Classifications

• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/0005—Vertebrate antigens
  • A61K39/0011—Cancer antigens
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/02—Bacterial antigens
  • A61K39/07—Bacillus
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K39/39—Medicinal preparations containing antigens or antibodies characterised by the immunostimulating additives, e.g. chemical adjuvants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P31/00—Antiinfectives, i.e. antibiotics, antiseptics, chemotherapeutics
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P35/00—Antineoplastic agents
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P37/00—Drugs for immunological or allergic disorders
  • A61P37/02—Immunomodulators
  • A61P37/04—Immunostimulants
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61P—SPECIFIC THERAPEUTIC ACTIVITY OF CHEMICAL COMPOUNDS OR MEDICINAL PREPARATIONS
  • A61P43/00—Drugs for specific purposes, not provided for in groups A61P1/00-A61P41/00
• • A—HUMAN NECESSITIES
  • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
  • A61K—PREPARATIONS FOR MEDICAL, DENTAL OR TOILETRY PURPOSES
  • A61K39/00—Medicinal preparations containing antigens or antibodies
  • A61K2039/555—Medicinal preparations containing antigens or antibodies characterised by a specific combination antigen/adjuvant
  • A61K2039/55511—Organic adjuvants
  • A61K2039/55555—Liposomes; Vesicles, e.g. nanoparticles; Spheres, e.g. nanospheres; Polymers

Definitions

• the present invention relates to microparticle and pharmaceutical compositions comprising stable, immunogenic, microencapsulated single-stranded ribonucleic acid (RNA), which stimulates an immune response in mammalian cells.
• RNA ribonucleic acid
• the mammalian immune system possesses a specialised 'early warning system 1 in the form of a panel of detectors to rapidly sense and trigger responses to the presence of microbial invaders.
• the various 'toll-like receptors' (TLRs) recognise diverse structures and chemicals that are conserved in pathogens but are not found in multicellular organisms. Stimulation of a TLR with its appropriate agonist results in the activation of signalling pathways leading to the production of specific proinflammatory and / or antiviral cytokine(s).
• TLR agonists such as CpG oligodeoxynucleotides, as immunotherapeutics and vaccine adjuvants (see for example Nature Reviews Immunology 2004, Vol. 4 pages 248-257 and pages 512-520).
• type I interferons IFN- ⁇ and IFN- ⁇
• Type I interferons are involved very early on in the innate immune response and are critical to rapidly establishing an antiviral state following infection.
• Type I interferons also modulate any subsequent adaptive response to virus; encouraging dendritic cell cross priming and the induction of cytotoxic T- lymphocyte (CTL) responses.
• CTL cytotoxic T- lymphocyte
• Plasmacytoid dendritic cells can produce extremely high levels of type I interferon (up-to 1000 times more than conventional cells). It is thought that plasmacytoid dendritic cells are responsible for systemic interferon responses to many viral infections. Stimulation of plasmacytoid dendritic cells with certain CpG oligonucleotides results in the production of high levels of interferon- ⁇ . It is thought that CpG DNA interacts with TLR9 in the endosomal compartment. Recently, it has been demonstrated that murine plasmacytoid dendritic cells can produce high levels of IFN- ⁇ following stimulation with Guanidine and Uracil-rich sequences of single stranded (ss) RNA (Diebold et al Science 2004, 303, 1529).
• ss single stranded
• TLR7 in mice. Like TLR9, it is thought that TLR7 interacts with pathogen associated molecular patterns in endosomal compartments. The cellular location of TLR7, i.e. in the endosomal compartment, prevents activation by 'self ssRNA in the cytosol. However, it is generally accepted that ssRNA alone is unable to effectively stimulate IFN- ⁇ production from plasmacytoid dendritic cells. This is because ssRNA is particularly susceptible to nuclease attack, and also because uptake of ss-RNA's across plasma membranes is particularly poor.
• Such a means for stabilising the ss-RNA should protect the RNA from nuclease attack whilst maintaining its immunostimulatory properties.
• the means for stabilising the ss-RNA should ideally be in a form that it complementary with existing means for delivering immunogenic compounds, such that the generic immune response elicited by ss-RNA does not interfere with any specific therapies that may be administered or co-administered.
• compositions comprising ss-RNA which has been microencapsulated in the presence of a stabilising agent successfully stabilises and protects ss-RNA and also stimulates an increased cytokine response over other generic therapeutic agents.
