF4, also known as 2B4 and CD244, is one of the members of the CD2 subfamily. It is expressed on NK cells, monocytes, basophils, TCR γ/δ T cells, and a subset of CD8+ T cells. Engagement of SLAMF4 by antibodies or a natural ligand, such as CD48, leads to tyrosine phosphorylation of SLAMF4, cell-mediated cytotoxicity and IFN-γ secretion by NK cells. Except CD48 ligation, SLAMF4-mediated non-MHC-restricted cell cytotoxicity is also dependent on others NCRs, such as NKp46 (NCR1/CD335). However, engagement of SLAMF4 with inhibitory receptors, such as KIR2DL1 or NKG2 (CD94), blocks SLAMF4-mediated cell cytotoxicity and cytokine production. The cytoplasmic region of SLAMF4 contains several immunoreceptor tyrosine-based switch motifs (ITSMs), which serve as activating and inhibitory regulatory elements for SLAMF4-mediated signaling. Its ITSMs can not only bind to SAP and Src kinase Fyn but also recruit the inhibitory kinase, Csk, and phosphatase SHP-1, SHP-2, and SHIP, leading to positive and negative signaling on cells. The activating and inhibitory functions are dependent on the density of surface expression of SLAMF4, degree of ligation, and the level of the adaptor molecule SAP expression. In XLP (X-linked lymphoproliferative disease) patients, SLAMF4 engagement cannot activate NK cells due to impairment of SAP/SH2D1A association. It has shown that SLAMF4 interacts with CD48 and functions as a costimulatory molecule, playing a critical role in cell proliferation and MHC-restricted cytotoxicity in CD8+ T cells. SLAMF4 expression also correlates with T cell differentiation. CD8+ effector αβ T cells predominantly express surface SLAMF4 with high levels of granzyme B and perforin expression, and rapid production of IFN-γ.Product Details
- Human SLAMF4, amino acid (Cys22-Arg221) (Accession: # NP_057466.1), with a linker (GSSR) and a C-terminal human IgG (Pro100-Lys330), was expressed in 293E cells.
- Molecular Mass
- The 435 amino acid recombinant protein has a predicted molecular mass of approximately 48.58 kD. The DTT-reduced and non-reduced protein migrates at between 66 kD and 120 kD respectively by SDS-PAGE. The predicted N-terminal amino acid is Cys.
- >95%, as determined by Coomassie stained SDS-PAGE.
- 0.22 μm filtered protein solution is in PBS pH7.2.
- Endotoxin Level
- Less than 0.1 EU per μg protein as determined by the LAL method.
- 10 and 25 µg sizes are bottled at 200 µg/mL. 100 µg and larger sizes are lot-specific and bottled at the concentration indicated on the vial (please contact technical support for concentration, or use our Lookup tool if you have a lot number.)
- Storage & Handling
- Unopened vial can be stored between 2°C and 8°C for one month, at -20°C for six months, or at -70°C for one year. For maximum results, quick spin vial prior to opening. The protein can be aliquoted and stored at -20°C to -70°C. Stock solutions can also be prepared at 50 - 100 µg/mL in sterile buffer (PBS, HPBS, DPBS, or EBSS) containing carrier protein such as 0.2 - 1% BSA or HSA and stored in working aliquots at -20°C to -70°C. Avoid repeated freeze/thaw cycles.
- The ED50 is 0.5 - 2.5 µg/mL, as measured by the ability of immobilized protein to induce IFN-γ production by NK-92 cells. Human IFN-γ ELISA MAX™ Deluxe Kit (Cat. No. 430104) was used to measure IFN-γ production.
- Application Notes
BioLegend carrier-free recombinant proteins provided in liquid format are shipped on blue ice. Our comparison testing data indicates that when handled and stored as recommended, the liquid format has equal or better stability and shelf-life compared to commercially available lyophilized proteins after reconstitution. Our liquid proteins are validated in-house to maintain activity after shipping on blue ice and are backed by our 100% satisfaction guarantee. If you have any concerns, contact us at email@example.com.
- CD2 subfamily
NK cells, monocytes and basophils, TCR γ/δ T cells, and a subset of CD8+ T cells.
- Engagement of SLAMF4 with CD48 stimulates cell-mediated cytotoxicity and cytokine secretion.
- Fyn, SAP/SH2D1A, Csk, SHP-1, SHP-2, SHIP
- Recombinant human SLAMF4 induces the production of IFN-γ in human NK-92 cells.
- Cell Type
- Basophils, Monocytes, NK cells, T cells
- Biology Area
- Molecular Family
- CD Molecules, Soluble Receptors
- Antigen References
- Parolini S, et al. 2000. J Exp Med. 192: 337.
- Watzl C, et al. 2000. J Immunol. 165: 3545.
- Brown MH, et al. 1998. J Exp Med. 188: 2083.
- Watzl C, et al. 2000. J Immunol. 165: 3545.
- Eissmann P, et al. 2005. Blood. 105: 4722.
- Latchman Y, et al. 1998. J Immunol. 161: 5809.
- Speiser DE, et al. 2001. J Immunol. 167: 6165.
- Lee KM, et al. 2003. J Immunol. 170: 4881.
- Kambayashi T, et al. 2001. J Immunol. 167: 6706.
- Tangye SG, et al. 1999. J Immunol. 162: 6981.
- Nakajima H, et al. 1999. Eur J Immunol. 29: 1676.
- Schuhmachers G, et al. 1995. Eur J Immunol. 25: 1117.
- Sivori S, et al. 2000. Eur J Immunol. 30: 787.
- Gene ID
- 51744 View all products for this Gene ID
- View information about SLAMF4 on UniProt.org
- Does specific activity of a recombinant protein vary between lots?
Specific activity will vary for each lot and for the type of experiment that is done to validate it, but all passed lots will have activity within the established ED50 range for the product and we guarantee that our products will have lot-to-lot consistency. Please conduct an experiment-specific validation to find the optimal ED50 for your system.
- Have your recombinants been tested for stability?
Our testing shows that the recombinant proteins are able to withstand room temperature for a week without losing activity. In addition the recombinant proteins were also found to withstand four cycles of freeze and thaw without losing activity.
- How do you convert activity as an ED50 in ng/ml to a specific activity in Units/mg?
- Use formula Specific activity (Units/mg) = 10e6/ ED50 (ng/mL)
- How does the activity of your recombinant proteins compare to competitors?
We quality control each and every lot of recombinant protein. Not only do we check its bioactivity, but we also compare it against other commercially available recombinant proteins. We make sure each recombinant protein’s activity is at least as good as or better than the competition’s. In order to provide you with the best possible product, we ensure that our testing process is rigorous and thorough. If you’re curious and eager to make the switch to BioLegend recombinants, contact your sales representative today!
- What is the specific activity or ED50 of my recombinant protein?
The specific activity range of the protein is indicated on the product datasheets. Because the exact activity values on a per unit basis can largely fluctuate depending on a number of factors, including the nature of the assay, cell density, age of cells/passage number, culture media used, and end user technique, the specific activity is best defined as a range and we guarantee the specific activity of all our lots will be within the range indicated on the datasheet. Please note this only applies to recombinants labeled for use in bioassays. ELISA standard recombinant proteins are not recommended for bioassay usage as they are not tested for these applications.