Human IL-34 shares a sequence identity of 99.6%, 72% and 71% with chimpanzee, rat, and mouse IL-34, respectively, on the amino acid level. The IL-34 gene is syntenic in the human, chimpanzee, rat, and mouse genomes. IL-34 has no apparent consensus structural domain or motif, and does not share sequence homology with M-CSF; nevertheless, it binds to the CSFR. These two cytokines are not identical in biological activity and signal activation. IL-34 and CSF show an equivalent ability to support cell growth or survival. However, these cytokines have differing ability to induce the production of chemokines (MCP-1 and eotaxin-2) in primary macrophages, the morphological change in TF-1-fms cells, and the migration of J774A.1 cells. The use of monoclonal antibodies against the CSFR suggests a differential domain binding in the receptor to IL-34 and CSF and, as a result, different bioactivities and signal activation kinetics/strength are produced for these cytokines.
The human IL-34 (Accession# NM_152456.2: Met1 - Pro242 with a C-terminal 8His tag) was expressed CHO cells.
Molecular Mass
The 222 amino acid recombinant protein has a predicted molecular mass of 26.7 kD. The DTT-reduced protein migrates at approximately 40 kD, and the non-reduced protein migrates with slightly greater mobility by SDS-PAGE.
Purity
>98%, as determined by Coomassie stained SDS-PAGE.
Formulation
Lyophilized in sterile-filtered PBS, pH 7.2, containing 1% BSA, 0.09% sodium azide, and protease inhibitors.
Endotoxin Level
Less than 0.01 ng per µg cytokine as determined by the LAL method.
Concentration
Lot-specific (please contact technical support for mass/vial, or use our Lookup tool if you have a lot number.)
Storage & Handling
Upon receipt, store unopened vials between 2°C and 8°C immediately and use within 12 months from date of receipt. Prior to use, reconstitute the lyophilized powder with 0.2 ml of PBS containing a carrier protein (e.g., 1% BSA, protease free), pH 7.4. Re-cap vial, vortex. Allow the reconstituted standard to sit at room temperature for 15 minutes, vortex again to mix completely. The reconstituted standard stock solution can be aliquoted into polypropylene vials and stored at -70°C for up to one month. Do not re-use diluted standards. Use a manual defrost freezer and avoid repeated freeze thaw cycles.
Each lot of this protein is quality control tested by ELISA assay. For use as an ELISA standard, a standard curve comprised of two-fold dilutions from 5000 pg/mL to 78 pg/mL is suggested. It is recommended that the reagent be titrated for optimal performance for each application.
Application Notes
This IL-34 protein is useful as a standard for a human IL-34 sandwich ELISA, using unlabeled E0320E7 antibody (Cat. No. 361301) for capture and biotinylated E033B8 antibody (Cat. No. 361401) for detection.
IL-34 mRNA is expressed in different tissues, including spleen, heart, brain, lung, liver, kidney, thymus, testes, ovary, small intestine, prostate, and colon.
Function
IL-34 increases monocyte's viability, induces macrophage proliferation, and synergizes with other cytokines to generate macrophages and osteoclasts from cultured progenitors. IL-34 promotes the formation of the colony-forming unit-macrophage (CFU-M) in human bone marrow culture. IL-34 supports RANKL-induced osteoclastogenesis by promoting the adhesion and proliferation of osteoclast progenitors. Human IL-34 promotes the osteoclast differentiation from peripheral blood mononucleated cells. In addition, systematic administration of IL-34 to mouse increases the number of CD11b+ cells and reduces bone mass. IL-1ß and TNF-α induce the expression of interleukin-34 mRNA in osteoblast. IL-34 is induced in macrophages infected with equine infectious anemia virus (EIAV).
Interaction
Macrophages, monocytes, myeloid cells
Ligand/Receptor
CSF-1R
Biology Area
Cell Biology, Immunology, Stem Cells
Molecular Family
Cytokines/Chemokines
Antigen References
1. Clanchy F, et al. 2006. J. Leukoc. Biol. 79:757.
2. Lin H, et al. 2008. Science 320:807.
3. Chihara T, et al. 2010. Cell. Death Differ. 17:1917.
4. Wei S, et al. 2010. J. Leukoc. Biol. 88:495.
5. Eda H, et al. 2011. Rheumatol. Int. 31:1525.