• the composition of the present invention stimulates levels of IFN- ⁇ and IL-12. which are at least equivalent, if not superior, to those stimulated by ss-RNA condensed with commonly utilised in vitro transfection reagents (such as poly ethylene imine, hereinafter "PEI").
• PEI poly ethylene imine
• the particle size of the microparticulate formulation can be optimised depending on the required route of administration.
• the microparticles of the present invention may be formed so as to provide an average particle size within the range perceived to be optimal for delivery to the lower respiratory tract, i.e. 1-1 O ⁇ m.
• the microparticle and pharmaceutical compositions of the present invention stimulate production of cytokines in a host cell and, as such, may be used as a generic immunotherapy for a wide range of conditions and infections. This is particularly advantageous when a specific therapy is not known or is unavailable.
• a further advantage of the invention is that the composition optionally comprises specific therapeutic agents such that a generic and a specific immune response may be elicited in a compromised individual to whom the composition is administered.
• the microparticle composition of the present invention has the added advantage in that it may be stored as a dry powder for extended periods of time (at least several months)without loss of biological potency. After storage, the composition may be administered directly as a dry powder, for example by inhalation, or re-hydrated in a pharmaceutically acceptable solvent or buffer, as are known in the art, and administered parenterally, as required.
• compositions of the present invention may also be useful in eliciting a cytotoxic T- lymphocyte (CTL) response, which is particularly important for the clearance of intracellular pathogens and cancerous cells.
• CTL cytotoxic T- lymphocyte
• This feature of the composition highlights a particular advantage of the invention because, in light of the importance of IFN- ⁇ in the induction of CTL responses, it can provide a vaccine delivery system capable of inducing a CTL response. Such a vaccine delivery system is particularly suitable for tumour immunotherapy.
• a microparticle composition comprising a biodegradable polymer, an immunogenic single-stranded ribonucleic acid (hereinafter "ss-RNA”) material, a biologically active macromolecule and a stabilising agent wherein the biologically active macromolecule, the single-stranded ribonucleic acid (ss-RNA) and the stabilising agent are encapsulated inside and/or within the biodegradable polymer to provide a free outer surface of the microparticle.
• ss-RNA immunogenic single-stranded ribonucleic acid
• the outer surface of the microparticle is essentially free of the entrapped components, it is inevitable that a small proportion of each of the ss-RNA, the biologically active macromolecule and the stabilising agent may be present of the surface of the microparticle.
• the outer surface of the microparticles are substantially free of the entrapped components. Therefore, as used herein, "free outer surface” relates to the outer surface of microparticles which comprise no adsorbed components directly after formation.
• microparticles with such free outer surfaces may be subjected to processes which result in other materials, e.g. pharmaceutical compounds, macromolecules and nucleic acids, becoming adsorbed thereto.
• absorbed components relates to entrapped materials which may be partially present at the microparticle surface, as a result of the microparticle formation process and “adsorbed components” relates to materials which are adsorbed on to the outer surface of the microparticle, after it has been formed.
• microparticle refers to a particle of from about 10 nm to about 100 ⁇ m in diameter, preferably in the range of from 200 nm to 30 ⁇ m and more preferably in the range of from 500 nm to 10 ⁇ m in diameter. Microparticle size is readily determined by techniques well known in the art, such as laser diffractometry or scanning electron microscopy, and is commonly quoted as an average diameter. The terms particle, particulate, microparticle, microparticulate and microsphere may be used interchangeably and all fall within the above definition of microparticle.
• biodegradable polymer which is biocompatible may be used to form the microparticles of the present invention but it is preferred that a polymer which is known to degrade in mammalian tissue and which is suitable for pharmaceutical administration is used.
• biodegradable polymers include, but are not limited to, aliphatic polyesters, polymers derived from a poly( ⁇ -hydroxy acid) such as poly(lactide) ("PLA”), or a copolymer of D, L-lactide and glycolide or glycolic acid, such as poly(D,L- lactide-co-glycolide (“PLG” or "PLGA”) or a polyglycolide, a polycaprolactone and copolymers thereof. It is preferred that the biodegradable polymer is a poly(lactide).
• the ss-RNA material encapsulated within the microparticles can be any single stranded sequence of RNA which is capable of stimulating or enhancing an immune response, particularly by stimulating production of proinflammatory cytokines, such as Tumour- Necrosis Factor (TNF- ⁇ ) and /or anti-viral cytokines, such as INF- ⁇ , INF- ⁇ , or IL-12. It is preferred that ss-RNA stimulates the production and secretion of INF- ⁇ .
