The mAb Ad20, mouse IgM, that binds to CD99 at a distant region, and which was compared with the mAb 0662, could rapidly induce apoptosis in T-ALL cell lines, Jurkat and MOLT-4, but had no effects on the SUPT-1 (T-LBL) cell line and normal T cells [13]. Here, CD99 is linked to acute lymphoblastic leukemia.