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  • A61K9/1272—Non-conventional liposomes, e.g. PEGylated liposomes or liposomes coated or grafted with polymers comprising non-phosphatidyl surfactants as bilayer-forming substances, e.g. cationic lipids or non-phosphatidyl liposomes coated or grafted with polymers
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  • C12N2760/00011—Details
  • C12N2760/18011—Paramyxoviridae
  • C12N2760/18511—Pneumovirus, e.g. human respiratory syncytial virus
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  • C12N2770/00011—Details
  • C12N2770/36011—Togaviridae
  • C12N2770/36111—Alphavirus, e.g. Sindbis virus, VEE, EEE, WEE, Semliki
  • C12N2770/36134—Use of virus or viral component as vaccine, e.g. live-attenuated or inactivated virus, VLP, viral protein
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  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
  • Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
  • Y02A50/30—Against vector-borne diseases, e.g. mosquito-borne, fly-borne, tick-borne or waterborne diseases whose impact is exacerbated by climate change

Definitions

• This invention is in the field of non- viral delivery of RNA for immunisation.
• nucleic acids for immunising animals has been a goal for several years.
• Various approaches have been tested, including the use of DNA or RNA, of viral or non-viral delivery vehicles (or even no delivery vehicle, in a "naked” vaccine), of replicating or non-replicating vectors, or of viral or non- viral vectors.
• RNA encoding an immunogen is delivered in a liposome for the purposes of immunisation.
• the liposome includes lipids which have a pKa in the range of 5.0 to 7.6.
• the lipid with a pKa in this range has a tertiary amine; such lipids behave differently from lipids such as DOTAP or DC-Choi, which have a quaternary amine group.
• DOTAP lipid such as DOTAP
• the inventors have found that liposomes formed from quaternary amine lipids (e.g. DOTAP) are less suitable for delivery of immunogen-encoding RNA than liposomes formed from tertiary amine lipids (e.g. DLinDMA).
• the invention provides a liposome having a lipid bilayer encapsulating an aqueous core, wherein: (i) the lipid bilayer comprises a lipid having a pKa in the range of 5.0 to 7.6, and preferably having a tertiary amine; and (ii) the aqueous core includes a RNA which encodes an immunogen.
• the lipid bilayer comprises a lipid having a pKa in the range of 5.0 to 7.6, and preferably having a tertiary amine
• the aqueous core includes a RNA which encodes an immunogen.
• the invention also provides a process for preparing a RNA-containing liposome, comprising steps of: (a) mixing RNA with a lipid at a pH which is below the lipid's pKa but is above 4.5, to form a liposome in which the RNA is encapsulated; and (b) increasing the pH of the resulting liposome- containing mixture to be above the lipid's pKa.
• the liposome The liposome
• the invention utilises liposomes in which immunogen-encoding RNA is encapsulated.
• the RNA is (as in a natural virus) separated from any external medium by the liposome's lipid bilayer, and encapsulation in this way has been found to protect RNA from RNase digestion.
• the liposomes can include some external RNA (e.g. on their surface), but at least half of the RNA (and ideally all of it) is encapsulated in the liposome's core. Encapsulation within liposomes is distinct from, for instance, the lipid/RNA complexes disclosed in reference 1.
• RNA- containing aqueous core can have an anionic, cationic or zwitterionic hydrophilic head group.
• Liposomes of the invention comprise a lipid having a pKa in the range of 5.0 to 7.6, and preferred lipids with a pKa in this range have a tertiary amine.
• they may comprise l ,2-dilinoleyloxy-N,N-dimethyl-3-aminopropane (DLinDMA; pKa 5.8) and/or 1 ,2- dilinolenyloxy-N,N-dimethyl-3-aminopropane (DLenDMA).
• Another suitable lipid having a tertiary amine is l ,2-dioleyloxy-N,Ndimethyl-3-aminopropane (DODMA). See Figure 3 & ref. 2.
• Some of the amino acid lipids of reference 3 may also be used, as can certain of the amino lipids of reference 4. Further useful lipids with tertiary amines in their headgroups are disclosed in reference 5, the complete contents of which are incorporated herein by reference.
• Liposomes of the invention can be formed from a single lipid or from a mixture of lipids, provided that at least one of the lipids has a pKa in the range of 5.0 to 7.6 (and, preferably, a tertiary amine). Within this pKa range, preferred lipids have a pKa of 5.5 to 6.7 e.g. between 5.6 and 6.8, between 5.6 and 6.3, between 5.6 and 6.0, between 5.5 and 6.2, or between 5.7 and 5.9.
• the pKa is the pH at which 50% of the lipids are charged, lying halfway between the point where the lipids are completely charged and the point where the lipids are completely uncharged.
• pKa measurement typically should be measured for the lipid alone rather than for the lipid in the context of a mixture which also includes other lipids (e.g. not as performed in reference 6, which looks at the pKa of a SNALP rather than of the individual lipids).
• a liposome of the invention is formed from a mixture of lipids
• the proportion of those lipids which have a pKa within the desired range should be between 20-80%) of the total amount of lipids e.g. between 30-70%), or between 40-60%>.
• useful liposomes are shown below in which 40%> or 60%> of the total lipid is a lipid with a pKa in the desired range.
• the remainder can be made of e.g. cholesterol (e.g. 35-50%> cholesterol) and/or DMG (optionally PEGylated) and/or DSPC.
• Such mixtures are used below.
• a liposome may include an amphiphilic lipid whose hydrophilic portion is PEGylated (i. e. modified by covalent attachment of a polyethylene glycol). This modification can increase stability and prevent non-specific adsorption of the liposomes.
• lipids can be conjugated to PEG using techniques such as those disclosed in reference 6 and 7. PEG provides the liposomes with a coat which can confer favourable pharmacokinetic characteristics.
• RNA particularly a self-replicating RNA
• a cationic lipid having a pKa in the range 5.0-7.6 and a PEGylated surface
• PEG poly(ethylene glycol)
• Various lengths of PEG can be used e.g. between 0.5-8kDa.
• Lipids used with the invention can be saturated or unsaturated.
• the use of at least one unsaturated lipid for preparing liposomes is preferred.