• proinflammatory cytokines such as Tumour- Necrosis Factor (TNF- ⁇ ) and /or anti-viral cytokines, such as INF- ⁇ , INF- ⁇ , or IL-12.
• TNF- ⁇ Tumour- Necrosis Factor
• anti-viral cytokines such as INF- ⁇ , INF- ⁇ , or IL-12. It is preferred that ss-RNA stimulates the production and secretion of INF- ⁇ .
• INF- ⁇ may be produced by many mechanisms, but it is preferred that the ss-RNA is chosen such that it stimulates production of the cytokine by interacting with and stimulating Toll-Like Receptors (TLR) of dendritic cells in a mammalian host. It will also be understood by those skilled in the art that different TLRs may facilitate the secretion of INF- ⁇ , but it is preferred that the ss- RNA stimulates TLR-7 and/or TLR-8, which are likely to be involved in cytokine expression in humans. Suitable ss-RNA sequences are those which have a high proportion of a single base, that is, sequences which contain regions which are rich in either A, U, C or G.
• the ss-RNA has a G-rich or a U-rich sequence.
• Preferred examples of ss- RNA include polyuridylic acid and polyguanylic acid. It is more preferred that the ss- RNA is polyuridylic acid.
• Microencapsulation of the ss-RNA is preferably performed in the presence of a biologically active macromolecule.
• macromolecules include therapeutic agents known to elicit generic immune responses, such as a oligodeoxynucleotides, CpG oligonucleotides, polypeptides and proteins and also substances capable of providing a specific therapeutic effect, such as agents which elicit a specific immune effect against a known pathogen, such as a pathogen-specific antigen or, in the alternative, substances which elicit a specific immune effect against an antigen expressed on a tumour or cancerous cell.
• therapeutic agents known to elicit generic immune responses such as a oligodeoxynucleotides, CpG oligonucleotides, polypeptides and proteins
• substances capable of providing a specific therapeutic effect such as agents which elicit a specific immune effect against a known pathogen, such as a pathogen-specific antigen or, in the alternative, substances which elicit a specific immune effect against an anti
• antigen means a molecule which contains one or more epitopes capable of stimulating a host's immune system to make an antigen-specific immune response when the antigen is present or to elicit a humoral antibody response.
• antigen denotes both sub-unit antigens and killed, attenuated or inactivated bacteria, viruses and other microbes.
• Antibodies and fragments of antibodies which can mimic an antigen or an antigenic determinant are also include in the definition of antigen.
• the microparticle composition comprises an antigen specific to a bacterial pathogen, for example recombinant Protective Antigen (rPA) of Bacillus anthracis or F1 and or V antigens from Yersinia pestis but it will be understood by those skilled in the art that any known antigen may be formulated into the microparticle composition.
• rPA recombinant Protective Antigen
• This embodiment is particularly useful for the treatment of bacterial infections, such as anthrax, plague, melioidosis, glanders, chlamydia and the like but also for the treatment of viral, fungal and parasitic infections, provided a suitable antigen or antigen-mimic is available.
• the stabilising agent of the microparticle formulation can be anyone selected from the wide range of stabilising agents known in the technical field.
• Stabilising agents include but are not limited to detergents, surfactants, dispersing agents, suspending agents and emulsion stabilisers.
• Preferred examples of stabilising agents include lipids and surfactants.
• the stabilising agent selected is a pharmaceutically acceptable agent, such that stabilising agents which may be toxic when administered in-vivo can be avoided.
• the stabilising agent is capable of forming a complex with the ss-RNA. Such complexes may be formed by direct covalent attachment of the stabilising agent to the ss-RNA, for example as a result of a condensation reaction or alternatively the complexes may be formed by electrostatic, ionic or hydrophobic interactions.
• the stabilising agent is positively charged, so as to effect an electrostatic interaction with the ss-RNA.
• Suitable examples of such stabilising agents are cationic polymers and/or cationic lipids.
• Preferred examples are cationic lipids such as cetyl trimethyl ammonium bromide (hereinafter "CTAB”), dimethyl dioctodecyl ammonium bromide (“DDA”) and N-[1-(2,3- dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (“DOTAP”) and the like.
