A conjugate of a potent cytotoxic agent with a cell-surface receptor bindingmoleculehaving a structure represented by Formula (I), wherein T, L, m, n, -----, R1,R2, R3, R4, R5, R6,R7, R8, R9, R10, R11, R12, and R13 are as defined herein, can be used fortargeted treatment ofcancer, autoimmune disease, and infectious disease.(see formula I)