Inhibition of Xenoreactive Antibodies

Abstract

One aspect of the present invention relates to methods and compositions for attenuating xenograft rejection by administering, to an animal receiving the xenograft, an amount of a polymer-derivatized xenoantigen (hereinafter “xenopolymer”) effective for inhibiting or lessening the severity of hyperacute rejection response (HAR), or other immunological response to the graft, that is dependent on the presence of the xenoantigen on the grafted tissues or cells. In certain embodiments, the xenopolymer is administered in an amount sufficient to neutralize host antibodies (“xenoreactive antibodies” or “XNA”) immunoreactive with the xenoantigen. The xenopolymer may additionally, or alternatively, be used as a tolerogen (or anergen) for the xenoantigen, e.g., able to suppress, to some degree, the production/secretion of XNAs by the immune system of the host.

1 .- 95 . (canceled) 
     
     
         96 . A polymer comprising:
 a polymer scaffold unit; and   one or more oligosaccharide moieties covalently linked to the polymer scaffold unit,   wherein the polymer scaffold unit used for the linking of the one or more oligosaccharide moieties comprises octa(amino)polyethylene glycol.   
     
     
         97 . The polymer of  claim 96 , wherein the polymer is homogenous with respect to the one or more oligosaccharide moieties thereon. 
     
     
         98 . The polymer of  claim 96 , wherein each of the oligosaccharide moieties includes one or more of αGal(1,3)βGal; αGal(1,3)βGal(1,4)βGlcNAc; or αGal(1,3)βGal (1,4)βGlc moieties. 
     
     
         99 . The polymer of  claim 96 , wherein each of the oligosaccharide moieties is bound to the polymer scaffold unit by an amide linkage. 
     
     
         100 . The polymer of  claim 96 , wherein each of the oligosaccharide moieties includes an epitope that is cross-reactive with a xenoreactive antibody against α-galactosyl moieties. 
     
     
         101 . The polymer of  claim 96 , wherein the polymer scaffold units, prior to the linking of the one or more oligosaccharide moieties, have a molecular weight in the range of 1,000 Da to 100,000 Da. 
     
     
         102 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties includes an epitope which is cross-reactive with a xenoreactive antibody against α-galactosyl moieties. 
     
     
         103 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties includes an αGal(1,3)Gal moiety represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein:
 R, independently for each occurrence, represents H or a C 1 -C 6  alkyl or other hydroxyl protecting group; 
 R′ is absent or represents an oligosaccharide consisting of 1-8 saccharide residues; and 
 X represents a bond or linker moiety linking the oligosaccharide moiety to the polymer backbone. 
 
     
     
         104 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties includes an oligosaccharide represented by one of the general formula: 
       
         
           
           
               
               
           
         
         wherein, 
         R1, independently for each occurrence, is H, —OR, —SR or N(H)-Y-R; 
         R, independently for each occurrence, represents H or a C1-C6 alkyl or other hydroxyl protecting group; 
         R2 is a C1-C6 alkyl; 
         Y, independently for each occurrence, is absent, or —C(S)—, —S(0)2—, —C(O)-A-; 
         X represents a bond or linker moiety linking the oligosaccharide moiety to the polymer backbone; 
         Z is 0 or S; and 
         A is —NH—, —NH—(C 1-C6 alkyl)-; —NH—(C1-C6 alkenyl)-, -0-, —O—(C1-C6 alkyl)-, -0-(C1-C6 alkenyl)-, —S—, —S—(C1-C6 alkyl)-, —S—(C1-C6 alkenyl)-. 
       
     
     
         105 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties includes one or more of αGal(1,3)βGal; αGal(1,3)βGal(1,4)βGlcNAc; or αGal(1,3)βGal(1,4)βGlc moieties. 
     
     
         106 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties is a di-, tri-, tetra- or penta-oligosaccharide. 
     
     
         107 . The polymer of  claim 96 , wherein each of the one or more oligosaccharide moieties includes one or more of: αGal(1,2)Gal, αGal(1,4)Gal, βGal(1,3)GalNAc or 3-O-sulphated galactose (SO 4 -3Gal). 
     
     
         108 . The polymer of  claim 96 , wherein the polymer induces B cell anergy for xenoantigens. 
     
     
         109 . The polymer of  claim 96 , wherein the polymer has a polydispersity of 20 or less. 
     
     
         110 . The polymer of  claim 96  wherein the polymer is non-immunogenic. 
     
     
         111 . The polymer of  claim 96 , wherein the polymer is tolerogenic for xenoantigens. 
     
     
         112 . A polymer comprising a plurality of polymer scaffold units and one or more oligosaccharide moieties covalently linked to the polymer scaffold units, wherein separate scaffold units are cross-linked to one another. 
     
     
         113 . The polymer of  claim 112 , wherein the polymer is homogenous with respect to one or more oligosaccharide moieties thereon. 
     
     
         114 . The polymer of  claim 112 , wherein each of the oligosaccharide moieties includes one or more of αGal(1,3)βGal; αGal(1,3)βGal(1,4)βGlcNAc; or αGal(1,3)βGal(1,4)βGlc moieties. 
     