• CTAB cetyl trimethyl ammonium bromide
• DDA dimethyl dioctodecyl ammonium bromide
• DOTAP N-[1-(2,3- dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride
• Suitable amounts of stabilising agent can be routinely determined by those skilled in the art, but it is preferred that the mass ratio of ss-RNA to biodegradable polymer to stabilising agent is in the range of from about 1:8:6 to about 1 :15:12 and more preferably the mass ratio of components is approximately 2:25:18.
• the selection and amount of stabilising agent may affect the overall charge of the microparticles formed in the presence of said stabilising agents such that the pharmaceutical composition may have a net negative or positive charge. It is preferred that the composition has a net positive charge, as measured by a suitable charge-measuring devices such as a ZetasizerTM, which measures zeta potential, the electrical potential that exists across the interface of all solids and liquids. It is further preferred that the measured zeta potential of the resulting composition is in the range of from about 0 to 100 mV, more preferably in the range of 20 to 80 mV and even more preferably in the range of 30 to 60 mV.
• a suitable charge-measuring devices such as a ZetasizerTM, which measures zeta potential, the electrical potential that exists across the interface of all solids and liquids. It is further preferred that the measured zeta potential of the resulting composition is in the range of from about 0 to 100 mV, more preferably in the range of 20 to 80
• the inventors have found that pharmaceutical compositions with zeta potential of around 50 mV are particularly effective in stimulating production of INF- ⁇ .
• the microparticle composition ideally comprises microparticles that are of a size which enables efficient administration and transport into the immune system, and which are particularly suitable for inhalational administration. It is preferred that the microparticles have a mean diameter in the range of 0.1 to 5 ⁇ m, more preferably 0.2 to 4 ⁇ m. It is most preferred that the microparticles have a mean diameter of approximately 1 ⁇ m.
• microparticles are suitably formulated into a pharmaceutical composition by combining the microparticles with pharmaceutically acceptable adjuvants and/or excipients, such as binders, fillers, diluents, lubricants, colours, sweeteners, dispersing agents and the like.
• pharmaceutically acceptable adjuvants and/or excipients such as binders, fillers, diluents, lubricants, colours, sweeteners, dispersing agents and the like.
• compositions may be formulated to provide a means of co-administering the microparticles with another therapeutic agent or adjuvant.
• the free outer surface of the microparticles provide a convenient location for the adsorption of further therapeutic agents, such as additional antigens, immunogenic proteins and polypeptides, nucleic acids such as CpG oligonucleotides and DNA vectors.
• additional therapeutic agents can be used to decorate the free outer surface of the microparticles to provide an enhanced immune response.
• step (c) adding the emulsion from step (b) to a solution containing the stabilising agent to form a double emulsion;
• the ss-RNA for use in the method is selected from the list already described herein and is conveniently dissolved in an aqueous solution, for example distilled water or aqueous buffer, and the biodegradable polymer dissolved in a water-immiscible solvent, such as an organic solvent, e.g. dichloromethane, but it will be understood by those skilled in the art that any combination of solvents may be used provided that they are capable of forming an emulsion when mixed.
• aqueous solution for example distilled water or aqueous buffer
• a water-immiscible solvent such as an organic solvent, e.g. dichloromethane
• the stabilising agent may be selected from those stabilising agents already described above may be dissolved in any solvent such that a double-emulsion is formed when the solution of the stabilising agent is added to the first emulsion, that is, the emulsion created in step (b).
• an aqueous or water-miscible solvent is used to dissolve the stabilising agent, in step (c).
• the first emulsion that is, the emulsion created by step (b) is added to the solution of the stabilising agent in step (c).
• the first emulsion that is, the emulsion created by step (b) is added to the solution of the stabilising agent in step (c).
• the emulsion created by step (b) is added to the solution of the stabilising agent in step (c).
• the emulsion from step (b) is added to the solution of the stabilising agent with mixing since the inventors have found that this provides better resulting microparticles.
• the emulsion from step (b) is added drop-wise to the solution of the stabilising agent with vigorous mixing.
• the solvent removal step (c) may be effected by any conventional means, such as constant stirring, vacuum or heat evaporation and the resulting microparticles collected by, for example, filtration or centrifugation. It is more preferred that the microparticles are collected by ultracentrifugation.
• the microparticles may then be collected and used directly or subjected to further treatments, processing or formulation, such as combining with pharmaceutically acceptable compounds to form a pharmaceutical composition. Although further processing may be desirable for some applications, it may, inmost cases, be unnecessary as the resulting microparticles are of a size which are efficacious when used without further processing.
