LIBS expression of 24/12 (the left row) and AM-1 cells (the right row). Cells were preincubated with 5 μmol/L FK633 (solid lines) or buffer (bold lines) for 30 minutes on ice, and then 5 μg/mL of LIBS1 (upper row), LIBS6 (middle row), or AP5 (lower row) was added. After 30 minutes of incubation, cells were washed and then incubated with FITC-conjugated antimouse IgG for 30 minutes. After washing, flow cytometric analysis was performed. Dotted lines indicate MOPC21, a control mouse IgG antibody, binding.