Macrophage Inflammatory Protein 3 Alpha (MIP-3α), also known as LARC (liver and activation-regulated chemokine), Exodus-1 or CCL20, is a CC chemokine with a selective chemotactic activity for lymphocytes and dendritic cells (DCs). MIP3α is produced by activated cells, including monocytes, T cells, endothelial cells, epithelial cells, and fibroblasts and is expressed in liver, lung, and some lymphoid tissues. This chemokine elicits its effects on its target cells by binding to the chemokine receptor CCR7. It attracts certain cells of the immune system, including dendritic cells and antigen-engaged B cells, CCR7 central-memory T-Cells. Thus, chemotaxis assay used 24-well microchemotaxis system was undertaken to detect the chemotactic effect of recombinant human MIP-3α on the Jurkat cell line. Briefly, Jurkat cells were seeded into the upper chambers (200μL cell suspension,106 cells/mL in RPMI 1640 with FBS free) and MIP-3α (0.01ng/mL, 0.1ng/mL, 1ng/mL, 10ng/mL,100ng/mL and 1000ng/mL diluted separately in serum free RPMI 1640 ) was added in lower chamber with a polycarbonate filter (8 μm pore size) used to separate the two compartments. After incubation at 37℃ with 5% CO2 for 2h, the filter was removed, then cells in low chamber were observed by inverted microscope at low magnification (×100) and the number of migrated cells were counted at high magnification (×400) randomly (five fields for each filter). Result shows MIP-3α is able to induce migration of Jurkat cells. The migrated Jurkat cells in low chamber at low magnification (×100) were shown in Figure 1. Five fields of each chamber were randomly chosen, and the migrated cells were counted at high magnification (×400). Statistical results were shown in Figure 2. The optimum chemotaxis of recombinant human MIP-3α occurs at 1-10ng/mL.

Figure 2. The chemotactic effect of recombinant human MIP-3α on Jurkat cells