• Figure 3 shows three useful unsaturated lipids. If an unsaturated lipid has two tails, both tails can be unsaturated, or it can have one saturated tail and one unsaturated tail.
• a mixture of DSPC, DLinDMA, PEG-DMG and cholesterol is used in the examples.
• An independent aspect of the invention is a liposome comprising DSPC, DLinDMA, PEG-DMG & cholesterol.
• This liposome preferably encapsulates RNA, such as a self-replicating RNA e.g. encoding an immunogen.
• Liposomal particles are usually divided into three groups: multilamellar vesicles (MLV); small unilamellar vesicles (SUV); and large unilamellar vesicles (LUV).
• MLVs have multiple bilayers in each vesicle, forming several separate aqueous compartments.
• SUVs and LUVs have a single bilayer encapsulating an aqueous core; SUVs typically have a diameter ⁇ 50nm, and LUVs have a diameter >50nm.
• Liposomal particles of the invention are ideally LUVs with a diameter in the range of 50-220nm.
• compositions comprising a population of LUVs with different diameters: (i) at least 80% by number should have diameters in the range of 20-220nm, (ii) the average diameter (Zav, by intensity) of the population is ideally in the range of 40-200nm, and/or (iii) the diameters should have a polydispersity index ⁇ 0.2.
• the liposome/RNA complexes of reference 1 are expected to have a diameter in the range of 600-800nm and to have a high polydispersity.
• the liposome can be substantially spherical.
• the invention provides a process for preparing a RNA-containing liposome, comprising steps of: (a) mixing RNA with a lipid at a pH which is below the lipid's pKa but is above 4.5; then (b) increasing the pH to be above the lipid's pKa.
• a cationic lipid is positively charged during liposome formation in step (a), but the pH change thereafter means that the majority (or all) of the positively charged groups become neutral.
• This process is advantageous for preparing liposomes of the invention, and by avoiding a pH below 4.5 during step (a) the stability of the encapsulated RNA is improved.
• the pH in step (a) is above 4.5, and is ideally above 4.8. Using a pH in the range of 5.0 to 6.0, or in the range of 5.0 to 5.5, can provide suitable liposomes.
• the increased pH in step (b) is above the lipid's pKa.
• the pH is ideally increased to a pH less than 9, and preferably less than 8.
• the pH in step (b) may thus be increased to be within the range of 6 to 8 e.g. to pH 6.5+0.3.
• the pH increase of step (b) can be achieved by transferring the liposomes into a suitable buffer e.g. into phosphate-buffered saline.
• the pH increase of step (b) is ideally performed after liposome formation has taken place.
• RNA used in step (a) can be in aqueous solution, for mixing with an organic solution of the lipid (e.g. an ethanolic solution, as in ref. 11). The mixture can then be diluted to form liposomes, after which the pH can be increased in step (b).
• an organic solution of the lipid e.g. an ethanolic solution, as in ref. 11
• the invention is useful for in vivo delivery of RNA which encodes an immunogen.
• the RNA is translated by non-immune cells at the delivery site, leading to expression of the immunogen, and it also causes immune cells to secrete type I interferons and/or pro-inflammatory cytokines which provide a local adjuvant effect.
• the non-immune cells may also secrete type I interferons and/or pro-inflammatory cytokines in response to the RNA.
• RNA is +-stranded, and so it can be translated by the non-immune cells without needing any intervening replication steps such as reverse transcription. It can also bind to TLR7 receptors expressed by immune cells, thereby initiating an adjuvant effect.
• Preferred +-stranded RNAs are self-replicating.
• a self-replicating RNA molecule (replicon) can, when delivered to a vertebrate cell even without any proteins, lead to the production of multiple daughter RNAs by transcription from itself (via an antisense copy which it generates from itself).
• a self-replicating RNA molecule is thus typically a +-strand molecule which can be directly translated after delivery to a cell, and this translation provides a RNA-dependent RNA polymerase which then produces both antisense and sense transcripts from the delivered RNA.
• the delivered RNA leads to the production of multiple daughter RNAs.
• RNAs may be translated themselves to provide in situ expression of an encoded immunogen, or may be transcribed to provide further transcripts with the same sense as the delivered RNA which are translated to provide in situ expression of the immunogen.
• the overall results of this sequence of transcriptions is a huge amplification in the number of the introduced replicon RNAs and so the encoded immunogen becomes a major polypeptide product of the cells.
• a self-replicating activity is not required for a RNA to provide an adjuvant effect, although it can enhance post-transfection secretion of cytokines.
• the self-replicating activity is particularly useful for achieving high level expression of the immunogen by non-immune cells. It can also enhance apoptosis of the non-immune cells.
• One suitable system for achieving self-replication is to use an alphavirus-based RNA replicon. These +-stranded replicons are translated after delivery to a cell to give of a replicase (or replicase- transcriptase).
• the replicase is translated as a polyprotein which auto-cleaves to provide a replication complex which creates genomic— strand copies of the +-strand delivered RNA.
• strand transcripts can themselves be transcribed to give further copies of the +-stranded parent RNA and also to give a subgenomic transcript which encodes the immunogen. Translation of the subgenomic transcript thus leads to in situ expression of the immunogen by the infected cell.
• Suitable alphavirus replicons can use a replicase from a Sindbis virus, a semliki forest virus, an eastern equine encephalitis virus, a Venezuelan equine encephalitis virus, etc. Mutant or wild-type virus sequences can be used e.g. the attenuated TC83 mutant of VEEV has been used in replicons [12].
• a preferred self-replicating RNA molecule thus encodes (i) a RNA-dependent RNA polymerase which can transcribe RNA from the self-replicating RNA molecule and (ii) an immunogen.
• the polymerase can be an alphavirus replicase e.g. comprising one or more of alphavirus proteins nsPl, nsP2, nsP3 and nsP4.
• RNA molecule of the invention does not encode alphavirus structural proteins.
• a preferred self-replicating RNA can lead to the production of genomic RNA copies of itself in a cell, but not to the production of RNA- containing virions.
• the inability to produce these virions means that, unlike a wild-type alphavirus, the self-replicating RNA molecule cannot perpetuate itself in infectious form.
