• Purity

  >97%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

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

• Activity

  Measured in an anti-viral assay using HepG2 human hepatocellular carcinoma cells infected with encephalomyocarditis (EMC) virus. Sheppard, P.     et al. (2003) Nat. Immunol.     4:63. The ED    ₅₀ for this effect is 10-50 ng/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human IL-28A Val26-Val200 Accession # NP_742150	DI	6-His tag
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Val26

• Predicted Molecular Mass

  20.8 kDa

• SDS-PAGE

  24 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: IL-28A/IFN-lambda 2

IL-28A, IL-28B, and IL-29, also named interferon-lambda 2 (IFN-lambda 2), IFN-lambda 3, and IFN-lambda 1, respectively, are class II cytokine receptor ligands that are distantly related to members of the IL-10 family (11-13% aa sequence identity) and type I IFN family (15-19% aa sequence identity) (1-3). The genes encoding these three cytokines are localized to chromosome 19 and each is composed of multiple exons. The exon organization of these genes is also found in the IL-10 family genes but is distinct from the type I IFNs, which are encoded within a single exon. The expression of IL-28A, B, and IL-29 is induced by virus infection or double-stranded RNA. All three cytokines exert bioactivities that overlap those of type I IFNs, including antiviral activity and up-regulation of MHC class I antigen expression. The three proteins signal through the same heterodimeric receptor complex that is composed of the IL-10 receptor  beta (IL-10 R beta ) and a novel IL-28 receptor alpha (IL-28 R alpha, also known as IFN-lambda R1). Ligand binding to the receptor complex induces Jak kinase activation and STAT1 and STAT2 tyrosine phosphorylation. The phosphorylated STAT1 and STAT2 complex with IFN-regulatory factor 9 (IRF-9) to form the IFN-stimulated regulatory factor 3 (ISGF-3) transcription factor complex that is translocated to the nucleus. ISGF-3 binds to the IFN-stimulated response element (ISRE) present in the regulatory regions of the target genes. Human IL-28A cDNA encodes a 200 amino acid (aa) residue precursor protein with a putative 25 aa signal peptide. It shares 94% and 67% aa sequence identity with human IL-28B and human IL-29, respectively.

• References:

1. Vilcek, J. (2003) Nature Immunol. 4:8.

2. Sheppard, P. et al. (2003) Nature Immunol. 4:63.

3. Kotenko, S.V. et al. (2003) Nature Immunol. 4:69.

• Long Name:

  Interleukin 28A

• Entrez Gene IDs:

  282616 (Human)

• Alternate Names:

  interleukin-28A; IFN-lambda 2; IL28A; IL-28A; interferon, lambda 2