Anti-NKP46 antibodies, toxin conjugates, and therapeutic use of same

1. An antibody or antibody fragment that binds to NKp46 comprising at least the antigen recognition region, wherein the antigen recognition region comprises the complementarity determining region (CDR) amino acid sequences contained in a monoclonal antibody comprising heavy chain variable region set forth in SEQ ID NO: 2 and light chain variable region sequence set forth in SEQ ID NO: 10.

2. The antibody or antibody fragment according to claim 1 , comprising the CDR amino acid sequences set forth in heavy chain ordered N to C terminus: SEQ ID NOs: 4, 6 and 8, and light chain ordered N to C terminus: SEQ ID NOs: 12, 14 and 16.

3. The antibody of claim 1 , comprising a heavy chain variable region set forth in SEQ ID NO: 2 and a light chain variable region sequence set forth in SEQ ID NO: 10.

4. The antibody fragment of claim 1 selected from the group consisting of a Fab, F(ab′)2, Fv, scFv, dsFv and a single domain molecule.

5. The antibody or antibody fragment of claim 1 , wherein said antibody or antibody fragment is conjugated to a therapeutic moiety.

6. The antibody or antibody fragment of claim 5 , wherein said therapeutic moiety is selected from the group consisting of a cytotoxic moiety, a toxic moiety, a cytokine moiety, a drug and an immunotoxin.

7. The antibody or antibody fragment of claim 6 , wherein said toxic moiety is selected from the group consisting of Pseudomonas exotoxin, Diphtheria toxin, Ricin A toxin, Saporin toxin and Gelonin toxin.

8. The antibody or antibody fragment of claim 5 , wherein said therapeutic moiety is selected from the group consisting of Interleukin 2, Interleukin 4, Interleukin 10, CD3, CD16, and combinations thereof.

9. The antibody or antibody fragment of claim 6 , wherein said toxic moiety is a saporin toxin.

10. A pharmaceutical composition comprising as an active ingredient the antibody or antibody fragment of claim 1 , and a pharmaceutically acceptable carrier.

11. An antibody or antibody fragment drug conjugate comprising an antigen recognition region and a toxic moiety, wherein the antibody or antibody fragment drug conjugate comprising an antigen recognition region comprises heavy chain CDR amino acid sequences as set forth in SEQ ID NOs: 4, 6 and 8, and light chain CDR sequences set forth in SEQ ID NOs: 12, 14 and 16.

12. The antibody or antibody fragment drug conjugate of claim 11 , wherein said toxic moiety is a saporin toxin.

13. A pharmaceutical composition comprising as an active ingredient the antibody or antibody fragment drug conjugate of claim 11 , and a pharmaceutically acceptable carrier.

14. A method of eliminating a population of NK cells, comprising contacting a cell population of NK cells expressing NKp46 with the antibody or antibody fragment drug conjugate of claim 11 , wherein binding of said antibody or antibody fragment drug conjugate induces NKp46 internalization and killing.

15. A method of treating a cancer associated with expression of NKp46 in a subject in need thereof, the method comprising administering to the subject a therapeutically effective amount of the antibody or antibody fragment of claim 5 .

16. The method of claim 15 , wherein said cancer is a hematopoietic cancer.

17. The method of claim 15 , wherein the cancer is selected from the group consisting of an extranodal NK/T-cell lymphoma, a NK cell leukemia, a mycosis fungoides, an ALK+ anaplastic large cell lymphoma and a T-cell large granular lymphocyte (LGL) leukemia.

18. The method of claim 15 , further comprising treating said subject with an additional anti-cancer agent or therapy.

19. The method of claim 18 , wherein said anti-cancer agent or therapy is selected from the group consisting of a chemotherapeutic agent, an antibody immunotherapy, a radiation therapy, a surgery, a cancer vaccine, an anti-inflammatory agent and a dietary supplement.

20. The method of claim 15 , wherein said therapeutically effective amount results in reduction in the amount of cancerous cells in the subject following said administering.

