Refers to a single Chain of a Humanized monoclonal antibody that binds to a Protein with a KD of complement C3b or less 250pm comprising: (i) a heavy chain comprises: (a) a selected CDR1 with SEQ ID no: 1, 15, 29, 43, 57, 71, 85 99, 104, 127 141, 155, 169,18 3, 7, 21, 35, 49, 63, 77, 90, 105, 120, 140, 147, 154,175, 189 (b) a selected CDR2 of SEQ ID no: 2, 16, 30, 44, 58, 72, 86, 100, 112, 128, 156, 142, 170 and 184 (c) a selected CDr3 of SEQ No: 3, 17, 31, 45, 59, 73 87, 101, 115, 129, 143, 157 171 and 185 and (ii) a light chain comprises: (a) a selected CDR1 of SEQ ID Nos: 4, 18, 32, 46, 60, 74, 87, 102, 122, 130, 132, 158, 172, 186 and 8, 22, 36, 50, 64, 78, 95, 106, 120,134, 148, 162, 177, 190 (b) a selected CDR2 SEQ No: 5, 19, 33, 47, 61, 75, 89, 109, 117, 131, 145, 170, 173 and 187 (c) a selected CDr3 of SEQ ID no: 6, 20, 34, 48, 62, 76, 90, 104, 110, 143, 146, 160, 174, 188.Also refers to a Pharmaceutical composition containing Said monoclonal antibody that Inhibits the alternative Pathway of complement, and is useful in the treatment of macular degenerationSE REFIERE A UN ANTICUERPO MONOCLONAL HUMANIZADO DE UNA SOLA CADENA QUE SE ENLAZA A UNA PROTEINA DE COMPLEMENTO C3b CON UNA KD MENOR O IGUAL A 250PM QUE COMPRENDE: (I)UNA CADENA PESADA COMPRENDE: (A) UNA CDR1 CON SELECCIONADA DE SEQ ID NºS: 1, 15, 29, 43, 57, 71, 85, 99, 113, 127, 141, 155, 169,183 Y 7, 21, 35, 49, 63, 77, 91, 105, 119, 133, 147, 161, 175 Y 189 (B) UNA CDR2 SELECCIONADAS DE SEQ ID NºS: 2, 16, 30, 44, 58, 72, 86, 100, 114, 128, 142, 156, 170 Y 184 (C) UNA CDR3 SELECCIONADAS DE SEQ NºS: 3, 17, 31, 45, 59, 73, 87, 101, 115, 129, 143, 157, 171 Y 185 Y (II) UNA CADENA LIGERA COMPRENDE: (A) UNA CDR1 SELECCIONADAS DE SEQ ID NºS: 4, 18, 32, 46, 60, 74, 88, 102, 116, 130, 144, 158, 172, 186 Y 8, 22, 36, 50, 64, 78, 92, 106, 120, 134, 148, 162, 176 Y 190 (B) UNA CDR2 SELECCIONADAS DE SEQ NºS: 5, 19, 33, 47, 61, 75, 89, 103, 117, 131, 145, 159, 173 Y 187 (C) UNA CDR3 SELECCIONADAS DE SEQ ID NºS: 6, 2