• alphavirus structural proteins which are necessary for perpetuation in wild-type viruses are absent from self-replicating RNAs of the invention and their place is taken by gene(s) encoding the immunogen of interest, such that the subgenomic transcript encodes the immunogen rather than the structural alphavirus virion proteins.
• RNA molecule useful with the invention may have two open reading frames.
• the first (5') open reading frame encodes a replicase; the second (3') open reading frame encodes an immunogen.
• the RNA may have additional ⁇ e.g. downstream) open reading frames e.g. to encode further immunogens (see below) or to encode accessory polypeptides.
• a self-replicating RNA molecule can have a 5' sequence which is compatible with the encoded replicase.
• Self-replicating RNA molecules can have various lengths but they are typically 5000-25000 nucleotides long e.g. 8000-15000 nucleotides, or 9000-12000 nucleotides. Thus the RNA is longer than seen in siRNA delivery.
• a RNA molecule useful with the invention may have a 5' cap ⁇ e.g. a 7-methylguanosine). This cap can enhance in vivo translation of the RNA.
• the 5' nucleotide of a RNA molecule useful with the invention may have a 5' triphosphate group. In a capped RNA this may be linked to a 7-methylguanosine via a 5'-to-5' bridge.
• a 5' triphosphate can enhance RIG-I binding and thus promote adjuvant effects.
• a RNA molecule may have a 3' poly-A tail. It may also include a poly-A polymerase recognition sequence (e.g. AAUAAA) near its 3' end.
• AAUAAA poly-A polymerase recognition sequence
• RNA molecule useful with the invention will typically be single-stranded.
• Single-stranded RNAs can generally initiate an adjuvant effect by binding to TLR7, TLR8, RNA helicases and/or PKR.
• RNA delivered in double-stranded form can bind to TLR3, and this receptor can also be triggered by dsRNA which is formed either during replication of a single-stranded RNA or within the secondary structure of a single-stranded RNA.
• RNA molecule useful with the invention can conveniently be prepared by in vitro transcription (IVT).
• IVT can use a (cDNA) template created and propagated in plasmid form in bacteria, or created synthetically (for example by gene synthesis and/or polymerase chain-reaction (PCR) engineering methods).
• a DNA-dependent RNA polymerase such as the bacteriophage T7, T3 or SP6 RNA polymerases
• Appropriate capping and poly-A addition reactions can be used as required (although the replicon's poly-A is usually encoded within the DNA template).
• RNA polymerases can have stringent requirements for the transcribed 5' nucleotide(s) and in some embodiments these requirements must be matched with the requirements of the encoded replicase, to ensure that the IVT -transcribed RNA can function efficiently as a substrate for its self-encoded replicase.
• the self-replicating RNA can include (in addition to any 5' cap structure) one or more nucleotides having a modified nucleobase.
• the RNA can comprise m5C (5-methylcytidine), m5U (5-methyluridine), m6A (N6-methyladenosine), s2U (2-thiouridine), Um (2'-0-methyluridine), mlA (1-methyladenosine); m2A (2-methyladenosine); Am (2'-0- methyladenosine); ms2m6A (2-methylthio-N6-methyladenosine); i6A (N6-isopentenyladenosine); ms2i6A (2-methylthio-N6isopentenyladenosine); io6A (N6-(cis-hydroxyisopentenyl)adenosine); ms2io6A (2-methylthio-N6-(cis-hydroxyisopenten
• cmnm5s2U 5-carboxymethylaminomethyl-2-thiouridine
• m62A N6,N6- dimethyladenosine
• Tm (2'-0-methylinosine
• m4C N4-methylcytidine
• m4Cm N4,2-0- dimethylcytidine
• hm5C 5-hydroxymethylcytidine
• cm3U (3-methyluridine)
• cm5U (5- carboxymethyluridine
• m6Am N6,T-0-dimethyladenosine
• rn62Am N6,N6,0-2- trimethyladenosine
• m2'7G N2,7-dimethylguanosine
• m2'2'7G N2,N2,7-trimethylguanosine
• m3Um 3,2T-0-dimethyluridine
• m5D 5-methyldihydrouridine
• 5-(Cl-C6 )-alkylcytosine 5-methylcytosine, 5-(C2-C6)-alkenylcytosine, 5-(C2-C6)-alkynylcytosine, 5-chlorocytosine, 5-fluorocytosine, 5-bromocytosine, N2-dimethylguanine, 7-deazaguanine, 8- azaguanine, 7-deaza-7-substituted guanine, 7-deaza-7-(C2-C6)alkynylguanine, 7-deaza-8-substituted guanine, 8-hydroxyguanine, 6-thioguanine, 8-oxoguanine, 2-aminopurine, 2-amino-6-chloropurine, 2,4-diaminopurine, 2,6-diaminopurine, 8-azapurine, substituted 7-deazapurine, 7-deaza-7-substituted purine, 7-deaza-8-sub
• a self-replicating RNA can include one or more modified pyrimidine nucleobases, such as pseudouridine and/or 5-methylcytosine residues.
• the RNA includes no modified nucleobases, and may include no modified nucleotides i.e. all of the nucleotides in the RNA are standard A, C, G and U ribonucleotides (except for any 5' cap structure, which may include a 7'-methylguanosine).
• the RNA may include a 5' cap comprising a 7'-methylguanosine, and the first 1, 2 or 3 5' ribonucleotides may be methylated at the 2' position of the ribose.
• a RNA used with the invention ideally includes only phosphodiester linkages between nucleosides, but in some embodiments it can contain phosphoramidate, phosphorothioate, and/or methylphosphonate linkages.
• a liposome includes fewer than 10 different species of RNA e.g. 5, 4, 3, or 2 different species; most preferably, a liposome includes a single RNA species i.e. all RNA molecules in the liposome have the same sequence and same length.
• RNA per liposome can vary.
• the number of individual self-replicating RNA molecules per liposome is typically ⁇ 50 e.g. ⁇ 20, ⁇ 10, ⁇ 5, or 1-4 per liposome.
• RNA molecules used with the invention encode a polypeptide immunogen. After administration of the liposomes the RNA is translated in vivo and the immunogen can elicit an immune response in the recipient.
• the immunogen may elicit an immune response against a bacterium, a virus, a fungus or a parasite (or, in some embodiments, against an allergen; and in other embodiments, against a tumor antigen).