• Microparticle compositions prepared according to the method of the present invention may be further subjected to a lypophilisation step, such that they can be stored for extended periods as a dry powder.
• a lypophilisation step such that they can be stored for extended periods as a dry powder.
• the inventors have found that such lyophilised compositions are stable for several months and have the advantage that they can be used directly as dry powder, for mucosal administration via, for example, a conventional inhaler device.
• the dry powders may be rehydrated as and when required, which is particularly advantageous for the preparation of compositions which are suitable for parenteral administration.
• Figure 1 shows particle size distribution graphs of RNA loaded microparticles, prepared using polyvinyl alcohol (PVA) or N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) as stabilising agents, as determined using laser diffraction measurements. Data are representative of three separate experiments.
• PVA polyvinyl alcohol
• DOTAP N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride
• FIG. 2 shows scanning electron micrographs of poly-U loaded polylactide microparticles prepared using polyvinyl alcohol (PVA) or N-[1-(2,3-Dioleoyloxy)propyl]- N.N.N-trimethylarnmonium chloride (DOTAP) as stabilising agents.
• PVA polyvinyl alcohol
• DOTAP N-[1-(2,3-Dioleoyloxy)propyl]- N.N.N-trimethylarnmonium chloride
• Figure 3 shows interferon-alpha levels in supernatants from bulk cultures of Flt3L expanded bone marrow derived dendritic cells following overnight stimulation with a range of concentrations of poly-U in solution (PoIy-U FREE), poly-U encapsulated in polylactide microparticles (Poly-U in MS), empty polylactide microparticles (Empty MS) and poly-U condensed with PEI (Poly-U PEI).
• Polylactide microparticles were prepared using either N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) or polyvinyl alcohol (PVA) as a stabiliser.
• DOTAP N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride
• PVA polyvinyl alcohol
• Figure 4 shows TNF-alpha levels in supernatants from bulk cultures of Flt3L expanded bone marrow derived dendritic cells following overnight stimulation with a range of concentrations of poly-U in solution (Poly-U FREE), poly-U encapsulated in polylactide microparticles (Poly-U in MS), empty polylactide microparticles (Empty MS) and poly-U condensed with PEI (Poly-U PEI).
• Polylactide microparticles were prepared using either N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-t ⁇ methylammonium chloride (DOTAP) or polyvinyl alcohol (PVA) as a stabiliser.
• DOTAP N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-t ⁇ methylammonium chloride
• PVA polyvinyl alcohol
• FIG. 5 shows IL-12 p40 levels in supematants from bulk cultures of Flt3L expanded bone marrow derived dendritic cells following overnight stimulation with a range of concentrations of poly-U in solution (PoIy-U FREE), poly-U encapsulated in polylactide microparticles (Poly-U in MS), empty polylactide microparticles (Empty MS) and poly-U condensed with PEI (Poly-U PEI).
• Polylactide microparticles were prepared using either N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride (DOTAP) or polyvinyl alcohol (PVA) as a stabiliser. For comparison, cells were also cocultured with 1 nmol CpG. Data are means ( ⁇ SD) of triplicate microcultures and are representative of three separate experiments.
• DOTAP N-[1-(2,3-Dioleoyloxy)propyl]-N,N,N-trimethylammonium chloride
• PVA polyvinyl alcohol
• Figure 6 shows cytokine secretion following overnight stimulation of Flt-3L expanded bone marrow dedritic cells (BMDC) with microencapsulated OVA, microencapsulated poly-U, comicroencapsulated OVA and poly-U, microencapsulated OVA with surface adsorbed CpG, CpG and OVA in solution or media only.
• Results are means ( ⁇ SD) of three separate experiments. * denotes statistically significant differences (P ⁇ 0.05) as compared with microencapsulated OVA treatment.
• Figure 7 shows serum anti-OVA IgG titres following subcutaneous immunisation of BALB/c mice with microencapsulated OVA, comicroencapsulated OVA and poly-U, microencapsulated OVA with surface adsorbed CpG, CpG and OVA in solution or poly-U and OVA in solution. Results are means ( ⁇ SD) with six mice per treatment group. * denotes statistically significant differences (P ⁇ 0.05) as compared with naive controls.
