Heterobifunctional linkers with polyethylene glycol segments and immune response modifier conjugates made therefrom
Conjugates of an immune response modifier, a linker, and an antigen are disclosed. The linker is represented by formula: wherein A is CH or N, p is in a range from 1 to 50, R″ is a bond or -alkylene-O—, R′ is alkylene that is optionally interrupted or terminated with one or more amide or ether groups, and E is an amine- or thiol-reactive group. Pharmaceutical compositions containing the compound or the conjugate, methods of making a conjugate, and methods of use of the compounds or conjugates as immunomodulators for inducing cytokine biosynthesis in an animal and for vaccinating an animal are also disclosed. An antigen modified by the linker is also disclosed.
1. A conjugate comprising a reaction product of:
a hydrazine- or hydrazide-substituted immune response modifier;
a linker represented by formula:
wherein A is CH or N, p is in a range from 1 to 50, R″ is a bond or -alkylene-O—, R′ is alkylene that is optionally interrupted or terminated with one or more amide or ether groups, and E is an amine- or thiol-reactive group; and
an antigen,
wherein the immune response modifier comprises a 2-aminopyridine ring fused to a five-membered nitrogen-containing heterocyclic ring or a 4-aminopyrimidine ring fused to a five-membered nitrogen-containing heterocyclic ring.
2. The conjugate of claim 1 , wherein the hydrazine- or hydrazide-substituted immune response modifier is hydrazine-substituted and comprises an aromatic ring to which the hydrazine is bonded.
3. The conjugate of claim 1 , wherein E is selected from the group consisting of maleimide, vinylsulfone, acrylamide, pyridyldisulfide, methyl sulfonyl disulfide, N-hydroxysuccinimide ester, sulfo-N-hydroxysuccinimide ester or a salt thereof, 4-nitrophenyl ester, acid chloride, acid bromide, acid anhydride, pentafluorophenyl ester, tetrafluorophenyl ester, N-hydroxybenzotriazole ester, iodoacetyl, bromoacetyl, chloroacetyl, succinimidyl carbonate, chloroformate, —OC(O)—O—CH(Cl)CCl 3 , —OC(O)—O-(4-nitrophenyl), isocyanate, and thioisocyanate.
4. The conjugate of claim 3 , wherein R′ is alkylene having up to four carbon atoms, and E is an ester selected from the group consisting of N-hydroxysuccinimide ester, sulfo-N-hydroxysuccinimide ester or a salt thereof, 4-nitrophenyl ester, pentafluorophenyl ester, tetrafluorophenyl ester, and N-hydroxybenzotriazole ester.
5. The conjugate of claim 1 , wherein the antigen is a protein.
6. The conjugate of claim 5 , wherein a ratio of the linker to the protein is in a range from 30:1 to 1:3.
7. The conjugate of claim 1 , wherein the antigen is a vaccine.
8. The conjugate of claim 1 , wherein the hydrazine- or hydrazide-substituted immune response modifier is an imidazoquinoline amine, imidazonaphthyridine amine, pyrazoloquinoline amine, or pyrazolonaphthyridine amine, and wherein the hydrazine- or hydrazide is located at the 1-position or the 7-position of the imidazoquinoline amine, imidazonaphthyridine amine, pyrazoloquinoline amine, or pyrazolonaphthyridine amine.
9. The conjugate of claim 1 , wherein p is in a range from 2 to 16.
10. A pharmaceutical composition comprising a pharmaceutically acceptable carrier and the conjugate of claim 1 .
11. A method of vaccinating an animal, the method comprising administering an effective amount of the conjugate of claim 1 to the animal.
12. A conjugate comprising:
an immune response modifier;
a linker represented by formula:
wherein A is CH or N, p is in a range from 1 to 50, R″ is a bond or -alkylene-O—, and R′ is a bond or alkylene that is optionally interrupted or terminated with one or more amide or ether groups; and
an antigen,
wherein the immune response modifier is covalently attached to the linker at * through a hydrazone functional group, and wherein the antigen is covalently attached to the linker at ** through an amide, disulfide, urea, thiourea, carbamate, or a carbon-sulfur or carbon-nitrogen bond alpha to an amide or sulfone or directly attached to a succinimide ring, and
wherein the immune response modifier comprises a 2-aminopyridine ring fused to a five-membered nitrogen-containing heterocyclic ring or a 4-aminopyrimidine ring fused to a five-membered nitrogen-containing heterocyclic ring.
13. The conjugate of claim 12 , wherein the immune response modifier is an imidazoquinoline amine, imidazonaphthyridine amine, pyrazoloquinoline amine, pyrazolonaphthyridine amine, or thiazoloquinoline amine, and wherein the hydrazone functional group is located at the 1-position or the 7-position of the imidazoquinoline amine, imidazonaphthyridine amine, pyrazoloquinoline amine, pyrazolonaphthyridine amine, or thiazoloquinoline amine.
14. The conjugate of claim 12 , wherein the antigen is a protein.
15. The conjugate of claim 12 , wherein the antigen is a vaccine.
16. The conjugate of claim 12 , wherein p is in a range from 2 to 16.
17. A pharmaceutical composition comprising a pharmaceutically acceptable carrier the conjugate of claim 12 .
18. A method of making the conjugate of claim 12 , the method comprising:
combining an antigen with a linker to provide a modified antigen, wherein the linker is represented by formula:
wherein A is CH or N, p is in a range from 1 to 50, R″ is a bond or -alkylene-O—, R′ is a bond or alkylene that is optionally interrupted or terminated with one or more amide or ether groups, and E is an amine- or thiol-reactive group; and
combining the modified antigen with a hydrazine- or hydrazide-substituted immune response modifier to provide the conjugate,
wherein the immune response modifier comprises a 2-aminopyridine ring fused to a five-membered nitrogen-containing heterocyclic ring or a 4-aminopyrimidine ring fused to a five-membered nitrogen-containing heterocyclic ring.
19. A method of vaccinating an animal, the method comprising administering an effective amount of the conjugate of claim 12 to the animal.
20. A method of inducing cytokine biosynthesis in an animal, the method comprising administering an effective amount of the conjugate of claim 12 to the animal.