Methods of producing recombinant complement proteins, vectors and therapeutic uses thereof

An expression vector or system according to any preceding claim, wherein the expression vector comprises a nucleic acid molecule encoding a translation initiation sequence.

An expression vector or system according to any preceding claim, wherein the expression vector further comprises a nucleic acid molecule encoding an internal ribosome entry site (IRES), preferably wherein the nucleic acid molecule encoding an IRES is positioned between the nucleic acid molecule encoding the precursor Complement Factor I protein or variant thereof and the nucleic acid molecule encoding the furin protein or variant thereof.

An expression vector or system according to any preceding claim, wherein the recombinant mature human Complement Factor I protein comprises a first amino acid sequence selected from an amino acid sequence as set forth in SEQ. ID. No.2 (heavy chain) or an amino acid sequence having at least 85% sequence identity to the amino acid sequence as set forth in SEQ. ID. No. 2, and a second amino acid sequence as set forth in SEQ. ID. No. 3 (light chain) or an amino acid sequence having at least 85% sequence identity to the amino acid sequence set forth in SEQ. ID. No. 3, wherein the first and second amino acid sequences are linked via a disulphide bond.

An expression vector or system according to any preceding claim, wherein the recombinant precursor human Complement Factor I comprises an amino acid sequence as set forth in SEQ. ID. No. 1, or an amino acid sequence having at least 90% sequence identity to the amino acid sequence as set forth in SEQ. ID. No. 1, e.g. 91, 92, 93, 94, 95, 96, 97, 98 or 99% sequence identity.

An expression vector or system according to any preceding claim, wherein the furin protein comprises an amino acid sequence selected from an amino acid sequence as set forth in SEQ. ID. No. 5 or an amino acid sequence having at least 85% sequence identity to the amino acid sequence set forth in SEQ. ID. No 5.

An expression vector or system according to any preceding claim, wherein the vector comprises a nucleic acid sequence selected from the nucleic acid sequence as set forth in SEQ. ID. No. 10 or a nucleic acid sequence having at least 85% sequence identity to the nucleic acid sequence as set forth in SEQ. ID. No. 10.

An expression system for producing a recombinant mature Complement Factor I protein or variant thereof, the expression system comprising:

• a. a nucleic acid molecule encoding a recombinant precursor Complement Factor I protein or variant thereof;
• and
• b. a nucleic acid molecule encoding a furin protein or variant thereof wherein said furin protein or variant thereof is capable of cleaving the encoded precursor Complement Factor I protein to produce a recombinant mature Complement Factor I protein, wherein optionally the furin protein or variant thereof is capable of cleaving greater than 80%, 85%, 90% or 95% of the encoded precursor Complement Factor I protein.

An expression vector or system according to any preceding claim for use as a medicament.

An adeno-associated viral (AAV) vector particle comprising

• a. a nucleic acid sequence encoding a precursor Complement Factor I protein or variant thereof;
• and
• b. a nucleic acid sequence encoding a furin protein or variant thereof wherein said furin protein or variant thereof is capable of cleaving the encoded precursor Complement Factor I protein to produce a recombinant mature Complement Factor I protein.

A method for producing a recombinant mature Complement Factor I protein or variant thereof, the method comprising:

• a. expressing a recombinant precursor Complement Factor I protein or variant thereof and a recombinant furin protein or variant thereof in a host cell under conditions suitable for the expressed furin protein or variant thereof to cleave the expressed recombinant precursor Complement Factor I protein or variant thereof to form the recombinant mature Complement Factor I protein or variant thereof, wherein optionally greater than 80% of the recombinant precursor complement factor I protein or variant thereof is cleaved by the furin protein or variant thereof.