• Figure 8 shows OVA specific IFN- ⁇ and IL-4 ELISPOTS following subcutaneous immunisation of BALB/c mice with microencapsulated OVA, comicroencapsulated OVA and poly-U, microencapsulated OVA with surface adsorbed CpG, CpG and OVA in solution or poly-U and OVA in solution. Results are means ( ⁇ SD) with six mice per treatment group. * denotes significant differences (P ⁇ 0.05) as compared with naive controls. ** denotes significant difference as compared with all other treatments (P ⁇ 0.05).
• Figure 9 shows FACS analysis of tetramer stained lymph node cells pooled from six mice immunised with comicroencapsulated OVA and poly-U (top pannel) or na ⁇ ve mice (lower panel). Mice immunised with comicroencapsulated OVA and poly-U had a greater number of CD8 cells with bound tetramer, as evidenced by an increased FL2 signal.
• Polyuredylic acid (poly-U) (Sigma, Dorset UK) was encapsulated in poly-lactide microparticles. Briefly, 10 mg of poly-U was suspended in 0.5 ml of an aqueous solution of polyvinyl alcohol (PVA) 13-23kDa (1.5 % w/v) (Sigma, Dorset UK) and vigorously mixed with 125 mg of polylactide (PLA) dissolved in 9 ml of dicholoromethane (DCM) (Sigma, Dorset UK) using a Silverson homogeniser (Silverson, Bucks. UK).
• PVA polyvinyl alcohol
• DCM dicholoromethane
• the resultant emulsion was added, drop-wise, into a vigorously stirred secondary aqueous phase (90 ml) containing 3.0 % w/v PVA 13-23kDa. Following solvent evaporation, hardened polymeric microparticles were harvested by ultracentrifugation prior to lyophilisation (Edwards, Crawley UK).
• Ovalbumin Ovalbumin (OVA) (Sigma, Dorset, UK) was encapsulated in polylactide microparticles as described in example 2, by co-addition of 5 mg OVA and 10 mg PoIy-U in 0.5 ml of distilled water.
• RNA was successfully extracted from both PVA- and DOTAP- stabilised microparticles, as confirmed by NanoDrop technology (results not shown).
• Ovalbumin Ovalbumin
• Microencapsulated OVA was prepared as described in example 3 in the absence of poly-U .
• Cationic microparticles were prepared using a modified single emulsion solvent evaporation method. 125 mg of PLA dissolved in 9 ml of DCM (Sigma, Dorset UK) was vigorously mixed with a 90 ml volume of 0.1% w/v DOTAP using a Silverson homogeniser (Silverson, Bucks. UK). Following solvent evaporation, hardened polymeric microparticles were harvested by ultracentrifugation prior to lyophilisation
• Ovalbumin loaded microparticles prepared as described in example 3, were 'decorated' with CpG (MWG-BIOTECH Ltd, Bucks, UK) by adsorbing CpG to the surface of the microparticles. 7 mg of OVA loaded microparticles were suspended in 0.7 ml of a 800 ⁇ g ml-1 solution of CpG DNA (ggTGCATCGATGCAgggggG) in sterile saline. Particles were incubated in this solution for 20 minutes at room temperature.
• Microparticles prepared as described above in Examples 1 , 2, 3 and 4 were sized using a Mastersizer 2000 (Malvern Instruments, Malvern, UK). Laser diffraction measurements revealed that loaded polylactide microparticles had a size distribution of around 1 ⁇ m, as shown in Figure 1. Both PVA stabilised (Fig. 1A) and DOTAP stabilised (Fig. 1B) formulations had similar size distributions.
• FIG. 2 shows that both PVA stabilised (Fig. 2A) and DOTAP stabilised (Fig. 2B) formulations had similar size distributions and morphology.
• PVA polyvinyl alcohol
• DOTAP N-f1-(2.3-Dioleoyloxy)propyll-N.N.N- trimethylammonium chloride
• BMDCs bone marrow derived plasmacytoid and myeloid dendritic cells
• Tibiae and fibulas were removed from the rear legs and then placed in sterile culture media (RPMI-1640) (Sigma, UK) supplemented with 10% heat inactivated foetal bovine serum (FBS) (Sigma, UK); 1% penicillin / streptomycin / glutamine (Sigma, UK) and 50 ⁇ M 2-Mercaptoethanol (2-ME) (Sigma, UK) for transport to a class Il microbiological safety cabinet.
