Mutated env sequence involved in the modulation of the immunosuppressive effect of viral proteins

1. An isolated mutated ENV protein resulting from mutation of a transmembrane subunit of a wild type viral ENV protein, the transmembrane subunit of said wild type viral ENV protein comprising an immunosuppressive domain comprising the following amino acid sequence:

(SEQ ID NO: 156)

NY 1 Y 2 Y 3 LY 4 Y 5 LY 6 Y 7 Y 8 X 1 Y 9 Y 10 Y 11 CY 12 X 2

wherein,

Y 1 is C or R,

Y 2 is R, M, L or Q,

Y 3 is C, G or A,

Y 4 is D,

Y 5 is L, M, Y or I,

Y 6 is F, T, L or M,

Y 7 is W, L or A,

Y 8 is E, K, Q, A or S,

Y 9 is G or E,

Y 10 is G,

Y 11 is L, I or V,

Y 12 is K, A, V, L, G, M or I,

X 1 is E, K or Q, and

X 2 is A, V, L, I, K or M, or

an isolated fragment of said mutated ENV protein, provided that said fragment comprises SEQ ID NO: 156,

wherein,

in the mutated ENV protein or fragment thereof, amino acid X 1 is substituted by R or H,

there is no substitution other than that of amino acid X 1 , and optionally also X 2 , and

said mutated ENV protein or fragment thereof has decreased immunosuppressive activity with respect to the wild type viral ENV protein.

2. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein the transmembrane subunit of said wild type viral ENV protein comprises an immunosuppressive domain comprising the following amino acid sequence:

(SEQ ID NO: 156)

NY 1 Y 2 Y 3 LY 4 Y 5 LY 6 Y 7 Y 8 X 1 Y 9 Y 10 Y 11 CY 12 X 2

wherein,

Y 1 is C or R,

Y 2 is R,

Y 3 is C or G,

Y 4 is D,

Y 5 is L or M,

Y 6 is F or T,

Y 7 is W, L or A,

Y 8 is E, K, Q, A or S,

Y 9 is G,

Y 10 is G,

Y 11 is L or I,

Y 12 is K, A, V or L,

X 1 is E, K or Q, and

X 2 is A.

3. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein amino acid X 1 is substituted by R or H and amino acid X 2 is substituted by F, M, Y or W.

4. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein the wild type viral ENV protein is:

a HERV ENV selected from the group consisting of:

HERV-FRD ENV as set forth in SEQ ID NO: 82,

HERV-T ENV as set forth in SEQ ID NO: 84,

HERV-R ENV as set forth in SEQ ID NO: 86,

HERV-V ENV as set forth in SEQ ID NO: 88, and

HERV-R(b) ENV as set forth in SEQ ID NO: 90, or

an ENV selected from the group consisting of:

HTLV-1 ENV as set forth in SEQ ID NO: 92,

HTLV-2 ENV as set forth in SEQ ID NO: 94,

PERV ENV as set forth in SEQ ID NO: 98,

STLV-1 ENV as set forth in SEQ ID NO: 100,

MoMLV ENV as set forth in SEQ ID NO: 70,

MPMV ENV as set forth in SEQ ID NO: 72, and

FV ENV as set forth in SEQ ID NO: 102.

5. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein the transmembrane subunit of said wild type viral ENV protein comprises an immunosuppressive domain comprising one of SEQ ID NO: 33, SEQ ID NO: 34, SEQ ID NO: 35, SEQ ID NO: 36, SEQ ID NO: 38 or SEQ ID NO: 39.

6. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein the transmembrane subunit of said mutated viral ENV protein comprises a mutated immunosuppressive domain comprising one of SEQ ID NO: 48, SEQ ID NO: 49, SEQ ID NO: 50, SEQ ID NO: 53 or SEQ ID NO: 54.

7. The isolated mutated ENV protein or fragment thereof according to claim 1 , wherein the amino acid sequence of the mutated ENV protein is selected from the group consisting of: SEQ ID NO: 120, SEQ ID NO: 124, SEQ ID NO: 128, SEQ ID NO: 146, SEQ ID NO: 108, SEQ ID NO: 112, and SEQ ID NO: 150.

8. The isolated mutated ENV protein or fragment thereof according to claim 3 , wherein the amino acid sequence of the mutated ENV protein is selected from the group consisting of: SEQ ID NO: 122, SEQ ID NO: 126, SEQ ID NO: 130, SEQ ID NO: 148, SEQ ID NO: 110, SEQ ID NO: 114, and SEQ ID NO: 152.

9. A pharmaceutical composition, comprising as active substance the mutated ENV protein as defined in claim 1 , in association with a pharmaceutically acceptable carrier.

10. An isolated mutated ENV protein resulting from mutation of a transmembrane subunit of a wild type viral ENV protein, or an isolated fragment of said mutated ENV protein,

said mutated ENV protein or fragment having a decreased immunosuppressive activity with respect to the wild type viral ENV protein,

the transmembrane subunit of said mutated ENV protein or isolated fragment thereof having a mutated immunosuppressive domain comprising SEQ ID NO: 43.

11. A pharmaceutical composition comprising as active substance the mutated ENV protein as defined in claim 10 , in association with a pharmaceutically acceptable carrier.

12. The isolated mutated ENV protein or fragment thereof according to claim 3 , wherein amino acid X 1 is substituted by R and amino acid X 2 is substituted by F.

13. An isolated protein, comprising the following amino acid sequence:

(SEQ ID NO: 156)

NY 1 Y 2 Y 3 LY 4 Y 5 LY 6 Y 7 Y 8 X 1 Y 9 Y 10 Y 11 CY 12 X 2

wherein,

Y 1 is C or R,

Y 2 is R, M, L or Q,

Y 3 is C, G or A,

Y 4 is D,

Y 5 is L, M, Y or I,

Y 6 is F, T, L or M,

Y 7 is W, L or A,

Y 8 is E, K, Q, A or S,

Y 9 is G or E,

Y 10 is G,

Y 11 is L, I or V,

Y 12 is K, A, V, L, G, M or I,

X 1 is R or H, and

X 2 is A, V, L, I, K, F, M, Y or W.

14. The isolated protein according to claim 13 , wherein:

Y 1 is C or R,

Y 2 is R,

Y 3 is C or G,

Y 4 is D,

Y 5 is L or M,

Y 6 is F or T,

Y 7 is W, L or A,

Y 8 is E, K, Q, A or S,

Y 9 is G,

Y 10 is G,

Y 11 is L or I,

Y 12 is K, A, V or L,

X 1 is R or H, and

X 2 is A, F, M, Y or W.

15. The isolated protein according to claim 14 , wherein X 2 is F, M, Y or W.

16. The isolated protein according to claim 14 , wherein X 1 is R and X 2 is F.

17. A pharmaceutical composition, comprising as active substance the protein as defined in claim 14 , in association with a pharmaceutically acceptable carrier.