Effect of the passage frequency on macrophage capture by LeukoCatch. (A) Human macrophage (MONO-MAC-6) cells were subjected to serial passage (1, 2, 3, 4 or 5 times) of the same syringe (LeukoCatch system) with a stack of 5 filters. NT, non-treated. The bar graphs represent the number of macrophage cells (flow-through) that were not captured with the LeukoCatch system after serial passage. Cell numbers were counted by FACS (n = 4). (B) Western blot analysis with anti-GAPDH and anti-Erk1/2 antibodies using a 5-μL extract (10% of total) of cells that escaped from or were captured by the LeukoCatch filters, after being passed through the indicated number of times. (C) The bar graphs represent the relative intensity of the band signals measured by using the Image-J software, which were given as percentage of the starting material (NT: non-treated).