High-level production of biologically active chemokines in Escherichia coli

• Efficient soluble expression of chemokines in Escherichia coli has been obtained after optimization of expression conditions.
• A convenient chromatography method has been developed for efficient purification of recombinant chemokines.
• The biological activity of recombinant chemokines has been verified and CCL11 and CCL24 show similar binding affinity with CCR3.

The chemokines eotaxin-1 (CCL11) and eotaxin-2 (CCL24), belonging to the CC chemokines family, play key roles in the inflammatory response, allergic asthma and other diseases. When expressed in Escherichia coli, chemokines are prone to form inclusion bodies devoid of biological activity, and it is hard to refold them properly. Here an expression and purification protocol for high-level production of soluble and biologically active CCL11 and CCL24 in E. coli has been established. A final yield of 8.7 mg/l for CCL11 and 3.9 mg/l for CCL24 has been obtained and the purified proteins were characterized with SDS-PAGE, mass spectrometry and circular dichroism. High binding affinity of purified chemokines with CC chemokine receptor type 3 (CCR3) has been confirmed with surface plasmon resonance (SPR) and the KD values are 3.7 × 10−7 M and 3.0 × 10−7 M, respectively, for CCL11 and CCL24. This report provides a straightforward strategy for the efficient production of soluble and biologically active chemokines in E. coli.