Anti SEZ6 antibodies and methods of use

1. An isolated antibody or fragment thereof of, that specifically binds a human seizure related 6 homolog (SEZ6) protein, wherein said antibody or fragment thereof comprises:

(a) three CDRs of a light chain variable region of SEQ ID NO: 44 and three CDRs of a heavy chain variable region of SEQ ID NO: 45;

(b) three CDRs of a light chain variable region of SEQ ID NO: 48 and three CDRs of a heavy chain variable region of SEQ ID NO: 49;

(c) three CDRs of a light chain variable region of SEQ ID NO: 64 and three CDRs of a heavy chain variable region of SEQ ID NO: 65;

(d) three CDRs of a light chain variable region of SEQ ID NO: 68 and three CDRs of a heavy chain variable region of SEQ ID NO: 69;

(e) three CDRs of a light chain variable region of SEQ ID NO: 80 and three CDRs of a heavy chain variable region of SEQ ID NO: 81;

(f) three CDRs of a light chain variable region of SEQ ID NO: 116 and three CDRs of a heavy chain variable region of SEQ ID NO: 117;

(g) three CDRs of a light chain variable region of SEQ ID NO: 122 and three CDRs of a heavy chain variable region of SEQ ID NO: 123;

(h) three CDRs of a light chain variable region of SEQ ID NO: 130 and three CDRs of a heavy chain variable region of SEQ ID NO: 131;

(i) three CDRs of a light chain variable region of SEQ ID NO: 134 and three CDRs of a heavy chain variable region of SEQ ID NO: 135;

(j) three CDRs of a light chain variable region of SEQ ID NO: 138 and three CDRs of a heavy chain variable region of SEQ ID NO: 139;

(k) three CDRs of a light chain variable region of SEQ ID NO: 146 and three CDRs of a heavy chain variable region of SEQ ID NO: 147;

(I) three CDRs of a light chain variable region of SEQ ID NO: 150 and three CDRs of a heavy chain variable region of SEQ ID NO: 151;

(m) three CDRs of a light chain variable region of SEQ ID NO: 154 and three CDRs of a heavy chain variable region of SEQ ID NO: 155;

(n) three CDRs of a light chain variable region of SEQ ID NO: 158 and three CDRs of a heavy chain variable region of SEQ ID NO: 159;

(o) three CDRs of a light chain variable region of SEQ ID NO: 160 and three CDRs of a heavy chain variable region of SEQ ID NO: 161;

(p) three CDRs of a light chain variable region of SEQ ID NO: 162 and three CDRs of a heavy chain variable region of SEQ ID NO: 163;

(q) three CDRs of a light chain variable region of SEQ ID NO: 164 and three CDRs of a heavy chain variable region of SEQ ID NO: 165; and

(r) three CDRs of a light chain variable region of SEQ ID NO: 168 and three CDRs of a heavy chain variable region of SEQ ID NO: 169.

2. The antibody or fragment thereof of claim 1 comprising a V L and a V H , wherein the V L has three complementarity determining regions of SEQ ID NO: 168, and the V H has three complementarity determining regions of SEQ ID NO: 169.

3. The antibody or fragment thereof of claim 2 comprising residues 24-34 of SEQ ID NO: 168 for CDR-L1, residues 50-56 of SEQ ID NO: 168 for CDR-L2, residues 89-97 of SEQ ID NO: 168 for CDR-L3, residues 31-35 of SEQ ID NO: 169 for CDR-H1, residues 50-65 of SEQ ID NO: 169 for CDR-H2 and residues 95-102 of SEQ ID NO: 169 for CDR-H3, wherein the residues are numbered according to Kabat.

4. The antibody or fragment thereof of claim 2 , wherein the V L comprises SEQ ID NO: 190 and wherein the V H comprises SEQ ID NO: 191.

5. The isolated antibody or fragment thereof of claim 1 , wherein the antibody or fragment thereof comprises a monoclonal antibody.

6. The isolated antibody or fragment thereof of claim 5 , wherein the monoclonal antibody is selected from the group consisting of chimeric antibodies, humanized antibodies and human antibodies.

7. The isolated antibody or fragment thereof of claim 1 , wherein said antibody is conjugated to a cytotoxic agent.

8. The isolated antibody or fragment thereof of claim 7 , wherein the cytotoxic agent comprises a pyrrolobenzodiazepine (PBD).

9. The isolated antibody or fragment thereof of claim 7 , wherein the cytotoxic agent comprises an auristatin.

10. The isolated antibody or fragment thereof of claim 7 , wherein the cytotoxic agent comprises a maytansinoid.

11. The isolated antibody or fragment thereof of claim 7 , wherein the cytotoxic agent comprises a calicheamicin.

12. The isolated antibody or fragment thereof of claim 7 , wherein the cytotoxic agent comprises a radioisotope.