     
         115 . The polymer of  claim 112 , wherein the polymer scaffold units, prior to the linking of the one or more oligosaccharide moieties, comprise a plurality of nucleophilic or electrophilic functional groups and the one or more oligosaccharide moieties comprise a functional group capable of reacting with the functional groups on the polymer scaffold units. 
     
     
         116 . The polymer of  claim 112 , wherein the polymer scaffold units, prior to the linking of the one or more oligosaccharide moieties, comprises octa(amino)polyethylene glycol. 
     
     
         117 . The polymer of  claim 115 , wherein each functional group on the polymer scaffold unit and each functional group on the one or more oligosaccharide moieties are a pair of complementary functional groups that are selected from the group consisting of:
 (a) amine and carboxylic acid;   (b) alcohol and alkyl halide or sulfonate;   (c) thiol and alkyl halide or alkyl sulfonate;   (d) phosphine and alkyl halide or alkyl sulfonate;   (e) phosphite and alkyl halide or alkyl sulfonate; and   (f) aldehyde or ketone and amine.   
     
     
         118 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties is bound to the polymer scaffold units by an ether, thioether, or phosphate linkage. 
     
     
         119 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties is bound to the polymer scaffold unit by an amide linkage. 
     
     
         120 . The polymer of  claim 112 , wherein each of the oligosaccharide moieties includes an epitope that is cross-reactive with a xenoreactive antibody against α-galactosyl moieties. 
     
     
         121 . The polymer of  claim 115 , wherein the nucleophilic or electrophilic functional groups on the polymer scaffold units are selected from the group consisting of amines, alcohols, thiols, selenols, phosphines, aldehydes, ketones, acid chlorides, acids, esters, alkyl halides, and alkyl sulfonates. 
     
     
         122 . The polymer of  claim 115 , wherein the functional groups on the polymer scaffold units are amino or carboxylate moieties, and the functional groups on the oligosaccharide moieties react therewith to form amide linkages. 
     
     
         123 . The polymer of  claim 112 , wherein the polymer scaffold units, prior to the linking of the one or more oligosaccharide moieties, have a molecular weight in the range of 1,000 Da to 100,000 Da. 
     
     
         124 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties includes an epitope which is cross-reactive with an xenoreactive antibody against α-galactosyl moieties. 
     
     
         125 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties includes an αGal(1,3)Gal moiety represented by the general formula: 
       
         
           
           
               
               
           
         
       
       wherein:
 R, independently for each occurrence, represents H or a C 1 -C 6  alkyl or other hydroxyl protecting group; 
 R′ is absent or represents an oligosaccharide consisting of 1-8 saccharide residues; and 
 X represents a bond or linker moiety linking the oligosaccharide moiety to the polymer backbone. 
 
     
     
         126 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties includes an oligosaccharide represented by one of the general formula: 
       
         
           
           
               
               
           
         
         wherein, 
         R1, independently for each occurrence, is H, —OR, —SR or N(H)-Y-R; 
         R, independently for each occurrence, represents H or a C1-C6 alkyl or other hydroxyl protecting group; 
         R2 is a C1-C6 alkyl; 
         Y, independently for each occurrence, is absent, or —C(S)—, —S(0)2-, —C(O)-A-; 
         X represents a bond or linker moiety linking the oligosaccharide moiety to the polymer backbone; 
         Z is 0 or S; and 
         A is —NH—, —NH—(C 1-C6 alkyl)-; —NH—(C1-C6 alkenyl)-, -0-, —O—(C1-C6 alkyl)-, -0-(C1-C6 alkenyl)-, —S—, —S—(C1-C6 alkyl)-, —S—(C1-C6 alkenyl)-. 
       
     
     
         127 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties includes one or more of αGal(1,3)βGal; αGal(1,3)βGal(1,4)βGlcNAc; or αGal(1,3)βGal(1,4)βGlc moieties. 
     
     
         128 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties is a di-, tri-, tetra- or penta-oligosaccharide. 
     
     
         129 . The polymer of  claim 112 , wherein each of the one or more oligosaccharide moieties includes one or more of: αGal(1,2)Gal, αGal(1,4)Gal, βGal(1,3)GalNAc or 3-O-sulphated galactose (S0 4 -3Gal). 
     
     
         130 . The polymer of  claim 112 , wherein the polymer induces B cell anergy for xenoantigens. 
     
     
         131 . The polymer of  claim 112 , wherein the polymer has a polydispersity of 20 or less. 
     
     
         132 . The polymer of  claim 112 , wherein the polymer is non-immunogenic. 
     
     
         133 . The polymer of  claim 112 , wherein the polymer is tolerogenic for xenoantigens. 
     
     
         134 . A composition comprising the polymer of  claim 96 . 
     
     
         135 . The composition of  claim 134 , further comprising one or more B cells. 
     
     
         136 . The composition of  claim 134 , further comprising one or more antibodies. 
     
     
         137 . A composition comprising the polymer of  claim 112 . 
     
     
         138 . The composition of  claim 137 , further comprising one or more B cells. 
     
     
         139 . The composition of  claim 137 , further comprrising one or more antibodies.