RNA bacteriophage-based delivery system

• US 6,159,728 A
• Filed: 01/24/1995
• Issued: 12/12/2000
• Est. Priority Date: 06/26/1992
• Status: Expired due to Fees

• Current Assignee: BTG International Limited (Boston Scientific Corporation)
• Original Assignee: BTG International Limited (Boston Scientific Corporation)
• Inventors: Mastico, Robert Allan, Stockley, Peter George
• Primary Examiner(s): PRIEBE, SCOTT DAVID
• Application Number:
  US08/360,694
• Time in Patent Office: 2,149 Days
• Field of Search: 424/89, 424/93.2, 424/93.6, 514/44, 435/320.1, 435/455, 435/456, 435/471, 435/472, 435/375
• US Class Current: 435/320.1
• CPC Class Codes: A61K 9/5184 Virus capsids or envelopes enclosing drugs with additional exogenous lipids A61K9/127; bacterial membranes A61K9/5068
• CPC Class Codes: C07K 14/005 from viruses
• CPC Class Codes: C12N 15/1132 against retroviridae, e.g. HIV
• CPC Class Codes: C12N 15/87 Introduction of foreign genetic material using processes not otherwise provided for, e.g. co-transformation
• CPC Class Codes: C12N 2310/3513 Protein; Peptide
• CPC Class Codes: C12N 2310/3517 Marker; Tag
• CPC Class Codes: C12N 2795/18122 New viral proteins or individual genes, new structural or functional aspects of known viral proteins or genes
• CPC Class Codes: C12N 2795/18142 virus or viral particle as vehicle, e.g. encapsulating small organic molecule
• CPC Class Codes: Y10S 977/804 Containing nucleic acid
• CPC Class Codes: Y10S 977/808 Exterior attachment for targeting, e.g. drug targeting
• CPC Class Codes: Y10S 977/916 Gene therapy
• CPC Class Codes: Y10S 977/92 Detection of biochemical

Abstract

A delivery system, especially for delivery to targeted sites in the human or animal body, comprises capsids of the coat protein amino acid sequence of phage MS-2 or related phage, or a modification thereof which retains capsid-forming capability, and at least some of the capsids enclosing a moiety foreign to the genome of MS-2 or related phage.

Claims

1. A delivery system comprising a capsid formed from a coat protein of a bacteriophage selected from the group consisting of MS-2, R17, fr, GA, Qβ

, and SP and a foreign moiety enclosed in the capsid, wherein the foreign moiety is of a size sufficiently small to be enclosed in the capsid and wherein the foreign moiety is linked to a RNA sequence comprising a translational operator of the bacteriophage, which translational operator binds to the coat protein during formation of the capsid.

2. The delivery system of claim 1, wherein the bacteriophage is MS-2 or R17 and the RNA sequence comprises the sequence of SEQ ID NO:

1.

3. The delivery system of claim 2, wherein the base position at 11 of the sequence of SEQ ID NO:

1 is replaced with cytidine.

4. The delivery system of claim 1, wherein the foreign moiety is linked directly to the RNA sequence.

5. The delivery system of claim 1, wherein the foreign moiety is linked to the RNA sequence through a spacer moiety.

6. The delivery system of claim 1, wherein the N-terminal protuberant β

-hairpin of the coat protein of the capsid has been modified to provide a site suitable for attachment thereto of a targeting moiety.

7. The delivery system of claim 6, wherein the site is a cysteine residue.

8. The delivery system of claim 6, wherein a targeting moiety is directly attached to the coat protein or linked to the coat protein through a spacer moiety.

9. The delivery system of claim 8, wherein the targeting moiety comprises galactose.

10. The delivery system of claim 1, wherein the foreign moiety is selected from the group consisting of a gene, gene fragment, ribozyme, anti-sense oligonucleotide, cytotoxic agent and chemotherapeutic agent.

11. The delivery system of claim 1, wherein the bacteriophage is GA.

12. The delivery system of claim 1, wherein the bacteriophage is Qβ

.

13. The delivery system of claim 1, wherein the bacteriophage is SP.

14. The delivery system of claim 1, wherein the bacteriophage is fr.

15. A method of preparing a delivery system of claim 1, comprising:

providing the foreign moiety;

linking the foreign moiety to the RNA sequence to produce the foreign moiety linked to the RNA sequence;

providing the capsid; and

incorporating into the capsid the foreign moiety linked to the RNA sequence, such that the capsid encloses the foreign moiety.

16. The method of claim 15, wherein the foreign moiety linked to the RNA sequence is incorporated into the capsid by disassembly of the capsid at acid pH in the presence of the foreign moiety linked to the RNA sequence followed by reassembly of the capsid at an increased pH.