21. An article of manufacture comprising the antibody or antibody fragment of claim 5 being packaged in a packaging material and identified in print, in or on said packaging material for use in the treatment of cancer associated with an expression of NKp46.

22. An isolated polynucleotide encoding the antibody or antibody fragment of claim 1 .

23. The isolated polynucleotide of claim 22 , wherein a nucleic acid sequence of said isolated polynucleotide is as set forth in heavy chain order N to C terminus SEQ ID NOs: 3, 5 and 7, and light chain order N to C terminus SEQ ID NOs: 11, 13 and 15.

24. The isolated polynucleotide of claim 22 encoding an antibody comprising a heavy chain variable region set forth in SEQ ID NO: 2 and a light chain variable region sequence set forth in SEQ ID NO: 10.

25. The isolated polynucleotide of claim 24 , wherein a nucleic acid sequence of said isolated polynucleotide is as set forth in SEQ ID NOs: 1 and 9.

26. The isolated polynucleotide of claim 22 encoding an antibody fragment selected from the group consisting of a Fab, F(ab′)2, Fv, scFv, dsFv and a single domain molecule.

27. An expression vector comprising the isolated polynucleotide of claim 22 .

28. A cell comprising the polynucleotide of claim 22 .

29. A method of detecting expression of NKp46 in a biological sample, the method comprising contacting said biological sample with the antibody or antibody fragment of claim 1 , and detecting binding between said antibody or antibody fragment and the NKp46, thereby detecting expression of said NKp46 in the biological sample.

30. The method of claim 29 , wherein the biological sample is from a subject diagnosed with cancer.

31. A method of diagnosing a disease associated with an expression of NKp46 in a subject, the method comprising: (a) contacting a biological sample from the subject with the antibody or antibody fragment of claim 1 , under conditions which allow the formation of immunocomplexes between NKp46 and said antibody or antibody fragment; and (b) determining a level of said immunocomplexes in said biological sample, wherein an increase in the level of said immunocomplexes above a predetermined threshold is indicative of the disease associated with the expression of NKp46, wherein the predetermined threshold is the level of said immunocomplexes in a biological sample from a healthy individual.

32. The method of claim 31 , wherein the disease associated with an expression of NKp46 is cancer.

33. A method of diagnosing and treating a cancer associated with an expression of NKp46 in a subject, the method comprising: (a) contacting a biological sample of the subject with the antibody of claim 1 , under conditions which allow the formation of immunocomplexes between NKp46 and said antibody or antibody fragment; and (b) detecting the level of NKp46 immunocomplexes in said biological sample; (c) diagnosing the subject with a cancer that is associated with an expression of NKp46 when an increase in the level of said immunocomplexes is higher than a predetermined threshold, where the predetermined threshold is the level of said immunocomplexes in a biological sample from a healthy individual; and (d) administering a therapeutic agent for the treatment of said cancer associated with an expression of NKp46 to the diagnosed subject, thereby diagnosing and treating the cancer associated with an expression of NKp46 in the subject.

34. The method of claim 33 , further comprising corroborating the diagnosis using a diagnostic assay selected from a blood test, an MRI or a CT scan.

35. A method of monitoring treatment of a subject having cancer associated with an expression of NKp46, the method comprising: (a) treating a subject in need thereof with a medicament for the treatment of a cancer associated with an expression of NKp46; and (b) detecting expression of NKp46 in a first biological sample of the subject prior to and second biological sample following said treatment, wherein said detecting comprises contacting the first and second biological samples with the antibody or antibody fragment of claim 1 , and detecting binding between said antibody or antibody fragment and the NKp46, wherein a lower expression level of NKp46 in the second biological sample following said treatment as compared to said expression level of NKp46 in the first biological sample prior to said treatment is indicative that the treatment is effective.

36. The method of claim 15 , wherein said subject is a human subject.

37. The antibody or antibody fragment of claim 1 , wherein the antibody is a monoclonal antibody.