CD8-specific antibody constructs and compositions thereof

1 . An antibody or antigen binding fragment thereof that binds CD8, comprising a heavy chain variable region (V H ), and a light chain variable region (V L ), wherein the heavy chain variable region comprises three heavy chain complementarity determining regions (HCDR1, HCDR2, and HCDR3), and the light chain variable region comprises three light chain complementarity determining regions (LCDR1, LCDR2, and LCDR3), wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3, respectively, comprise:

a) SEQ ID NOs: 1, 70, 148, 240, 294, and 333, respectively;

b) SEQ ID NOs: 2, 71, 149, 241, 294, and 334, respectively;

c) SEQ ID NOs: 3, 72, 148, 240, 294, and 333, respectively;

d) SEQ ID NOs: 4, 73, 649, 242, 295, and 335, respectively;

e) SEQ ID NOs: 5, 74, 150, 242, 295, and 336, respectively;

f) SEQ ID NOs: 6, 75, 151, 243, 296, and 337, respectively;

g) SEQ ID NOs: 7, 76, 152, 244, 295, and 338, respectively;

h) SEQ ID NOs: 8, 77, 153, 244, 297, and 339, respectively;

i) SEQ ID NOs: 9, 77, 154, 245, 298, and 340, respectively;

j) SEQ ID NOs: 10, 78, 650, 246, 297, and 341, respectively;

k) SEQ ID NOs: 11, 79, 155, 247, 299, and 342, respectively;

l) SEQ ID NOs: 12, 80, 156, 248, 300, and 343, respectively;

m) SEQ ID NOs: 13, 81, 157, 249, 294, and 344, respectively;

n) SEQ ID NOs: 14, 76, 158, 242, 295, and 345, respectively;

o) SEQ ID NOs: 15, 76, 159, 250, 301, and 346, respectively;

p) SEQ ID NOs: 11, 82, 160, 249, 294, and 347, respectively;

q) SEQ ID NOs: 16, 83, 161, 251, 302, and 340, respectively;

r) SEQ ID NOs: 17, 84, 162, 241, 303, and 348, respectively;

s) SEQ ID NOs: 18, 85, 163, 252, 304, and 349, respectively;

t) SEQ ID NOs: 19, 86, 164, 241, 305, and 350, respectively;

u) SEQ ID NOs: 20, 87, 165, 253, 299, and 351, respectively;

v) SEQ ID NOs: 4, 88, 166, 249, 299, and 352, respectively;

w) SEQ ID NOs: 21, 89, 167, 242, 306, and 353, respectively;

x) SEQ ID NOs: 22, 90, 168, 241, 307, and 354, respectively;

y) SEQ ID NOs: 23, 91, 169, 241, 299, and 355, respectively;

z) SEQ ID NOs: 24, 92, 170, 241, 299, and 356, respectively;

aa) SEQ ID NOs: 25, 93, 171, 254, 308, and 344, respectively;

bb) SEQ ID NOs: 26, 94, 172, 240, 294, and 333, respectively;

cc) SEQ ID NOs: 26, 94, 172, 240, 294, and 333, respectively;

dd) SEQ ID NOs: 1, 79, 174, 255, 294, and 358, respectively;

ee) SEQ ID NOs: 28, 95, 175, 256, 294, and 359, respectively;

ff) SEQ ID NOs: 29, 79, 176, 257, 309, and 360, respectively;

gg) SEQ ID NOs: 1, 96, 177, 240, 294, and 333, respectively;

hh) SEQ ID NOs: 20, 97, 149, 251, 299, and 361, respectively;

ii) SEQ ID NOs: 30, 98, 178, 241, 310, and 362, respectively;

jj) SEQ ID NOs: 31, 99, 179, 240, 311, and 363, respectively;

kk) SEQ ID NOs: 32, 100, 180, 258, 312, and 364, respectively;

ll) SEQ ID NOs: 19, 101, 181, 259, 313, and 333, respectively;

mm) SEQ ID NOs: 33, 102, 182, 242, 314, and 365, respectively;

nn) SEQ ID NOs: 34, 103, 183, 260, 315, and 366, respectively;

oo) SEQ ID NOs: 35, 104, 184, 241, 302, and 367, respectively;

pp) SEQ ID NOs: 36, 105, 185, 261, 316, and 368, respectively;

