Methods and compositions for increasing n-acetylglucosaminidase activity in the cns

Abstract

Provided herein are methods and compositions for treating a subject suffering from an enzyme deficiency in the central nervous system (CNS). The bifunctional fusion antibody provided herein comprise an antibody to an endogenous blood brain barrier (BBB) receptor and an enzyme deficient in mucopolysaccharidosis IIIB (MPS-IIIB). The fusion antibodies provided herein comprise alpha-N-acetylgulcosaminidase (NAGLU). The methods of treating an enzyme deficiency in the CNS comprise systemic administration of a fusion antibody provided herein.

1 .- 86 . (canceled) 
     
     
         87 . A fusion antibody comprising: a fusion protein comprising the amino acid sequences of an immunoglobulin and a NAGLU, wherein the fusion antibody crosses the blood brain barrier (BBB) via a transferrin receptor and wherein the NAGLU retains at least 20% of its activity compared to its activity as a separate entity. 
     
     
         88 . The fusion antibody of  claim 87 , wherein the immunoglobulin comprises an immunoglobulin heavy chain and an immunoglobulin light chain. 
     
     
         89 . The fusion antibody of  claim 87 , wherein the fusion antibody has a molecular weight of at least 350 kDa. 
     
     
         90 . The fusion antibody of  claim 87 , wherein the amino acid sequence of the NAGLU is covalently linked to the carboxy terminus of the amino acid sequence of the immunoglobulin. 
     
     
         91 . The fusion antibody of  claim 87 , wherein the fusion antibody catalyzes hydrolysis of terminal N-acetyl-D-glucosamine residues in N-acetyl-alpha-D-glucosaminides from heparan sulfate. 
     
     
         92 . The fusion antibody of  claim 87 , wherein the fusion protein further comprises a linker between the amino acid sequence of the NAGLU and the amino acid sequence of the immunoglobulin. 
     
     
         93 . The fusion antibody of  claim 87 , wherein the linker is 80%, 85%, 90%, 95%, 96%, 97%, 98%, 99% or 100% identical to amino acids 462-484 of SEQ ID NO:10. 
     
     
         94 . The fusion antibody of  claim 87 , wherein the NAGLU specific activity of the fusion antibody is at least about 10000 units/mg. 
     
     
         95 . The fusion antibody of  claim 87 , wherein the immunoglobulin retains at least 20% of its activity compared to its activity as a separate entity. 
     
     
         96 . The fusion antibody of  claim 87 , wherein the NAGLU and the immunoglobulin each retains at least 20% of its activity compared to its activity as a separate entity. 
     
     
         97 . The fusion antibody of  claim 88 , wherein the immunoglobulin heavy chain is an immunoglobulin heavy chain of IgG. 
     
     
         98 . The fusion antibody of  claim 88 , wherein the immunoglobulin heavy chain is an immunoglobulin heavy chain of IgG1 class. 
     
     
         99 . The fusion antibody of  claim 88 , wherein the immunoglobulin light chain is an immunoglobulin light chain of kappa or lambda class. 
     
     
         100 . A pharmaceutical composition comprising a therapeutically effective amount of a fusion antibody of  claim 87 , and a pharmaceutically acceptable excipient. 
     
     
         101 . An isolated polynucleotide encoding the fusion antibody of  claim 87 . 
     
     
         102 . A vector comprising the isolated polynucleotide of  claim 101 . 
     
     
         103 . A host cell comprising the vector of  claim 102 . 
     
     
         104 . The host cell of  claim 103 , wherein the host cell is a Chinese Hamster Ovary (CHO) cell. 
     
     
         105 . A method for treating an alpha-N-acetylgulcosaminidase (NAGLU) deficiency in the central nervous system of a subject in need thereof, comprising systemically administering to the subject a therapeutically effective dose of a fusion antibody having NAGLU activity, wherein the fusion antibody comprises: a fusion protein comprising the amino acid sequences of an immunoglobulin and a NAGLU, wherein the fusion antibody crosses the blood brain barrier (BBB) via a transferrin receptor. 
     
     
         106 . The method of  claim 105 , wherein the immunoglobulin comprises an immunoglobulin heavy chain and an immunoglobulin light chain. 
     
     
         107 . The method of  claim 105 , wherein the fusion antibody has a molecular weight of at least 350 kDa. 
     
     
         108 . The method of  claim 105 , wherein the amino acid sequence of the NAGLU is covalently linked to the carboxy terminus of the amino acid sequence of the immunoglobulin. 
     
     
         109 . The method of  claim 105 , wherein the fusion antibody catalyzes hydrolysis of terminal N-acetyl-D-glucosamine residues in N-acetyl-alpha-D-glucosaminides of heparan sulfate. 
     
     
         110 . The method of  claim 105 , wherein the NAGLU retains at least 20% of its activity compared to its activity as a separate entity. 
     
     
         111 . The method of  claim 105 , wherein the NAGLU and the immunoglobulin each retains at least 20% of its activity compared to its activity as a separate entity.