An anti-human CTLA-4 antibody, or antigen binding fragment thereof, comprising heavy chain variable region sequence and light chain variable region sequence pairs selected from the group consisting of: a) residues 1-118 of SEQ ID NO: 15 and residues 1-108 of SEQ ID NO: 21 (1pi. 1); b) residues 1-118 of SEQ ID NOs: 16 and residues 1-108 of SEQ ID NO: 21 (ipi.2); c) residues 1-118 of SEQ ID NOs: 17 and residues 1-108 of SEQ ID NO: 21 (ipi.3); d) residues 1-118 of SEQ ID NOs: 18 and residues 1-108 of SEQ ID NO: 21 (ipi.7); e) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 24 (ipi.17); f) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 25 (ipi.18); g) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 26 (ipi.20); h) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 29 (ipi.23); i) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 30 (ipi.24); j) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 22 (ipi.25); k) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 27 (ipi.26); l) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 21 (ipi.57); m) residues 1-118 of SEQ ID NOs: 19 and residues 1-108 of SEQ ID NO: 21 (ipi.59); n) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 22 (ipi.64); o) residues 1-118 of SEQ ID NOs: 19 and residues 1-108 of SEQ ID NO: 22 (ipi.66); p) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 21 (ipi.69); q) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 22 (ipi.71); r) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 21 (ipi.82); s) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 21 (ipi.84); t) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 22 (ipi.86); u) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 22 (ipi.88); v) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 23 (ipi.90); w) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 23 (ipi.92); x) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 23 (ipi.93); y) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 23 (ipi.94); z) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 23 (ipi.95); aa) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 27 (ipi.100); bb) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 27 (ipi.101); cc) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 28 (ipi.105); and dd) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 28 (ipi.106). a) residues 1-118 of SEQ ID NO: 15 and residues 1-108 of SEQ ID NO: 21 (1pi. 1); b) residues 1-118 of SEQ ID NOs: 16 and residues 1-108 of SEQ ID NO: 21 (ipi.2); c) residues 1-118 of SEQ ID NOs: 17 and residues 1-108 of SEQ ID NO: 21 (ipi.3); d) residues 1-118 of SEQ ID NOs: 18 and residues 1-108 of SEQ ID NO: 21 (ipi.7); e) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 24 (ipi.17); f) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 25 (ipi.18); g) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 26 (ipi.20); h) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 29 (ipi.23); i) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 30 (ipi.24); j) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 22 (ipi.25); k) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 27 (ipi.26); l) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 21 (ipi.57); m) residues 1-118 of SEQ ID NOs: 19 and residues 1-108 of SEQ ID NO: 21 (ipi.59); n) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 22 (ipi.64); o) residues 1-118 of SEQ ID NOs: 19 and residues 1-108 of SEQ ID NO: 22 (ipi.66); p) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 21 (ipi.69); q) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 22 (ipi.71); r) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 21 (ipi.82); s) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 21 (ipi.84); t) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 22 (ipi.86); u) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 22 (ipi.88); v) residues 1-118 of SEQ ID NOs: 20 and residues 1-108 of SEQ ID NO: 23 (ipi.90); w) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 23 (ipi.92); x) residues 1-118 of SEQ ID NOs: 11 and residues 1-108 of SEQ ID NO: 23 (ipi.93); y) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 23 (ipi.94); z) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 23 (ipi.95); aa) residues 1-118 of SEQ ID NOs: 12 and residues 1-108 of SEQ ID NO: 27 (ipi.100); bb) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 27 (ipi.101); cc) residues 1-118 of SEQ ID NOs: 13 and residues 1-108 of SEQ ID NO: 28 (ipi.105); and dd) residues 1-118 of SEQ ID NOs: 14 and residues 1-108 of SEQ ID NO: 28 (ipi.106).