Trail collectin fusion proteins

1. A fusion protein comprising:

(i) TRAIL (tumor necrosis factor-related apoptosis-inducing ligand) or a receptor binding domain thereof, and

(ii) a collectin trimerization domain comprising a neck domain or a neck and carbohydrate binding domain of surfactant protein-D,

wherein (ii) is located C-terminally of (i).

2. The fusion protein of claim 1 , additionally comprising a flexible linker between (i) and (ii), wherein the flexible linker is a glycine/serine linker and has a length of 3-20 amino acids.

3. The fusion protein of claim 2 , wherein the flexible linker element has the amino acid sequence of SEQ ID NO: 53, which is (GSS) a (SSG) b (GSG) c wherein a, b, c is each 0, 1, 2, 3, 4, 5 or 6.

4. The fusion protein of claim 2 , wherein the flexible linker element has a length of 9-15 amino acids.

5. The fusion protein of claim 1 , wherein the TRAIL has the sequence of SEQ ID NO:10.

6. The fusion protein of claim 1 , wherein (i) comprises amino acids 95-281, 116-281, 117-281, 118-281, 119-281 or 120-281 of human TRAIL (SEQ ID NO:10).

7. The fusion protein of claim 1 , wherein (i) comprises a mutant of SEQ ID NO:10 or a receptor binding domain thereof, which binds and/or activates TRAIL-receptor 1 and/or TRAIL-receptor 2, wherein the mutant comprises amino acid substitutions only in one or more of the following amino acid positions of SEQ ID NO:10: R130, G160, Y189, R191, Q193, E195, N199, K201, Y213, T214, 5215, H264, 1266, D267, and D269.

8. The fusion protein of claim 7 , wherein the amino acid substitutions are one or more of the following: R130E, G160M, Y189A, Y189Q, R191K, Q193S, Q193R, E195R, N199V, N199R, K201R, Y213W, T214R, S215D, H264R, 1266L, D267Q, D269H, D269R, and D269K.

9. The fusion protein of claim 1 , wherein (ii) comprises amino acids 217-375, 218-375, 219-375, 220-375, 221-375, 222-375, 223-375, 224-375, or 225-375 of human surfactant protein-D of SEQ ID NO:21.

10. The fusion protein of claim 1 , wherein (ii) comprises amino acids 217-257, 218-257, 219-257, 220-257, 221-257, 222-257, 223-257, 224-257, or 225-257 of human surfactant protein-D of SEQ ID NO:21.

11. The fusion protein of claim 1 , wherein (ii) comprises a mutant of human surfactant protein-D of SEQ ID NO:21 having only one amino acid substitution.

12. The fusion protein of claim 11 , wherein the amino acid substitution is one of the following: F355A, F355S, F355T, F355E, F355D, F355K, or F355R.

13. The fusion protein of claim 11 , wherein (ii) comprises a mutant which does not bind to mannose.

14. The fusion protein of claim 1 , which additionally comprises an N-terminal signal peptide domain.

15. The fusion protein of claim 1 , which comprises the sequence of SEQ ID NO: 43 or 44.

16. The fusion protein of claim 1 , wherein the fusion protein further comprises a recognition/purification domain located at the N-terminus or at the C-terminus.

17. The fusion protein of claim 16 , wherein the recognition/purification domain is a Strep-tag or a poly His-domain.

18. The fusion protein of claim 1 , which additionally comprises a terminal flexible element.

19. A trimeric complex comprising three fusion proteins of claim 1 .

20. The trimeric complex of claim 19 , wherein the complex is formed by covalent linkage between the three fusion proteins.

21. The trimeric complex of claim 19 , wherein the complex consists of three identical fusion proteins.

22. A nucleic acid molecule encoding the fusion protein of claim 1 .

23. The nucleic acid molecule of claim 22 , which is operatively linked to an expression control sequence.

24. A vector comprising the nucleic acid molecule of claim 23 .

25. An isolated cell transformed or transfected with the nucleic acid molecule of claim 23 .