Macrophage Inflammatory Protein 3 Beta (MIP3b) is a small cytokine belonging to the CC chemokine family that is also known as EBI1 ligand chemokine (ELC) and Chemokine C-C motif ligand 19 (CCL19). This chemokine elicits its effects on its target cells by binding to the chemokine receptor 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 MIP3b on the Jurkat cell line. Briefly, Jurkat cells were seeded into the upper chambers (150μL cell suspension,106 cells/mL in RPMI 1640 with FBS free) and MIP3b (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 (8μm pore size) used to separate the two compartments. After incubation at 37℃ with 5% CO2 for 3h, 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 MIP3b 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 MIP3b occurs at 0.1-1ng/mL.
(A) Jurkat cells were seeded into the upper chambers and serum free RPMI 1640 with 0.1ng/mL MIP3b was added in lower chamber, then cells in lower chamber were observed at low magnification (×100) after incubation for 3h;
(B) Jurkat cells were seeded into the upper chambers and serum free RPMI 1640 without MIP3b was added in lower chamber, then cells in lower chamber were observed at low magnification (×100) after incubation for 3h.
Figure. The chemotactic effect of recombinant human MIP3b on Jurkat cells.

Figure. The chemotactic effect of recombinant human MIP3b on Jurkat cells.