A cytotoxicity assay was performed by incubating LL/2 cells with recombinant Blp1 C-terminal fragment in DMEM supplemented with 10% FBS at 37 °C for 24 h. Then, 20 μl of MTS (Promega) solution was added to the wells and cells were incubated for 4 h at 37 °C. After incubation, OD490 was determined. The proliferation rate was counted by comparing OD490 values for Blp1 C-terminus fragment-treated and non-treated cells.