Cell Signaling Technology

Product Pathways - Growth Factors/Cytokines

Human Interleukin-28A (hIL-28A/IFN-λ2) #5164

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Source

Recombinant human IL-28A (hIL-28A) Val26-Val200 (Accession #NP_742150) was expressed in human 293 cells at Cell Signaling Technology.

Molecular Characterization

Based on amino acid sequencing, greater than 60% of recombinant hIL-28A starts at Val26 (VPVAR) and has a calculated MW of 19,754. The remainder starts at Pro27 (PVARL) or Val28 (VARLH). DTT-reduced and non-reduced protein migrate as 21 kDa polypeptides.

Purity

>98% as determined by SDS-PAGE of 6 μg reduced (+) and non-reduced (-) recombinant hIL-28A. All lots are greater than 98% pure.

Bioactivity

The bioactivity of recombinant hIL-28A was determined in a virus protection assay. The ED50 of each lot is between 10-60 ng/ml.

Coomassie Gel

Coomassie Gel

The purity of recombinant hIL-28A was determined by SDS-PAGE of 6 µg reduced (+) and non-reduced (-) recombinant hIL-28A and staining overnight with Coomassie Blue.

Bioactivity

Bioactivity

The bioactivity of hIL-28A was determined in a virus protection assay. Hep G2 cells were pre-treated with increasing concentrations of hIL-28A for 24 hours. Cells were then inoculated with encephalomyocarditis virus (EMCV) and incubated for an additional 48 hours. Surviving cells were fixed and stained with crystal violet and the OD595 was determined.

Western Blotting

Western Blotting

Western blot analysis of extracts from Hep G2 cells, untreated or treated with hIL-28A for 30 minutes, using Phospho-Stat3 (Tyr705) (D3A7) Rabbit mAb #9145 (upper) and Stat3 Antibody #9132 (lower).


Endotoxin

Less than 0.01 ng endotoxin/1 μg hIL-28A.

Formulation

With carrier: Lyophilized from a 0.22 μm filtered solution of PBS, pH 7.2 containing 20 μg BSA per 1 μg hIL-28A. Carrier free: Lyophilized from a 0.22 μm filtered solution of PBS, pH 7.2.

Background

IL-28A is a member of the Interferon λ family of cytokines, which includes IL-29 and IL-28B (1). IL-28A is produced by a number of cell types and shares many functions with Type I Interferons (1-3). IL-28A exhibits anti-viral activities in vitro and in vivo (1,2). IL-28A directly inhibits tumor cell proliferation and promotes anti-tumor immune responses in vivo (1,3). The IL-28 receptor is a heterodimer of the IL28-Rα and IL10-RI (1). IL-28A activates Stat1, Stat3, and Stat5 (1). IL-28Rα expression is limited to a few cell types, including plasmacytoid DC and epithelial cells (1).

  1. Li, M. et al. (2009) J Leukoc Biol 86, 23-32.
  2. Ank, N. et al. (2006) J Virol 80, 4501-9.
  3. Numasaki, M. et al. (2007) J Immunol 178, 5086-98.

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