• the immune response may comprise an antibody response (usually including IgG) and/or a cell-mediated immune response.
• the polypeptide immunogen will typically elicit an immune response which recognises the corresponding bacterial, viral, fungal or parasite (or allergen or tumour) polypeptide, but in some embodiments the polypeptide may act as a mimotope to elicit an immune response which recognises a bacterial, viral, fungal or parasite saccharide.
• the immunogen will typically be a surface polypeptide e.g. an adhesin, a hemagglutinin, an envelope glycoprotein, a spike glycoprotein, etc.
• Self-replicating RNA molecules can encode a single polypeptide immunogen or multiple polypeptides. Multiple immunogens can be presented as a single polypeptide immunogen (fusion polypeptide) or as separate polypeptides. If immunogens are expressed as separate polypeptides then one or more of these may be provided with an upstream IRES or an additional viral promoter element. Alternatively, multiple immunogens may be expressed from a polyprotein that encodes individual immunogens fused to a short autocatalytic protease ⁇ e.g. foot-and-mouth disease virus 2A protein), or as inteins.
• a short autocatalytic protease e.g. foot-and-mouth disease virus 2A protein
• the RNA encodes an immunogen.
• the invention does not encompass RNA which encodes a firefly luciferase or which encodes a fusion protein of E.coli ⁇ -galactosidase or which encodes a green fluorescent protein (GFP).
• GFP green fluorescent protein
• the RNA is not total mouse thymus RNA.
• the immunogen elicits an immune response against one of these bacteria:
• Neisseria meningitidis useful immunogens include, but are not limited to, membrane proteins such as adhesins, autotransporters, toxins, iron acquisition proteins, and factor H binding protein. A combination of three useful polypeptides is disclosed in reference 15.
• Streptococcus pneumoniae useful polypeptide immunogens are disclosed in reference 16. These include, but are not limited to, the RrgB pilus subunit, the beta-N-acetyl-hexosaminidase precursor (spr0057), spr0096, General stress protein GSP-781 (spr2021, SP2216), serine/threonine kinase StkP (SP1732), and pneumococcal surface adhesin PsaA.
• Streptococcus pyogenes include, but are not limited to, the polypeptides disclosed in references 17 and 18.
• Bordetella pertussis Useful pertussis immunogens include, but are not limited to, pertussis toxin or toxoid (PT), filamentous haemagglutinin (FHA), pertactin, and agglutinogens 2 and 3.
• Staphylococcus aureus Useful immunogens include, but are not limited to, the polypeptides disclosed in reference 19, such as a hemolysin, esxA, esxB, ferrichrome-binding protein (sta006) and/or the staOl l lipoprotein.
• Clostridium tetani the typical immunogen is tetanus toxoid.
• Cornynebacterium diphtheriae the typical immunogen is diphtheria toxoid.
• Haemophilus influenzae Useful immunogens include, but are not limited to, the polypeptides disclosed in references 20 and 21.
• Streptococcus agalactiae useful immunogens include, but are not limited to, the polypeptides disclosed in reference 17.
• Chlamydia trachomatis Useful immunogens include, but are not limited to, PepA, LcrE, ArtJ, DnaK, CT398, OmpH-like, L7/L12, OmcA, AtoS, CT547, Eno, HtrA and MurG ⁇ e.g. as disclosed in reference 22.
• LcrE [23] and HtrA [24] are two preferred immunogens.
• Chlamydia pneumoniae Useful immunogens include, but are not limited to, the polypeptides disclosed in reference 25.
• Helicobacter pylori Useful immunogens include, but are not limited to, CagA, VacA, NAP, and/or urease [26].
• Escherichia coli Useful immunogens include, but are not limited to, immunogens derived from enterotoxigenic E. coli (ETEC), enteroaggregative E. coli (EAggEC), diffusely adhering E. coli (DAEC), enteropathogenic E. coli (EPEC), extraintestinal pathogenic E. coli (ExPEC) and/or enterohemorrhagic E. coli (EHEC).
• ETEC enterotoxigenic E. coli
• EAggEC enteroaggregative E. coli
• DAEC diffusely adhering E. coli
• EPEC enteropathogenic E. coli
• ExPEC extraintestinal pathogenic E. coli
• EHEC enterohemorrhagic E. coli
• ExPEC strains include uropathogenic E.coli (UPEC) and meningitis/sepsis-associated E.coli (MNEC).
• UPEC uropathogenic E.coli
• MNEC meningitis/sepsis-associated E.coli
• Useful UPEC polypeptide immunogens are disclosed in references 27 and 28.
• Useful MNEC immunogens are disclosed in reference 29.
• a useful immunogen for several E.coli types is AcfD [30].
• Yersinia pestis Useful immunogens include, but are not limited to, those disclosed in references 31 and 32.
• Brucella such as B. abortus, B.canis, B.melitensis, B.neotomae, B.ovis, B.suis, B.pinnipediae.
• Francisella such as F.novicida, F.philomiragia, F.tularensis .
• Useful immunogens can be from an influenza A, B or C virus, such as the hemagglutinin, neuraminidase or matrix M2 proteins. Where the immunogen is an influenza A virus hemagglutinin it may be from any subtype e.g. HI, H2, H3, H4, H5, H6, H7, H8, H9, H10, HI 1, H12, H13, H14, H15 or H16.
• Viral immunogens include, but are not limited to, those derived from Pneumoviruses (e.g. respiratory syncytial virus, RSV), Rubulaviruses (e.g. mumps virus), Paramyxoviruses (e.g. parainfluenza virus), Metapneumoviruses and Morbilliviruses (e.g. measles).
• Pneumoviruses e.g. respiratory syncytial virus, RSV
• Rubulaviruses e.g. mumps virus
• Paramyxoviruses e.g. parainfluenza virus
• Metapneumoviruses e.g. measles
• Viral immunogens include, but are not limited to, those derived from Orthopoxvirus such as Variola vera, including but not limited to, Variola major and Variola minor.
• Viral immunogens include, but are not limited to, those derived from Picornaviruses, such as Enteroviruses, Rhinoviruses, Heparnavirus, Cardioviruses and Aphthoviruses.
• the enterovirus is a poliovirus e.g. a type 1, type 2 and/or type 3 poliovirus.
