METHODS AND COMPOSITIONS FOR INCREASING ENZYME ACTIVITY IN THE CNS
Provided herein are methods and compositions for treating a subject suffering from an enzyme deficiency in the central nervous system (CNS). The bifunctional fusion antibodies provided herein comprise an antibody to an endogenous blood brain barrier (BBB) receptor and an enzyme deficient in mucopolysaccharidosis III (MPS-III). The fusion antibodies provided herein comprise N-sulfoglucosamine sulfohydrolase (SGSH), alpha-N-acetylgulcosaminidase (NAGLU), heparin-alpha-glucosaminide N-acetyltransferase (HGSNAT), or N-acetylglucosamine-6-sulfatase (GNS). The methods of treating an enzyme deficiency in the CNS comprise systemic administration of a fusion antibody provided herein.
1 .- 61 . (canceled)
62 . A fusion antibody comprising: (a) a fusion protein comprising the amino acid sequences of an immunoglobulin heavy chain and a SGSH, and (b) an immunoglobulin light chain; wherein the fusion antibody crosses the blood brain barrier (BBB).
63 . The fusion antibody of claim 62 , wherein the amino acid sequence of the SGSH is covalently linked to the carboxy terminus of the amino acid sequence of the immunoglobulin heavy chain.
64 . The fusion antibody of claim 62 , wherein the fusion antibody catalyzes hydrolysis of sulfate groups from heparan sulfate.
65 . The fusion antibody of claim 62 , wherein the fusion antibody is post-translationally modified by a sulfatase modifying factor type 1 (SUMF1).
66 . The fusion antibody of claim 65 , wherein the post-translational modification comprises a cysteine to formylglycine conversion.
67 . The fusion antibody of claim 62 , wherein fusion antibody comprises a formylglycine.
68 . The fusion antibody of claim 62 , wherein the fusion protein further comprises a linker between the amino acid sequence of the SGSH and the carboxy terminus of the amino acid sequence of the immunoglobulin heavy chain.
69 . The fusion antibody of claim 62 , wherein the SGSH specific activity of the fusion antibody is at least about 1000 units/mg.
70 . The fusion antibody of claim 62 , wherein the SGSH retains at least 20% of its activity compared to its activity as a separate entity.
71 . The fusion antibody of claim 62 , wherein the SGSH and the immunoglobulin each retains at least 20% of its activity compared to its activity as a separate entity.
72 . The fusion antibody of claim 62 , wherein the immunoglobulin heavy chain is an immunoglobulin heavy chain of IgG.
73 . The fusion antibody of claim 62 , wherein the immunoglobulin heavy chain is an immunoglobulin heavy chain of IgG1 class.
74 . The fusion antibody of claim 62 , wherein the immunoglobulin heavy chain comprises a CDR1 corresponding to the amino acid sequence of SEQ ID NO:1, a CDR2 corresponding to the amino acid sequence of SEQ ID NO:2, or a CDR3 corresponding to the amino acid sequence of SEQ ID NO:3.
75 . The fusion antibody of claim 62 , wherein the immunoglobulin light chain is an immunoglobulin light chain of kappa or lambda class.
76 . The fusion antibody of claim 62 , wherein the immunoglobulin light chain comprises a CDR1 corresponding to the amino acid sequence of SEQ ID NO:4, a CDR2 corresponding to the amino acid sequence of SEQ ID NO:5, or a CDR3 corresponding to the amino acid sequence of SEQ ID NO:6.
77 . The fusion antibody of claim 62 , wherein the fusion antibody crosses the BBB by binding an endogenous BBB receptor-mediated transport system.
78 . The fusion antibody of claim 62 , wherein the fusion antibody crosses the BBB via an endogenous BBB receptor selected from the group consisting of the insulin receptor, transferrin receptor, leptin receptor, lipoprotein receptor, and the IGF receptor.
79 . The fusion antibody of claim 62 , wherein the fusion antibody crosses the BBB by binding an insulin receptor.
80 . A pharmaceutical composition comprising a therapeutically effective amount of a fusion antibody of claim 62 , and a pharmaceutically acceptable excipient.
81 . An isolated polynucleotide encoding the fusion antibody of claim 62 .
82 . The isolated polynucleotide of claim 81 , wherein the isolated polynucleotide comprises the nucleic acid sequence of SEQ ID NO:14.
83 . A vector comprising the isolated polynucleotide of claim 81 .
84 . The vector of claim 83 comprising the nucleic acid sequence of SEQ ID NO:14.
85 . A host cell comprising the vector of claim 83 .
86 . The host cell of claim 85 , wherein the host cell is a Chinese Hamster Ovary (CHO) cell.
87 .- 171 . (canceled)