• Purity

  >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie? Blue Staining.

• Endotoxin Level

  <0.10 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its ability to induce IL-8 secretion by A375 human melanoma cells. The ED    ₅₀ for this effect is 3-15 ng/mL.

• Source

  Human embryonic kidney cell, HEK293-derived

  rhLT alpha (Leu35-Leu205) Accession # P01374	GGGGS	rhLT beta (Gln49-Gly244) Accession # Q06643	GGGGS	rhLT beta (Gln49-Gly244) Accession # Q06643
  N-terminus				C-terminus

• N-terminal Sequence    
  Analysis

  Leu35

• Structure / Form

  GS-linked heterotrimer    
   

• Predicted Molecular Mass

  61 kDa

• SDS-PAGE

  65-76 kDa, reducing conditions

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

Background: Lymphotoxin

Lymphotoxin alpha (LT-alpha ), and Lymphotoxin beta (LT-beta ) are pro-inflammatory TNF superfamily ligands that play important roles in immune system development (1, 2). The 25 kDa mature human LT-alpha is a secreted protein that shares 75% amino acid (aa) sequence identity with mouse and rat LT-alpha (3, 4). The 33 kDa mature human LT-beta is a type II transmembrane protein that shares 73% aa sequence identity with mouse and rat LT-beta within common regions of their extracellular domains (5). Relative to the human protein, mouse and rat LT-beta have a 66 aa or 65 aa insertion within the ECD, respectively. LT-alpha can be secreted as a homotrimer that binds and activates TNF RI/TNFRSF1A, TNF RII/TNFRSF1B, HVEM/TNFRSF14, and Troy/TNFRSF19 (6-8). LT-alpha is required for development of the spleen, lymph nodes, and Peyer’s patches (9). It also regulates T cell homing to the gut and IgA induction (10). In addition, LT-alpha can form membrane-associated heterotrimers with two copies of LT-beta on the surface of B, T, LTi, and ILC3 cells (2, 5, 11). The Lymphotoxin alpha 1/ beta 2 heterotrimer binds and activates the Lymphotoxin beta R/TNFRSF3 (LT beta R) which is expressed on macrophages, dendritic cells, hepatocytes, intestinal epithelial cells (IEC), follicular dendritic cells (FDC), and high endothelial venules (HEV) (2, 12, 13). LT beta R also serves as a receptor for LIGHT/TNFSF14 (14). LT-alpha 1/ beta 2 promotes the development of FDC networks and HEV in lymphoid tissue, the class switching of immature B cells for IgA production, and the production of homeostatic IL-22 by ILCs (10, 15-17). It can be shed by ADAM17 or MMP-8 mediated cleavage, and the released heterotrimer circulates in the serum and is elevated in synovial fluid of rheumatoid arthritis patients (18).

• References:

1. Lu, T.T. and J.L. Browning (2014) Front. Immunol. 5:47.

2. Upadhyay, V. and Y.-X. Fu (2014) Cytokine Growth Factor Rev. 25:227.

3. Gray, P.W. et al. (1984) Nature 312:721.

4. Nedwin, G.E. et al. (1985) J. Cell Biochem. 29:171.

5. Browning, J.L. et al. (1993) Cell 72:847.

6. Schoenfeld, H.J. et al. (1991) J. Biol. Chem. 266:3863.

7. Mauri, D.N. et al. (1998) Immunity 8:21.

8. Hashimoto, T. et al. (2008) Cell Cycle 7:106.

9. De Togni, P. et al. (1994) Science 264:703.

10. Kruglov, A.A. et al. (2013) Science 342:1243.

11. Androlewicz, M.J. et al. (1992) J. Biol. Chem. 267:2542.

12. Sudhamsu, J. et al. (2013) Proc. Natl. Acad. Sci. USA 110:19896.

13. Crowe, P.D. et al. (1994) Science 264:707.

14. Eldredge, J. et al. (2006) Biochemistry 45:10117.

15. Futterer, A. et al. (1998) Immunity 9:59.

16. Koni, P.A. et al. (1997) Immunity 6:491.

17. Ota, N. et al. (2011) Nat. Immunol. 12:941.

18. Young, J. et al. (2010) Cytokine 51:78.

• Entrez Gene IDs:

  4049 (Human); 16992 (Mouse)

• Alternate Names:

  Lymphotoxin