• the enterovirus is an EV71 enterovirus.
• the enterovirus is a coxsackie A or B virus.
• Bunyavirus Viral immunogens include, but are not limited to, those derived from an Orthobunyavirus, such as California encephalitis virus, a Phlebovirus, such as Rift Valley Fever virus, or a Nairovirus, such as Crimean-Congo hemorrhagic fever virus.
• an Orthobunyavirus such as California encephalitis virus, a Phlebovirus, such as Rift Valley Fever virus, or a Nairovirus, such as Crimean-Congo hemorrhagic fever virus.
• Viral immunogens include, but are not limited to, those derived from a Heparnavirus, such as hepatitis A virus (HAV).
• HAV hepatitis A virus
• Viral immunogens include, but are not limited to, those derived from a filovirus, such as an Ebola virus (including a Zaire, Ivory Coast, Reston or Sudan ebolavirus) or a Marburg virus.
• a filovirus such as an Ebola virus (including a Zaire, Ivory Coast, Reston or Sudan ebolavirus) or a Marburg virus.
• Viral immunogens include, but are not limited to, those derived from a Togavirus, such as a Rubivirus, an Alphavirus, or an Arterivirus. This includes rubella virus.
• Flavivirus Viral immunogens include, but are not limited to, those derived from a Flavivirus, such as Tick-borne encephalitis (TBE) virus, Dengue (types 1, 2, 3 or 4) virus, Yellow Fever virus, Japanese encephalitis virus, Kyasanur Forest Virus, West Nile encephalitis virus, St. Louis encephalitis virus, Russian spring-summer encephalitis virus, Powassan encephalitis virus.
• TBE Tick-borne encephalitis
• Dengue types 1, 2, 3 or 4
• Yellow Fever virus Japanese encephalitis virus
• Kyasanur Forest Virus West Nile encephalitis virus
• St. Louis encephalitis virus Russian spring-summer encephalitis virus
• Powassan encephalitis virus such as Tick
• Viral immunogens include, but are not limited to, those derived from a Pestivirus, such as Bovine viral diarrhea (BVDV), Classical swine fever (CSFV) or Border disease (BDV).
• BVDV Bovine viral diarrhea
• CSFV Classical swine fever
• BDV Border disease
• Viral immunogens include, but are not limited to, those derived from a Hepadnavirus, such as Hepatitis B virus.
• a composition can include hepatitis B virus surface antigen (HBsAg).
• a composition can include an immunogen from a hepatitis C virus, delta hepatitis virus, hepatitis E virus, or hepatitis G virus.
• Viral immunogens include, but are not limited to, those derived from a Rhabdovirus, such as a Lyssavirus ⁇ e.g. a Rabies virus) and Vesiculovirus (VSV).
• a Rhabdovirus such as a Lyssavirus ⁇ e.g. a Rabies virus
• VSV Vesiculovirus
• Viral immunogens include, but are not limited to, those derived from Calciviridae, such as Norwalk virus (Norovirus), and Norwalk-like Viruses, such as Hawaii Virus and Snow Mountain Virus.
• Viral immunogens include, but are not limited to, those derived from a SARS coronavirus, avian infectious bronchitis (IBV), Mouse hepatitis virus (MHV), and Porcine transmissible gastroenteritis virus (TGEV).
• the coronavirus immunogen may be a spike polypeptide.
• Retrovirus include, but are not limited to, those derived from an Oncovirus, a Lentivirus ⁇ e.g. HIV-1 or HIV-2) or a Spumavirus.
• Viral immunogens include, but are not limited to, those derived from an Orthoreovirus, a Rotavirus, an Orbivirus, or a Coltivirus.
• Viral immunogens include, but are not limited to, those derived from Parvovirus B19.
• Viral immunogens include, but are not limited to, those derived from a human herpesvirus, such as, by way of example only, Herpes Simplex Viruses (HSV) ⁇ e.g. HSV types 1 and 2), Varicella-zoster virus (VZV), Epstein-Barr virus (EBV), Cytomegalovirus (CMV), Human Herpesvirus 6 (HHV6), Human Herpesvirus 7 (HHV7), and Human Herpesvirus 8 (HHV8).
• HSV Herpes Simplex Viruses
• VZV Varicella-zoster virus
• EBV Epstein-Barr virus
• CMV Cytomegalovirus
• HHV6 Human Herpesvirus 6
• HHV7 Human Herpesvirus 7
• HHV8 Human Herpesvirus 8
• Papovaviruses Viral immunogens include, but are not limited to, those derived from Papillomaviruses and Polyomaviruses.
• the (human) papillomavirus may be of serotype 1, 2, 4, 5, 6, 8, 11, 13, 16, 18, 31, 33, 35, 39, 41, 42, 47, 51, 57, 58, 63 or 65 e.g. from one or more of serotypes 6, 11, 16 and/or 18.
• Viral immunogens include those derived from adenovirus serotype 36 (Ad-36).
• the immunogen elicits an immune response against a virus which infects fish, such as: infectious salmon anemia virus (ISAV), salmon pancreatic disease virus (SPDV), infectious pancreatic necrosis virus (IP V), channel catfish virus (CCV), fish lymphocystis disease virus (FLDV), infectious hematopoietic necrosis virus (IHNV), koi herpesvirus, salmon picorna-like virus (also known as picorna-like virus of atlantic salmon), landlocked salmon virus (LSV), atlantic salmon rotavirus (ASR), trout strawberry disease virus (TSD), coho salmon tumor virus (CSTV), or viral hemorrhagic septicemia virus (VHSV).
• infectious salmon anemia virus ISAV
• SPDV salmon pancreatic disease virus
• IP V infectious pancreatic necrosis virus
• CCV channel catfish virus
• FLDV fish lymphocystis disease virus
• IHNV infectious hematopoietic necrosis virus
• Fungal immunogens may be derived from Dermatophytres, including: Epidermophyton floccusum, Microsporum audouini, Microsporum canis, Microsporum distortum, Microsporum equinum, Microsporum gypsum, Microsporum nanum, Trichophyton concentricum, Trichophyton equinum, Trichophyton gallinae, Trichophyton gypseum, Trichophyton megnini, Trichophyton mentagrophytes, Trichophyton quinckeanum, Trichophyton rubrum, Trichophyton schoenleini, Trichophyton tonsurans, Trichophyton verrucosum, T. verrucosum var. album, var.
