Chemokines are proteins that induce tissue extravasation, promote differentiation, and induce chemotaxis. Because of these properties, the chemokine’s role in antitumor immune response is of great interest to researchers. The CXCL9,10,11/CXCR3 axis is specific in that it regulates immune cell migration, differentiation, and activation, leading to tumor suppression. CXCL9 mainly mediates lymphatic infiltration to the focal sites and suppresses tumor growth. In this research, we expressed the novel CXCL9 protein within competent BL21 cells. Two variations of a pET22b plasmid were used, one with PelB (to cleave initial methionine on protein sequence) and one without. It was found that after induction, CXCL9 was expressed without the PelB leader sequence. From here we purified the CXCL9 protein and deduced that the overall expression of the protein was more than favorable. After isolating and concentrating the protein, a final concentration of 92 mg/ml was determined. With the purified protein, X-ray crystallographic studies will be used to determine the 3-D structure of the protein. This interface is important because it will impact the interaction with the receptor; therefore, altering the CXCL9/CXCR3 axis
