Background: Chemokines and their cognate receptors play important role in the control of leukocyte chemotaxis,
HIV entry and other inflammatory diseases. Developing an effcient method to investigate the functional expression
of chemokines and its interactions with specific receptors will be helpful to asses the structural and functional
characteristics as well as the design of new approach to therapeutic intervention.
Results: By making systematic optimization study of expression conditions, soluble and functional production
of chemokine C-C motif ligand 8 (CCL8) in Escherichia coli (E. coli) has been achieved with approx. 1.5 mg
protein/l culture. Quartz crystal microbalance (QCM) analysis exhibited that the purified CCL8 could bind with
C-C chemokine receptor type 3 (CCR3) with dissociation equilibrium constant (KD) as 1.2 × 10−7 M in vitro.
Obvious internalization of CCR3 in vivo could be detected in 1 h when exposed to 100 nM of CCL8. Compared with
chemokine C-C motif ligand 11 (CCL11) and chemokine C-C motif ligand 24 (CCL24), a weaker chemotactic effect of
CCR3 expressing cells was observed when induced by CCL8 with same concentration.
Conclusion: This study delivers a simple and applicable way to produce functional chemokines in E. coli. The results
clearly confirms that CCL8 can interact with chemokine receptor CCR3, therefore, it is promising area to develop drugs
for the treatment of related diseases.

• Functional expression of CCL8 and its interaction with chemokine receptor CCR3