qq) SEQ ID NOs: 37, 106, 186, 262, 294, and 369, respectively;

rr) SEQ ID NOs: 38, 107, 187, 263, 294, and 344, respectively;

ss) SEQ ID NOs: 39, 108, 188, 264, 317, and 344, respectively;

tt) SEQ ID NOs: 40, 109, 189, 240, 294, and 370, respectively;

uu) SEQ ID NOs: 8, 110, 190, 265, 299, and 371, respectively;

vv) SEQ ID NOs: 41, 111, 191, 266, 299, and 346, respectively;

ww) SEQ ID NOs: 19, 112, 192, 242, 318, and 372, respectively;

XX) SEQ ID NOs: 4, 113, 193, 267, 309, and 373, respectively;

yy) SEQ ID NOs: 4, 114, 194, 268, 302, 344, and 453, respectively;

zz) SEQ ID NOs: 42, 115, 195, 269, 319, 374, and 454, respectively;

aaa) SEQ ID NOs: 43, 77, 196, 270, 320, and 375, respectively;

bbb) SEQ ID NOs: 44, 116, 197, 271, 299, and 376, respectively;

ccc) SEQ ID NOs: 40, 117, 198, 272, 302, and 377, respectively;

ddd) SEQ ID NOs: 40, 118, 199, 259, 302, and 378, respectively;

eee) SEQ ID NOs: 45, 114, 200, 273, 321, and 379, respectively;

fff) SEQ ID NOs: 46, 119, 201, 240, 322, and 380, respectively;

ggg) SEQ ID NOs: 47, 120, 202, 274, 309, and 333, respectively;

hhh) SEQ ID NOs: 48, 121, 203, 252, 302, and 333, respectively;

iii) SEQ ID NOs: 49, 122, 204, 275, 311, and 381, respectively;

jjj) SEQ ID NOs: 44, 123, 205, 276, 311, and 333, respectively;

kkk) SEQ ID NOs: 50, 124, 206, 277, 299, and 382, respectively;

lll) SEQ ID NOs: 51, 77, 207, 278, 294, and 383, respectively;

mmm) SEQ ID NOs: 52, 125, 208, 240, 323, and 384, respectively;

nnn) SEQ ID NOs: 34, 126, 209, 279, 324, and 385, respectively;

ooo) SEQ ID NOs: 53, 127, 210, 280, 294, and 386, respectively;

ppp) SEQ ID NOs: 54, 128, 211, 281, 294, and 387, respectively;

qqq) SEQ ID NOs: 19, 129, 212, 282, 317, and 342, respectively;

rrr) SEQ ID NOs: 19, 130, 213, 242, 295, and 388, respectively;

sss) SEQ ID NOs: 55, 77, 214, 240, 325, and 389, respectively;

ttt) SEQ ID NOs: 8, 77, 215, 241, 326, and 390, respectively;

uuu) SEQ ID NOs: 56, 131, 216, 283, 294, and 344, respectively;

vvv) SEQ ID NOs: 57, 132, 217, 249, 327, and 333, respectively;

www) SEQ ID NOs: 19, 133, 218, 284, 297, and 391, respectively;

XXX) SEQ ID NOs: 58, 79, 219, 240, 294, and 333, respectively;

yyy) SEQ ID NOs: 19, 95, 220, 285, 299, and 342, respectively;

zzz) SEQ ID NOs: 58, 134, 221, 286, 294, and 392, respectively;

aaaa) SEQ ID NOs: 40, 93, 222, 241, 309, and 393, respectively;

bbbb) SEQ ID NOs: 59, 135, 223, 275, 299, and 344, respectively;

cccc) SEQ ID NOs: 19, 136, 224, 287, 302, and 394, respectively;

dddd) SEQ ID NOs: 60, 137, 225, 288, 309, and 333, respectively;

eeee) SEQ ID NOs: 10, 138, 226, 289, 328, and 395, respectively;

ffff) SEQ ID NOs: 19, 139, 227, 241, 329, and 396, respectively;

gggg) SEQ ID NOs: 1, 140, 228, 241, 294, and 397, respectively;

hhhh) SEQ ID NOs: 61, 141, 229, 241, 328, and 395, respectively;

iiii) SEQ ID NOs: 62, 93, 230, 241, 316, and 362, respectively;

jjjj) SEQ ID NOs: 63, 142, 231, 249, 330, 361, and 490, respectively;

kkkk) SEQ ID NOs: 64, 143, 232, 290, 299, and 399, respectively;