• FBS foetal bovine serum
• 2-ME 2-Mercaptoethanol
• Cell concentration was adjusted to 2 x 1O 6 .mL "1 and the media further supplemented with lOOng.mL '1 murine Fms-like tyrosine kinase receptor-3 ligand factor (Flt3L) (R&D Systems, Oxford, UK).
• the cells were plated out using 6-well tissue culture plates (Sterilin, Stone, UK) and incubated at 37 0 C in a fully humidified environment in the presence of 5% CO 2 . After 5 days, half of the medium was removed and replaced with fresh Flt3L supplemented media. After 10 days, cells were washed and re-seeded at 2x 1O 6 .mL "1 in sterile flat-bottomed 96-well tissue culture plates (Sterilin, Stone, UK).
• Dendritic cell activation assays PoIv-U loaded microspheres Bulk cultures of C57B1J6 Flt3L BMDCs, prepared as described in example 11, were cocultured with escalating doses of poly-U in sterile 96 well flat-bottomed plates. DCs were also cocultured with escalating doses of polylactide microparticle encapsulated ssRNA, as described in Examples 1 and 2. The mass of microencapsulated poly-U added to the cultures was comparable to the doses of free ssRNA used (based on a 100 % theoretical loading efficiency; i.e. an assumption that 100 % of the ssRNA used in the formulation process was incorporated).
• DCs were also cocultured with escalating doses of PEI condensed ssRNA, prepared as described in Example 10.
• a positive control 1nmol of a K- type (conventional) CpG (ODN1668: tccatgacgttcctgatgct) and a A/D-type CpG (D 19: ggTGCATCGATGCAgggggG) were used.
• Cells were cocultured with the various stimulents for 18 hours. Culture supernatants were obtained by centrifugation of the cells and formulations for 10 minutes at 10000 rpm.
• DC cultures stimulated with poly U and CpG were quantified using commercially available ELISA kits (R&D systems, Oxford UK).
• poly-U loaded polylactide microparticles prepared using DOTAP as a stabilising agent, were potent stimulators of IFN- ⁇ production.
• the levels of IFN- ⁇ stimulated by the poly-U loaded DOTAP stabilised microparticles was significantly (P ⁇ 0.001) higher as compared with DC exposed to un-formulated (free) poly U and comparable with that engendered by stimulation with PEI-condensed poly-U.
• coculture of DC with poly-U loaded polylactide microparticles, prepared using PVA as a stabilising agent resulted in low levels of IFN- ⁇ production.
• Free poly-U and poiylactide microparticle encapsulated poly-U stimulated TNF- ⁇ production by bulk cultures of Flt3L expanded bone marrow derived dendritic cells as shown in Figure 4.
• Highest levels of TNF- ⁇ were induced by stimulation with poly-U loaded poiylactide microparticles, prepared using PVA as a stabilising agent.
• poly-U loaded poiylactide microparticles, prepared using DOTAP as a stabilising agent were less efficient stimulators of TNF- ⁇ production.
• PoIy-U condensed with PEI failed to elicit the production of significant levels of TNF- ⁇ .
• Dendritic Cell Activation Assays OVA-loaded microparticles.
• BMDC bone marrow-derived dendritic cells
• TNF- ⁇ levels of TNF- ⁇ in supernatants was highest when cells were stimulated with OVA loaded CpG decorated microparticles (P ⁇ 0.05). Stimulation of cells with soluble antigen and CpG also resulted in significant TNF- ⁇ production relative to other treatments (P ⁇ 0.05).
• IL-12p40 concentration in culture supernatants was greatest when BMDC were stimulated with OVA loaded microparticles surface decorated with CpG, or CpG and OVA in solution.
• stimulation with microparticles containing poly-U caused enhanced levels of IL-12 p40 secretion (P ⁇ 0.05).
• mice were immunised by subcutaneous injection into the flank region on days 0, 14 and 28 of the experiment. Microparticle loading values were assumed to be 100 % that of the maximum theoretical value. Hence, mice dosed with soluble antigen / TLR agonist received either the same, or higher, doses as compared with mice immunised with microparticulate material.
• a sixth group acted as naive controls.
• mice immunised according to example 14 were bled on day 32 to obtain serum. Serum was analyzed for anti-OVA antibodies using standard ELISA methodology. Briefly, individual serum samples were aliqoted to microtitre plates pre-coated with OVA (5 ⁇ g ml "1 in PBS). Binding of serum antibody was detected with peroxidase-labelled secondary antibody to mouse IgGI and lgG2a (Harlan-SeraLab, Crawley Down, UK).
