Effective Polarization of Human Th17 Cells with Biologically HumaXpress™ TGFβ1, β2, TGFβ3

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Introduction

Transforming growth factors beta (TGFβ are highly pleiotropic cytokines that act as cellular switches and regulate immune function, proliferation and epithelial-mesenchymal transition. These proteins are produced as precursors. A furin-like convertase processes the proprotein to generate an N-terminal latency-associated peptide (LAP) and a C-terminal mature TGFβ Disulfide-linked homodimers of LAP and TGFβ remain non-covalently associated after secretion, forming the small latent TGFβ complex. Covalent linkage of LAP to latent TGFβ binding proteins create large latent complex that may interact with the extracellular matrix. Commercially available TGFβ proteins are produced as a recombinant protein expressed in CHO cells or as purified native protein from human platelets. Due to complex post-proteolytic modifications, TGFβ yield is low and the products are not available in economic bulk quantity. HumanZyme has developed an efficient human-cell based technology, HumaXpress™, for scalable production of human cytokines and produces TGFβ1, β2 and β3 (All HuXp™) from engineered human 293 cells. The proteins are highly purified disulfide-linked dimers of 25 kD that can be cost-effectively produced in large scale.

TH17 Polarization

TGFβ1, which are important for the polarization of murine TH17 cells, are reported not required, and are even inhibitory, for human Th17 polarization^1,2. In this study, whole CD4+ cells isolated from a healthy donor were stimulated with 10 µg/mL plate bound anti-CD3 and 10 µg/mL soluble anti-CD28 in the presence of Th17 polarizing cytokines from HumanZyme and another commercial vendor. After 5 days, supernatants were harvested for measurement of IL-17 by ELISA. The results show that all the TGFβ^HuXp are effective at inducing IL-17 secretion with optimal concentration of 0.1 ng/mL. In contrast, TGFβ1 from insect cells showed only marginal or even inhibitory effects. The results indicate that using biologically relevant cytokines can more effectively induce Th17 cell polarization and lead to a more accurate scientific understanding of the human biological process. A rapidly expanding range of HumaXpress™ cytokines are available from HumanZyme Inc. The proteins are manufactured to high quality standards and provide high biological activity, lot-to-lot consistency and low endotoxin levels. The specific products discussed here, TGFβ1^HuXp, TGFβ2^HuXp, TGFβ3^HuXp, IL-1 beta^HuXp, IL-6^HuXp, and IL-23^HuXp, are available in trial size and in bulk.