Microencapsulated DNA for vaccination and gene therapy

Abstract

A microparticle contains DNA coding for a polypeptide and oral administration of the microparticle leads to its expression. DNA coding for an immunogen is for stimulating antibody formation in a recipient and DNA coding for a non-immunogenic polypeptide is for gene therapy applications. DNA is incorporated into the microparticle without destruction of its function.

1 . A composition comprising a microparticle and DNA, wherein the DNA is inside the microparticle and comprises a sequence coding for a polypeptide, and wherein the microparticle is adapted to induce expression of the coding sequence following administration to a recipient.  
     
     
         2 . A composition according to  claim 1  adapted to induce expression of the coding sequence following oral administration.  
     
     
         3 . A composition according to  claim 1  comprising double-stranded DNA selected from (i) plasmid DNA and (ii) DNA derived from plasmid DNA by one or more of insertion, deletion and substitution.  
     
     
         4 . A composition according to  claim 1  wherein the DNA comprises a sequence promoting transcription of the coding sequence.  
     
     
         5 . A composition according to  claim 1  is non-toxic and pharmaceutically acceptable and wherein the microparticle consists of or comprises a bio-degradable polymer.  
     
     
         6 . A composition according to  claim 5  wherein the polymer is selected from the group consisting of a lactide containing polymer, a glycolide-containing polymer, and a polymer comprising lactide and glycolide.  
     
     
         7 . A composition according to  claim 5  wherein the polymer comprises poly (DL-lactide-co-glycolide).  
     
     
         8 . A composition comprising a plurality of microparticles according to  claim 1  wherein at least 50% of the microparticles are in the size range 0.01 μm to 30 μm.  
     
     
         9 . A composition according to  claim 8  wherein at least 50% of the microparticles are in the size range 1 μm to 10 μm.  
     
     
         10 . A composition according to  claim 1 , comprising a DNA sequence coding for an immunogen and adapted to induce expression of that immunogen in a recipient, and adapted to induce production of antibodies specific to that immunogen in the recipient.  
     
     
         11 . A composition according to  claim 10  adapted to induce production of IgA antibodies.  
     
     
         12 . A composition according to  claim 1  adapted for vaccinating a mammal, wherein vaccination is obtained by production of antibodies by the mammal in response to the immunogen, itself produced by expression of the DNA coding sequence.  
     
     
         13 . A vaccine for eliciting antibodies against an immunogen, comprising a composition according to  claim 8  and a pharmaceutically acceptable carrier, wherein the DNA sequence codes for said immunogen.  
     
     
         14 . A vaccine according to  claim 13  wherein said immunogen is an immunogenic component of an organism selected from the group consisting of a virus, a bacterium and other pathogenic microorganisms.  
     
     
         15 . A vaccine according to  claim 14  wherein the DNA sequence codes for a viral protein.  
     
     
         16 . A vaccine according to  claim 13 , comprising first and second vaccine components, the first vaccine component comprising DNA inside a microparticle wherein the DNA includes a sequence coding for an immunogen and wherein the microparticle has a first half-life in vivo, and a second vaccine component comprising DNA inside a microparticle, wherein the DNA contains a sequence coding for an immunogen and wherein the microparticle has a second half-life in vivo.  
     
     
         17 . A vaccine according to  claim 16  wherein the immunogen of the first vaccine component and the immunogen of the second vaccine component are the same.  
     
     
         18 . A vaccine according to  claim 16  wherein the ratio of the first and second half-lives is at least 2:1.  
     
     
         19 . A composition according to  claim 1  adapted to induce, in a recipient, expression of a desired, non-immunogenic gene product.  
     
     
         20 . A composition according to  claim 19  for inducing expression of a desired non-immunogenic product, which product is (i) previously substantially not expressed, or (ii) previously expressed at a level which it is desired to increase.  
     
     
         21 . A composition according to  claim 19  for treatment or prevention of a disease caused by non-expression or reduced expression or absence of a gene product, wherein the DNA coding sequence of the composition codes for said gene product.  
     
     
         22 . A pharmaceutical composition comprising polymer-encapsulated DNA and having a water content of less than 5% by weight.  
     
     
         23 . A pharmaceutical composition comprising polymer-encapsulated DNA and having a water content of less than 5%, obtained by freeze-drying a composition according to  claim 1 .  
     
     
         24 . A method of preparing a pharmaceutical composition for storage, comprising preparing an aqueous solution of polymer capsules, said capsules containing DNA, and drying the solution to a water content of less than 5%.  
     
     
         25 . A method of making microparticles comprising the steps of:—
 i. preparing a mixture of DNA and microparticle precursor;    ii. forming microparticles that contains DNA; and    iii. separating DNA-containing microparticles from the mixture, wherein DNA in the DNA-containing microparticles comprises a sequence coding for a polypeptide and wherein the microparticles are adapted to induce expression of the coding sequence in a recipient.    
     
     
         26 . A method according to  claim 25  comprising:—
 a. forming a plurality of microparticles under conditions such that the ability of the DNA to induce expression of its coding sequence is at least 10% of its ability to induce expression of its coding sequence prior to microparticle formation.    
     
     
         27 . A method according to  claim 25  comprising forming the microparticles under conditions of reduced shear stress such that at least 10% of encapsulated DNA retains its ability to induce expression of its coding sequence.  
     
     
         28 . A method according to  claim 25  comprising forming microparticles in the size range 0.01 μm to 30 μm.  
     
     
         29 . A method according to  claim 28  wherein the DNA is circular, plasmid DNA.  
     
     
         30 . A method according to  claim 25  further comprising freeze drying the microparticle.  
     
     
         31 . A method of encapsulating DNA in a microparticle, wherein the DNA comprises a sequence coding for a polypeptide and is adapted to induce expression of the coding sequence, comprising the steps of preparing a mixture of the DNA and a water-in-oil-in-water emulsion suitable to form microparticles, forming microparticles that contain DNA and separating DNA-containing microparticles from the mixture by centrifugation, characterised in that DNA retains its ability to induce expression of its coding sequence.  
     
     
         32 . A method of vaccination, comprising administering a vaccine according to  claim 13 .  
     
     
         33 . A method of vaccination according to  claim 32  wherein vaccination is obtained by eliciting antibodies to the immunogen expressed from the coding sequence.  
     
     
         34 . A method of inducing production, in a recipient, of an antibody, comprising administering to said recipient an effective amount of a composition according to  claim 10 .  
     
     
         35 . A method of gene therapy comprising identifying a gene product that is to be expressed, preparing a composition according to  claim 19  wherein the coding sequence codes for the gene product and administering the composition.  
     
     
         36 . A method according to  claim 35  wherein administration is oral or intra-nasal.  
     
     
         37 . A method of inducing mucosal immunity comprising the administration of a composition according to  claim 1 .  
     
     
         38 . A method of inducing the production of IgA antibodies comprising the administration of a composition according to  claim 1.