• each subclass specific conjugate may not be equally reactive with its subclass molecule, to facilitate a comparison of one subclass titer with another, standard solutions (Harlan- SeraLab, Crawley Down, UK) of each subclass antibody in the range of 0.2-50.0 ng ml "1 were assayed.
• the standard curves generated enabled determination of the mean concentration of each IgG subclass in serum derived from the various treatment groups.
• a statistical test (Dunnett) was used to establish if any of the immunisation treatments had stimulated higher levels of specific antibody as compared with control (na ⁇ ve) animals.
• mice injected with OVA loaded microparticles decorated with CpG had significant anti-OVA antibody titres but mice injected with microparticles containing OVA and poly U showed an amplified antibody response, as shown in Figure 7.
• IgGI was the dominant anti-OVA antibody detected.
• Injection of mice with OVA loaded microparticles or soluble OVA admixed with CpG served to elicit a specific serum anti-OVA IgGI response in some mice, although within group variation entailed that the effect was not statistically significant as compared with naive animals.
• Injection of a solution of OVA admixed with poly-U induced negligible levels of serum anti-OVA IgG.
• Anti-OVA lgG2a was detected only in mice that had been immunised with antigen co-formulated with CpG or poly U.
• mice immunised according to example 14 were killed and individual (not pooled) spleens removed. Single cell suspensions were prepared in supplemented RPMI-1640.
• IFN- ⁇ and IL-4 ELISPOT kits (BD Biosciences, Oxford UK) were used according to the manufacturer's guidelines. In brief, 96-well nitrocellulose bottomed-plates were coated with 10O ⁇ l of 5 ⁇ g ml "1 capture antibody in PBS and incubated overnight at 4 0 C. Free binding sites were blocked with 200 ⁇ l of supplemented RPMI for 2 hours. Spleen cell concentrations were adjusted to 2.5 x10 6 cells ml "1 and added to the appropriated well. Analyses were always conducted on cells from individual mice in each treatment group.
• Cells were stimulated in triplicate with either 5 ⁇ g ml "1 OVA in supplemented RPM1 1640, supplemented RPMI 1640 alone as a negative control or 2.5 ⁇ g ml "1 Concanavalin A (Sigma, Dorset, UK) as a positive control overnight.
• the cells were removed by washing initially with dH 2 O and then with PBS containing 0.05% Tween-20.
• the site of cytokine secretion was detected with a biotin-labeled anti-mouse cytokine antibody and horseradish peroxidase-conjugated streptavidin.
• the enzyme reaction was developed using 3-amino-9-ethylcarbazole (AEC) substrate reagent set (Sigma, Dorset, UK). Spot forming cell numbers were determined using a dissecting light microscope (Zeiss Stemi 2000) and expressed relative to 1x10 6 cells plated. Statistical differences were established using ANOVA and Student-Newman-Keuls tests.
• AEC 3-amino-9-ethylcarbazole
• mice immunised according to example 14 were killed and Inguinal lymph nodes draining the site of injection were removed and pooled for tetramer analysis.
• Single cell suspensions were prepared in supplemented RPMI-1640.
• Single cell suspensions of lymph node cells were stimulated with OVA (50 ⁇ g ml-1) for 72 hours at 37 0 C in a humidified 5% CO 2 environment.
• OVA 50 ⁇ g ml-1
• cells were isolated from the culture plates and stained using the iTAgTM MHC Class I Murine Tetramer - SA - PE kit (Beckman Coulter, Immunomics, France).
• FITC coupled CD 3 (Pharmingen, BD Biosciences, UK) and Cy 5.5 coupled CD 8 (Pharmingen, BD Biosciences, UK) antibodies were also used to stain the cells. All staining and fixation procedures were carried out in accordance with the manufacturer's instructions. After fixing, cells were analysed on a BD FACScan flow cytometer. Corresponding isotype controls were used to establish quadrants and / or regions for analysis. Analyses were performed using Cell Quest Pro flow cytometry analysis software.
• Tetramer staining of lymph node cells from immunised mice revealed that injection of co- microencapsulated OVA and poly U can engender antigen specific CD8 + T-cells, as shown in Figure 9.
• Mice immunised with co-micorencapsulated OVA and PoIy-U (Fig. 9A) had a greater number of CD8 cells with bound tetramer, as evidenced by the increased FL2 signal.
• Figure 9B shows a profile obtained from na ⁇ ve mice.

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