A modified human anti-factor B antibody or an antigen binding fragment thereof that selectively binds to factor B in the third domain of short consensus repeats ("SCR") and prevents the formation of the C3bBb complex, in which the modified human antibody or the antigen-binding fragment thereof has an equilibrium dissociation constant ("KD") between 3.0x10-9 M and 7.0x10-9 M, and in which: (a) the Modified human anti-factor B antibody or the antigen binding fragment thereof comprises a VH region polypeptide selected from the group consisting of SEQ ID NO: 14, SEQ 10 NO: 16, SEQ ID NO: 18, and SEQ ID No.: 20, and a VH region polypeptide selected from the group consisting of SEQ ID No.: 15, SEQ ID No.: 17, SEQ ID No.: 35, SEQ ID No.: 19, SEQ ID No.: 36, SEQ ID No. : 21 and SEQ ID NO: 37； or (b) the modified human anti-factor B antibody or an antigen binding fragment thereof comprises a VH region polypeptide comprising the CDR3-FR4 region selected from the group consisting of SEQ ID NO: 22, SEQ ID NO. : 24, SEQ ID No.: 26 and SEQ ID No.: 28, and a VH region polypeptide comprising the CDR3-FR4 region selected from the group consisting of SEQ ID No.: 23, SEQ ID No.: 25, SEQ ID No. : 27, and SEQ ID NO: 29.Un anticuerpo anti-factor B humano modificado o un fragmento de unión al antígeno del mismo que se une de manera selectiva al factor B en el tercer dominio de repeticiones consenso cortas ("SCR") e impide la formación del complejo C3bBb, en el que el anticuerpo humano modificado o el fragmento de unión al antígeno del mismo tiene una constante de disociación en equilibrio ("KD") de entre 3,0x10-9 M y 7,0x10-9 M, y en el que: (a) el anticuerpo anti-factor B humano modificado o el fragmento de unión al antígeno del mismo comprende un polipéptido de la región VH seleccionado del grupo que consiste en SEQ ID Nº:14, SEQ 10 NO:16, SEQ ID Nº:18, y SEQ ID Nº:20, y un polipéptido de la región VH seleccionado del grupo que consiste en SEQ ID Nº:15, SEQ ID Nº:17, SEQ ID Nº:35, SEQ I
