Literature > White Papers > Induction of Human Th17 Cells
Authentic HumanKine® IL-23 Expressed in Human Cells 100x More Potent For Induction of Human TH17 Cells
Cytokines are a group of proteins and polypeptides that organisms use as signaling molecules. Most cytokines are glycoproteins less than 30 kDa in size and bind to specific, high-affinity cell surface receptors. Due to their central role in the immune system, cytokines are involved in a variety of immunological, inflammatory and infectious diseases and widely used in research, diagnostics and therapeutics. Currently, these proteins are predominantly produced in non-human cells (e.g. E. coli, SF9, CHO) and therefore lack authenticity due to the absence of physiologically relevant glycosylation. In addition, a number of important cytokines are not commercially available due to inadequate proteolytic processing, protein folding or other post-translational modifications that occur in the non-human cell expression systems. HumanZyme has developed an efficient human-cell based technology, HumaXpress® for the scalable production of human cytokines. The company is expanding this range of tag-free produced cytokines, including difficult-to-express members of the TGFβ superfamily. HumanZyme’s authentic cytokines are preferred reagents for stem cell, cancer, inflammation research, and antibody development.
Currently, commercially available recombinant IL-23 cytokine is produced as a heterodimeric or fusion protein from an insect cell expression system. HumanZyme has produced HumanKine IL-23 in a stable cell culture of engineered human HEK293 cells. The protein is expressed as a disulfide-linked dimer of 55 kD and, due to the scalability of the stable culture, can be cost-effectively produced (Fig. 1).
IL-17 producing CD4+ T cells (Th17 cells) have been identified as a unique subset of T helper cells that develop along a pathway that is distinct from the Th1 and Th2-cell differentiation pathways. This finding has provided exciting new insights into immunoregulation, host defense and the pathogenesis of autoimmune diseases. Recently it has been shown that TGFß1, IL-1ß, IL-6, and IL-23 are important in driving human Th17 differentiation. The bioactivities of IL-23 from human and insect cells were first determined by the dose-dependent secretion of IL-17 from mouse splenocytes activated with 10 ng/ml PMA, which shows that HumanKine IL-23 is tenfold more active (Fig. 2). The activities were further assayed with human CD4+ cells which were isolated from a healthy donor and stimulated with 10 µg/ml plate bound anti-CD3 and 10 µg/ml soluble anti-CD28 in the presence of Th17 polarizing cytokines. After 5 days supernatants were harvested for measurement of IL-17 by ELISA. The results show that HumanKine IL-23 is 100-fold more potent for inducing IL-17 secretion in two independent studies; maximum induction was achieved with 0.1 ng/ml HumanKine IL-23 vs. 10 ng/ml with insect cell-produced IL-23 (Fig. 3). These results demonstrate that authentic human cell expressed cytokines can induce Th17 cell differentiation at physiologically relevant concentrations and may lead to a more accurate scientific understanding of the human biological process.
A rapidly expanding range of HumanKine cytokines are available from HumanZyme Inc. The proteins are manufactured to high quality standards and provide high biological activity, lot-lot-lot consistency and low endotoxin levels.