IIII) SEQ ID NOs: 65, 79, 233, 241, 331, and 400, respectively;

mmmm) SEQ ID NOs: 66, 79, 234, 241, 299, and 401, respectively;

nnnn) SEQ ID NOs: 19, 144, 235, 241, 332, and 371, respectively;

oooo) SEQ ID NOs: 67, 145, 236, 291, 330, and 402, respectively;

pppp) SEQ ID NOs: 19, 146, 237, 292, 294, and 344, respectively;

qqqq) SEQ ID NOs: 68, 147, 238, 241, 299, and 403, respectively; or

rrrr) SEQ ID NOs: 69, 77, 239, 293, 299, and 404, respectively.

2 . The antibody or antigen binding fragment thereof of claim 1 , comprising a heavy chain variable region (V H ) having an amino acid sequence with at least 90% identity to a sequence selected from SEQ ID NOs: 405-498.

3 . The antibody or antigen binding fragment thereof of claim 1 , comprising a light chain variable region (V L ) having an amino acid sequence with at least 90% identity to a sequence selected from SEQ ID NOs: 499-591.

4 . The antibody or antigen binding fragment thereof of claim 2 , comprising a V H having an amino acid sequence with at least 90% identity to a sequence selected from SEQ ID NOs: 405-498 and a V L having an amino acid sequence with at least 90% identity to a sequence selected from SEQ ID NOs: 499-591.

5 . The antibody or antigen binding fragment thereof of claim 2 , wherein the V H is selected from SEQ ID NOs: 405, 408, 448, and 455, and the V L is selected from 499, 503, 542, and 549.

6 . The antibody or antigen binding fragment thereof of claim 1 , wherein the HCDR1, HCDR2, HCDR3, LCDR1, LCDR2, and LCDR3, respectively, comprise:

a) SEQ ID NOs: 1, 70, 148, 240, 294, 333, respectively;

b) SEQ ID NOs: 5, 74, 150, 242, 295, 336, respectively;

c) SEQ ID NOs: 40, 109, 189, 240, 294, 370, respectively; or

d) SEQ ID NOs: 43, 77, 196, 270, 320, 375, respectively.

7 . The antibody or antigen binding fragment thereof of claim 1 , which binds to human CD8α or CD8β.

8 . The antibody or antigen binding fragment thereof of claim 1 , which binds to a human CD8α homodimer composed of two α chains.

9 . The antibody or antigen binding fragment thereof of claim 1 , which binds to a human CD8 heterodimer composed of one α chain and one β chain.

10 . The antibody or antigen binding fragment thereof of claim 1 ,

wherein the antigen binding fragment is a Fab, Fab′, F(ab′)2, scFv, (scFv)2, scFv-Fc, or Fv fragment.

11 . The antibody or antigen binding fragment thereof of claim 10 , wherein the antigen binding fragment is a scFv.

12 . The antibody or antigen binding fragment thereof of claim 11 , wherein the V H is on the N-terminal side of the V L .

13 . The antibody or antigen binding fragment thereof of claim 11 , wherein the V L is on the N-terminal side of the V H .

14 . The antibody or antigen binding fragment thereof of claim 11 , wherein the scFv comprises a linker connecting the V H and V L .

15 . The antibody or antigen binding fragment thereof of claim 14 , wherein the linker comprises the amino acid sequence set forth in SEQ ID NOs: 625-627 and 645-648.

16 . The antibody or antigen binding fragment thereof of claim 1 , which binds to human CD8α or human CD8β with a K D of about 400 nM or lower.

17 . The antibody or antigen binding fragment thereof of claim 1 , which binds to M. nemestrina CD8α or M. nemestrina CD8β with a K D of about 5 nM to about 500 nM.

18 . The antibody or antigen binding fragment thereof of claim 1 , which binds to human CD8α or CD8β with a K D of about 5 nM to about 500 nM.

19 . An isolated polynucleotide encoding the antibody or antigen binding fragment thereof of claim 1 .

20 . An isolated vector comprising the polynucleotide of claim 19 .

21 . An isolated host cell comprising the polynucleotide of claim 19 .