• Purity

  >95%, by SDS-PAGE under reducing conditions and visualized by silver stain

• Endotoxin Level

  <0.01 EU per 1 μg of the protein by the LAL method.  

• Activity

  Measured by its binding ability in a functional ELISA. In a 100 μL reaction mixture containing rhIL-28 R alpha /Fc Chimera at 1 μg/mL and    
  rhIL-28A (Catalog # 1587-IL) dilutions at 1-1000 ng/mL, the concentration of rhIL-28A that produces 50% of the optimal binding response is found to be approximately 40-200 ng/mL.

• Source

  Mouse myeloma cell line, NS0-derived

  Human IL-28 R alpha (Arg21 - Ala228) Accession # Q8IU57	IEGRMD	Human IgG1 (Pro100 - Lys330)
  N-terminus		C-terminus

• Accession #

• N-terminal Sequence    
  Analysis

  Arg21

• Structure / Form

  Disulfide-linked homodimer

• Predicted Molecular Mass

  50.2 kDa (monomer)

• SDS-PAGE

  65-75 kDa, reducing conditions

Background: IL-28 R alpha/IFN-lambda R1

IL-28 R alpha (IL-28 receptor alpha subunit; also named interferon-lambda R1) is a type I transmembrane glycoprotein that is the cytokine receptor family 2 member 12 (CRF2-12) (1 - 4). It pairs with the IL-10 receptor beta subunit (IL-10 R beta, CRF2-4) to form the IL-28 R (1 - 4). Each subunit of this receptor can interact with the interferon-like cytokines (type III interferons) IL-28A (IFN-lambda 2), IL-28B (IFN-lambda 3) or IL-29 (IFN-lambda 1) (1 - 4). Human IL-28 R alpha cDNA encodes a 520 amino acid (aa) protein with a 20 aa signal peptide, a 208 aa extracellular domain (ECD) with a fibronectin type III motif and four potential N-glycosylation sites, a 21 aa transmembrane sequence, and a proline-rich and acidic 271 aa cytoplasmic domain. Eight isoforms have been sequenced, but their significance is unknown (3, 5). Isoforms of 211 and 244 aa appear to lack transmembrane sequences. These and other isoforms of 491, 437, 322, 283 and 184 aa have alternate N- or C-termini, or lack an internal sequence (aa 268 - 296). The mature human IL-28 R alpha ECD shares 67%, 66%, 78% and 74% aa sequence identity with mouse, rat, canine and bovine IL-28 R alpha, respectively. Some cross-species reactivity has been shown (6). IL-28 R is constitutively expressed in most tissues, but its ligands are mainly produced by antigen presenting cells in response to viruses and their products (2 - 6). Signaling through IL-28 R alpha is similar to that of receptors for type I IFNs, including tyrosine phosphorylation, activation of JAK tyrosine kinases, STAT phosphorylation and formation of the IFN-stimulated gene factor 3 (ISGF-3) transcription factor complex (1 - 7). This signaling pathway induces antiviral activity and upregulates MHC class I antigen expression (2 - 7). Anti-proliferative activity has also been shown for IL-28/IL-28 R (7).

• References:

1. Chen, Q. et al. (2006) Vitam. Horm. 74:207.

2. Meager, A. et al. (2005) Cytokine 31:109.

3. Sheppard, P. et al. (2003) Nat. Immunol. 4:63.

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

5. Entrez Accession # NP_775088, EAW95113, EAW95115, EAW95116, AAI39723, AAI01409.

6. Lasfar, A. et al. (2006) Cancer Res. 66:4468.

7. Dumoutier, L. et al. (2004) J. Biol. Chem. 279:32269.

• Long Name:

  Interleukin 28 Receptor alpha

• Entrez Gene IDs:

  163702 (Human); 242700 (Mouse); 362628 (Rat)

• Alternate Names:

  class II cytokine receptor CRF2/12; CRF2/12; CRF2-12; Cytokine receptor class-II member 12; Cytokine receptor family 2 member 12; IFN-lambda R1; IFN-lambda receptor 1; IFN-lambda-R1; IFNLR; IFNLR1; IL-28 R alpha; IL-28 receptor subunit alpha; IL28R alpha; IL-28R1; IL28RA; IL-28Ra; IL-28R-alpha; Interferon lambda receptor 1; interferon lambda, receptor 1; interleukin 28 receptor A; interleukin 28 receptor, alpha (interferon, lambda receptor); interleukin 28 receptor, alpha; interleukin or cytokine receptor 2; interleukin-28 receptor subunit alpha; LICR2; Likely interleukin or cytokine receptor 2