Crosslinking of IFITM1 induces the expression of MMP-9 and IL-8 in THP-1 cells. (a) cells were stimulated with 1 μg/mL of LPS, 0.1, 1, 5, or 10 μg/mL of anti-IFITM1 or 10 μg/mL of isotype matching mouse IgG. Culture supernatants were collected in 24 hr for the measurement of MMP-9 activity using gelatin zymogram. (b) cells were stimulated with 1 μg/mL of LPS, 10 μg/mL of anti-IFITM1 or isotype matching mouse IgG. HI: heat inactivation, 95°C for 2 hr. (c) cells were stimulated with 1 μg/mL of LPS, 0.1, 1, 5, 10, or 30 μg/mL of anti-IFITM1 or 30 μg/mL of isotype matching mouse IgG. Culture supernatants were collected in 24 hr for the measurement of IL-8 concentration using ELISA. (d) and (e) cells were stimulated with 1 μg/mL of LPS (L), 30 μg/mL of anti-IFITM1 (I) or 30 μg/mL of isotype matching mouse IgG (M). Culture supernatants were collected in 24 hr for the measurement of MCP-1 (d) and TNF-α (e) concentrations using ELISA. C: control. These experiments were repeated more than three times with essentially the same results.