• the immunogen elicits an immune response against a parasite from the Plasmodium genus, such as P.falciparum, P.vivax, P.malariae or P. ovale.
• the invention may be used for immunising against malaria.
• the immunogen elicits an immune response against a parasite from the Caligidae family, particularly those from the Lepeophtheirus and Caligus genera e.g. sea lice such as Lepeophtheirus salmonis or Caligus rogercresseyi.
• the immunogen elicits an immune response against: pollen allergens (tree-, herb, weed-, and grass pollen allergens); insect or arachnid allergens (inhalant, saliva and venom allergens, e.g. mite allergens, cockroach and midges allergens, hymenopthera venom allergens); animal hair and dandruff allergens (from e.g. dog, cat, horse, rat, mouse, etc.); and food allergens (e.g. a gliadin).
• pollen allergens tree-, herb, weed-, and grass pollen allergens
• insect or arachnid allergens inhalant, saliva and venom allergens, e.g. mite allergens, cockroach and midges allergens, hymenopthera venom allergens
• animal hair and dandruff allergens from e.g. dog, cat, horse
• Important pollen allergens from trees, grasses and herbs are such originating from the taxonomic orders of Fagales, Oleales, Pinales and platanaceae including, but not limited to, birch (Betula), alder (Alnus), hazel (Corylus), hornbeam (Carpinus) and olive (Olea), cedar (Cryptomeria and Juniperus), plane tree (Platanus), the order of Poales including grasses of the genera Lolium, Phleum, Poa, Cynodon, Dactylis, Holcus, Phalaris, Secale, and Sorghum, the orders of Asterales and Urticales including herbs of the genera Ambrosia, Artemisia, and Parietaria.
• venom allergens including such originating from stinging or biting insects such as those from the taxonomic order of Hymenoptera including bees (Apidae), wasps (Vespidea), and ants (Formicoidae).
• the immunogen is a tumor antigen selected from: (a) cancer-testis antigens such as NY-ESO-1, SSX2, SCP1 as well as RAGE, BAGE, GAGE and MAGE family polypeptides, for example, GAGE-1, GAGE-2, MAGE-1, MAGE-2, MAGE-3, MAGE-4, MAGE-5, MAGE-6, and
• MAGE- 12 (which can be used, for example, to address melanoma, lung, head and neck, NSCLC, breast, gastrointestinal, and bladder tumors; (b) mutated antigens, for example, p53 (associated with various solid tumors, e.g., colorectal, lung, head and neck cancer), p21/Ras (associated with, e.g., melanoma, pancreatic cancer and colorectal cancer), CDK4 (associated with, e.g., melanoma),
• p53 associated with various solid tumors, e.g., colorectal, lung, head and neck cancer
• p21/Ras associated with, e.g., melanoma, pancreatic cancer and colorectal cancer
• CDK4 associated with, e.g., melanoma
• MUMl associated with, e.g., melanoma
• caspase-8 associated with, e.g., head and neck cancer
• CIA 0205 associated with, e.g., bladder cancer
• HLA-A2-R1701 associated with, e.g., beta catenin (associated with, e.g., melanoma)
• TCR associated with, e.g., T-cell non-Hodgkins lymphoma
• BCR-abl associated with, e.g., chronic myelogenous leukemia
• triosephosphate isomerase KIA 0205, CDC-27, and LDLR-
• Galectin 9 associated with, e.g., Hodgkin's disease
• proteinase 3 associated with, e.g., chronic myelogenous leukemia
• WT 1 associated with, e.g., various leukemias
• carbonic anhydrase associated with, e.g., renal cancer
• aldolase A associated with, e.g., lung cancer
• PRAME associated with, e.g., melanoma
• HER-2/neu associated with, e.g., breast, colon, lung and ovarian cancer
• mammaglobin alpha- fetoprotein
• KSA associated with, e.g., colorectal cancer
• gastrin associated with, e.g., pancreatic and gastric cancer
• telomerase catalytic protein associated with, e.g., MUC-1 (associated with, e.g., breast and ovarian cancer)
• G-250 associated with, e.g.,
• melanoma-melanocyte differentiation antigens such as MART-l/Melan A, gplOO, MC1R, melanocyte-stimulating hormone receptor, tyrosinase, tyrosinase related protein- 1/TRPl and tyrosinase related protein-2/TRP2 (associated with, e.g., melanoma);
• prostate associated antigens such as PAP, PSA, PSMA, PSH-P1, PSM-P1, PSM-P2, associated with e.g., prostate cancer;
• immunoglobulin idiotypes associated with myeloma and B cell lymphomas, for example).
• tumor immunogens include, but are not limited to, pi 5, Hom/Mel-40, H-Ras, E2A-PRL, H4-RET, IGH-IGK, MYL-RAR, Epstein Barr virus antigens, EBNA, human papillomavirus (HPV) antigens, including E6 and E7, hepatitis B and C virus antigens, human T-cell lymphotropic virus antigens, TSP-180, pl85erbB2, pl80erbB-3, c-met, mn-23Hl, TAG-72-4, CA 19-9, CA 72-4, CAM 17.1, NuMa, K-ras, pl6, TAGE, PSCA, CT7, 43-9F, 5T4, 791 Tgp72, beta-HCG, BCA225, BTAA, CA 125, CA 15-3 (CA 27.29YBCAA), CA 195, CA 242, CA-50, CAM43, CD68 ⁇ KP1, CO-029,
• Liposomes of the invention are useful as components in pharmaceutical compositions for immunising subjects against various diseases. These compositions will typically include a pharmaceutically acceptable carrier in addition to the liposomes. A thorough discussion of pharmaceutically acceptable carriers is available in reference 33.
• a pharmaceutical composition of the invention may include one or more small molecule immunopotentiators.
• the composition may include a TLR2 agonist (e.g. Pam3CSK4), a TLR4 agonist (e.g. an aminoalkyl glucosaminide phosphate, such as E6020), a TLR7 agonist (e.g. imiquimod), a TLR8 agonist (e.g. resiquimod) and/or a TLR9 agonist (e.g. IC31).
