COMPOSITIONS AND RELATED METHODS FOR BLOCKING OFF-TARGET LOCALIZATION OF MANNOSYLATED DEXTRANS AND OTHER CD206 LIGANDS

1 . A method for increase target specificity of a mannosylated dextran therapeutic or diagnostic compound comprising:

a. administering at least a blocking compound comprising a backbone and one or more CD206 targeting moieties attached thereto;

b. administering an effective amount of the mannosylated dextran therapeutic or diagnostic compound comprising a dextran backbone and one or more CD206 targeting moieties and one or more therapeutic or diagnostic agents attached thereto; and

wherein the molecular mass of the blocking composition backbone is at least two times larger than the molecular mass of the mannosylated dextran backbone compound.

2 . The method of claim 1 , wherein the mannosylated dextran therapeutic or diagnostic compound is a compound of Formula (I):

wherein

each X is independently H, L1-A, or L2-R;

each L1 and L2 are independently linkers;

each A independently comprises a therapeutic agent, a diagnostic agent, or H;

each R independently comprises a mannose-binding C-type lectin receptor targeting moiety or H;

and n is an integer greater than zero; and

wherein at least one R comprises a mannose-binding C-type lectin receptor targeting moiety selected from the group consisting of mannose, fucose, and n-acetylglucosamine and at least one A comprises a therapeutic agent or diagnostic agent.

3 . The method of claim 1 wherein the blocking compound backbone is selected from a list consisting of: dextran, cellulose, polyethylene glycol, and polypeptides.

4 . The method of claim 3 , wherein the backbone is a dextran.

5 . The method of claim 1 , wherein the one or more CD206 targeting moieties is attached to the blocking compound backbone with a leash.

6 . The method of claim 1 , wherein the blocking compound backbone is at least about 35 kDa.

7 . The method of claim 6 , wherein the blocking compound backbone is between about 35 kDa and about 180 kDa.

8 . The method of claim 6 , wherein the blocking compound backbone is between about 35 kDa and about 500 kDa.

9 . The method of claim 6 wherein the blocking compound is a compound of Formula (I):

wherein

each X is H;

each R independently comprises a mannose-binding C-type lectin receptor targeting moiety or H;

and n is an integer greater than zero; and

wherein at least one R comprises a mannose-binding C-type lectin receptor targeting moiety selected from the group consisting of mannose, fucose, and n-acetylglucosamine.

10 . The method of claim 6 , wherein the blocking compound backbone is about 110 kDa and the mannosylated dextran therapeutic or diagnostic compound dextran backbone is about 10 kDa.

11 . The method of claim 6 , wherein the blocking compound does not contain a therapeutic or diagnostic agent.

12 . The method of claim 1 , wherein the step of administering the blocking compound is followed by a time interval of at least zero to 60 minutes before the step of administering the mannosylated dextran therapeutic or diagnostic compound.

13 . The method of claim 12 , wherein the time interval is from about ten minutes to about twenty minutes.

14 . The method of claim 1 , wherein the blocking compound and the mannosylated dextran therapeutic or diagnostic compound are administered simultaneously.

15 . The method of claim 1 , wherein the mannosylated dextran therapeutic or diagnostic compound comprises at least one therapeutic moiety.

16 . The method of claim 15 , wherein the portion of the injected dose of the mannosylated dextran therapeutic or diagnostic compound that localizes to a desired target tissue other than the liver, kidney, and/or spleen is higher than the localizing portion of the mannosylated dextran therapeutic or diagnostic compound without administration of the blocking compound.

17 . The method of claim 15 , wherein the effective dose of the mannosylated dextran therapeutic or diagnostic compound is lower than the effective does of the mannosylated dextran therapeutic or diagnostic compound without administration of the blocking compound.

18 . The method of claim 1 , wherein the blocking compound preferentially binds to CD206 expressing cells in the liver, kidney, and/or spleen.

19 . The method of claim 18 , wherein the mannosylated dextran therapeutic or diagnostic compound has decreased binding to CD206 cells in the liver, kidney, and/or spleen relative to a subject administered a comparable dose of mannosylated dextran therapeutic or diagnostic compound without administration of the blocking compound.

20 . The method of claim 1 , wherein the subject has been diagnosed with an autoimmune disease, an inflammatory disease, or cancer.

21 . A method for increase target specificity of a mannosylated dextran therapeutic or diagnostic compound comprising:

a. administering at least a blocking compound comprising a backbone and one or more CD206 targeting moieties attached thereto wherein the blocking compound is from about 35 kDa to about 500 kDa;

b. administering an effective amount of the mannosylated dextran therapeutic or diagnostic compound comprising a dextran backbone and one or more CD206 targeting moieties and one or more therapeutic or diagnostic agents attached thereto; and

wherein the molecular mass of the blocking composition backbone is at least two times larger than the molecular mass of the mannosylated dextran backbone compound.

22 . A kit for the diagnosis or treatment of a subject in need thereof comprising:

a. a blocking compound comprising a backbone and one or more CD206 targeting moieties attached thereto;

b. mannosylated dextran therapeutic or diagnostic compound comprising a dextran backbone and one or more CD206 targeting moieties and one or more therapeutic agents attached thereto; and

wherein the molecular mass of the blocking composition backbone is at least two times larger than the molecular mass of the mannosylated dextran backbone compound.

23 . The kit of claim 22 , wherein the mannosylated dextran therapeutic or diagnostic compound is a compound of Formula (I):

wherein

each X is independently H, L1-A, or L2-R;

each L1 and L2 are independently linkers;

each A independently comprises a therapeutic agent, a diagnostic agent, or H;

each R independently comprises a mannose-binding C-type lectin receptor targeting moiety or H;

and n is an integer greater than zero; and

wherein at least one R comprises a mannose-binding C-type lectin receptor targeting moiety selected from the group consisting of mannose, fucose, and n-acetylglucosamine and at least one A comprises a therapeutic agent or diagnostic agent.

24 . The kit of claim 22 , wherein the blocking compound backbone is about 110 kDa and the mannosylated dextran therapeutic or diagnostic compound dextran backbone is about 10 kDa.