• a TLR2 agonist e.g. Pam3CSK4
• a TLR4 agonist e.g. an aminoalkyl glucosaminide phosphate, such as E6020
• TLR7 agonist e.g. imiquimod
• a TLR8 agonist e.g. resiquimod
• TLR9 agonist e.g. IC31
• compositions of the invention may include the liposomes in plain water (e.g. w.f.i.) or in a buffer e.g. a phosphate buffer, a Tris buffer, a borate buffer, a succinate buffer, a histidine buffer, or a citrate buffer. Buffer salts will typically be included in the 5-20mM range.
• compositions of the invention may have a pH between 5.0 and 9.5 e.g. between 6.0 and 8.0.
• compositions of the invention may include sodium salts (e.g. sodium chloride) to give tonicity.
• sodium salts e.g. sodium chloride
• a concentration of 10+2 mg/ml NaCl is typical e.g. about 9 mg/ml.
• compositions of the invention may include metal ion chelators. These can prolong RNA stability by removing ions which can accelerate phosphodiester hydrolysis.
• a composition may include one or more of EDTA, EGTA, BAPTA, pentetic acid, etc..
• chelators are typically present at between 10-500 ⁇ e.g. O. lmM.
• a citrate salt, such as sodium citrate, can also act as a chelator, while advantageously also providing buffering activity.
• compositions of the invention may have an osmolality of between 200 mOsm/kg and 400 mOsm/kg, e.g. between 240-360 mOsm/kg, or between 290-310 mOsm/kg.
• compositions of the invention may include one or more preservatives, such as thiomersal or 2-phenoxyethanol.
• preservatives such as thiomersal or 2-phenoxyethanol.
• Mercury-free compositions are preferred, and preservative-free vaccines can be prepared.
• compositions of the invention are preferably sterile.
• compositions of the invention are preferably non-pyrogenic e.g. containing ⁇ 1 EU (endotoxin unit, a standard measure) per dose, and preferably ⁇ 0.1 EU per dose.
• ⁇ 1 EU endotoxin unit, a standard measure
• compositions of the invention are preferably gluten free.
• compositions of the invention may be prepared in unit dose form.
• a unit dose may have a volume of between 0.1-1.0ml e.g. about 0.5ml.
• compositions may be prepared as injectables, either as solutions or suspensions.
• the composition may be prepared for pulmonary administration e.g. by an inhaler, using a fine spray.
• the composition may be prepared for nasal, aural or ocular administration e.g. as spray or drops. Injectables for intramuscular administration are typical.
• compositions comprise an immunologically effective amount of liposomes, as well as any other components, as needed.
• 'immunologically effective amount' it is meant that the administration of that amount to an individual, either in a single dose or as part of a series, is effective for treatment or prevention. This amount varies depending upon the health and physical condition of the individual to be treated, age, the taxonomic group of individual to be treated (e.g. non-human primate, primate, etc.), the capacity of the individual's immune system to synthesise antibodies, the degree of protection desired, the formulation of the vaccine, the treating doctor's assessment of the medical situation, and other relevant factors. It is expected that the amount will fall in a relatively broad range that can be determined through routine trials.
• compositions of the invention will generally be expressed in terms of the amount of RNA per dose.
• a preferred dose has ⁇ 10( ⁇ g RNA (e.g. from 10-10( ⁇ g, such as about l0 ⁇ g, 25 ⁇ g, 50 ⁇ g, 75 ⁇ g or 10( ⁇ g), but expression can be seen at much lower levels e.g. ⁇ g/dose, ⁇ 100ng/dose, ⁇ 10ng/dose, ⁇ lng/dose, etc
• the invention also provides a delivery device (e.g. syringe, nebuliser, sprayer, inhaler, dermal patch, etc.) containing a pharmaceutical composition of the invention.
• a delivery device e.g. syringe, nebuliser, sprayer, inhaler, dermal patch, etc.
• This device can be used to administer the composition to a vertebrate subject.
• Liposomes of the invention do not include ribosomes.
• liposomes and pharmaceutical compositions of the invention are for in vivo use for eliciting an immune response against an immunogen of interest.
• the invention provides a method for raising an immune response in a vertebrate comprising the step of administering an effective amount of a liposome or pharmaceutical composition of the invention.
• the immune response is preferably protective and preferably involves antibodies and/or cell- mediated immunity.
• the method may raise a booster response.
• the invention also provides a liposome or pharmaceutical composition of the invention for use in a method for raising an immune response in a vertebrate.
• the invention also provides the use of a liposome of the invention in the manufacture of a medicament for raising an immune response in a vertebrate.
• the vertebrate By raising an immune response in the vertebrate by these uses and methods, the vertebrate can be protected against various diseases and/or infections e.g. against bacterial and/or viral diseases as discussed above.
• the liposomes and compositions are immunogenic, and are more preferably vaccine compositions.
• Vaccines according to the invention may either be prophylactic (i.e. to prevent infection) or therapeutic (i.e. to treat infection), but will typically be prophylactic.
• the vertebrate is preferably a mammal, such as a human or a large veterinary mammal (e.g. horses, cattle, deer, goats, pigs).
• the human is preferably a child (e.g. a toddler or infant) or a teenager; where the vaccine is for therapeutic use, the human is preferably a teenager or an adult.
• a vaccine intended for children may also be administered to adults e.g. to assess safety, dosage, immunogenicity, etc.
• Vaccines prepared according to the invention may be used to treat both children and adults.
• a human patient may be less than 1 year old, less than 5 years old, 1-5 years old, 5-15 years old, 15-55 years old, or at least 55 years old.
• Preferred patients for receiving the vaccines are the elderly (e.g. >50 years old, >60 years old, and preferably >65 years), the young (e.g. ⁇ 5 years old), hospitalised patients, healthcare workers, armed service and military personnel, pregnant women, the chronically ill, or immunodeficient patients.
• the vaccines are not suitable solely for these groups, however, and may be used more generally in a population.
• compositions of the invention will generally be administered directly to a patient.
• Direct delivery may be accomplished by parenteral injection (e.g. subcutaneously, intraperitoneally, intravenously, intramuscularly, intradermally, or to the interstitial space of a tissue; unlike reference 1 , intraglossal injection is not typically used with the present invention).
• Alternative delivery routes include rectal, oral (e.g. tablet, spray), buccal, sublingual, vaginal, topical, transdermal or transcutaneous, intranasal, ocular, aural, pulmonary or other mucosal administration.
• Intradermal and intramuscular administration are two preferred routes. Injection may be via a needle (e.g. a hypodermic needle), but needle-free injection may alternatively be used.
• a typical intramuscular dose is 0.5 ml.
• the invention may be used to elicit systemic and/or mucosal immunity, preferably to elicit an enhanced systemic and/or mucosal immunity.
• Dosage can be by a single dose schedule or a multiple dose schedule. Multiple doses may be used in a primary immunisation schedule and/or in a booster immunisation schedule. In a multiple dose schedule the various doses may be given by the same or different routes e.g. a parenteral prime and mucosal boost, a mucosal prime and parenteral boost, etc. Multiple doses will typically be administered at least 1 week apart (e.g. about 2 weeks, about 3 weeks, about 4 weeks, about 6 weeks, about 8 weeks, about 10 weeks, about 12 weeks, about 16 weeks, etc.). In one embodiment, multiple doses may be administered approximately 6 weeks, 10 weeks and 14 weeks after birth, e.g.
• two primary doses are administered about two months apart, e.g. about 7, 8 or 9 weeks apart, followed by one or more booster doses about 6 months to 1 year after the second primary dose, e.g. about 6, 8, 10 or 12 months after the second primary dose.
• three primary doses are administered about two months apart, e.g. about 7, 8 or 9 weeks apart, followed by one or more booster doses about 6 months to 1 year after the third primary dose, e.g. about 6, 8, 10, or 12 months after the third primary dose.
• TLR3 is the Toll-like receptor 3. It is a single membrane-spanning receptor which plays a key role in the innate immune system.
• Known TLR3 agonists include poly(LC).
• TLR3 is the approved HGNC name for the gene encoding this receptor, and its unique HGNC ID is HGNC: 11849.
• the RefSeq sequence for the human TLR3 gene is GL2459625.
• TLR7 is the Toll-like receptor 7. It is a single membrane-spanning receptor which plays a key role in the innate immune system.
• Known TLR7 agonists include e.g. imiquimod.
• TLR7 is the approved HGNC name for the gene encoding this receptor, and its unique HGNC ID is HGNC: 15631.
• the RefSeq sequence for the human TLR7 gene is GI: 67944638.
• TLR8 is the Toll-like receptor 8. It is a single membrane-spanning receptor which plays a key role in the innate immune system.
• Known TLR8 agonists include e.g. resiquimod.
• TLR8 is the approved HGNC name for the gene encoding this receptor, and its unique HGNC ID is HGNC: 15632.
• the RefSeq sequence for the human TLR8 gene is GL20302165.
• RLR- 1 The RIG-I-like receptor (“RLR”) family includes various RNA helicases which play key roles in the innate immune system [41].
• RLR- 1 also known as RIG-I or retinoic acid inducible gene I
• RLR- 1 has two caspase recruitment domains near its N-terminus.
• the approved HGNC name for the gene encoding the RLR-1 helicase is "DDX58" (for DEAD (Asp-Glu- Ala-Asp) box polypeptide 58) and the unique HGNC ID is HGNC: 19102.
• the RefSeq sequence for the human RLR-1 gene is GL77732514.
• RLR-2 (also known as MDA5 or melanoma differentiation-associated gene 5) also has two caspase recruitment domains near its N-terminus.
• the approved HGNC name for the gene encoding the RLR-2 helicase is "IFIH1" (for interferon induced with helicase C domain 1) and the unique HGNC ID is HGNC: 18873.
• the RefSeq sequence for the human RLR-2 gene is GI: 27886567.
• RLR- 3 (also known as LGP2 or laboratory of genetics and physiology 2) has no caspase recruitment domains.
• the approved HGNC name for the gene encoding the RLR-3 helicase is "DHX58" (for DEXH (Asp-Glu- X-His) box polypeptide 58) and the unique HGNC ID is HGNC:29517.
• the RefSeq sequence for the human RLR-3 gene is GI: 149408121.
• PKR is a double-stranded RNA-dependent protein kinase. It plays a key role in the innate immune system.
• EIF2AK2 for eukaryotic translation initiation factor 2-alpha kinase 2
• HGNC name for the gene encoding this enzyme, and its unique HGNC ID is HGNC:9437.
• the RefSeq sequence for the human PKR gene is GL208431825.
• Figure 1 shows a gel with stained RNA. Lanes show (1) markers (2) naked replicon (3) replicon after RNase treatment (4) replicon encapsulated in liposome (5) liposome after RNase treatment (6) liposome treated with RNase then subjected to phenol/chloroform extraction.
• Figure 2 is an electron micrograph of liposomes.
• Figure 3 shows the structures of DLinDMA, DLenDMA and DODMA.
• Figure 4 shows a gel with stained RNA. Lanes show (1) markers (2) naked replicon (3) replicon encapsulated in liposome (4) liposome treated with RNase then subjected to phenol/chloroform extraction.
• Figure 6 shows protein expression at days 1, 3 and 6 after delivery of four different doses of liposome-encapsulated RNA.
• Figure 7 shows anti-F IgG titers in animals receiving virion-packaged replicon (VRP or VSRP), ⁇ g naked RNA, and ⁇ g liposome-encapsulated RNA.
• Figure 8 shows anti-F IgG titers in animals receiving VRP, ⁇ g naked RNA, and O.lg or ⁇ g liposome-encapsulated RNA.
• Figure 9 shows neutralising antibody titers in animals receiving VRP or either O.lg or ⁇ g liposome- encapsulated RNA.
• Figure 10 shows expression levels after delivery of a replicon as naked RNA (circles), liposome- encapsulated RNA (triangle & square), or as a lipoplex (inverted triangle).
• Figure 11 shows F-specific IgG titers (2 weeks after second dose) after delivery of a replicon as naked RNA (0.01-1 ⁇ g), liposome-encapsulated RNA (0.01-10 ⁇ g), or packaged as a virion (VRP, 10 6 infectious units or IU).
• Figure 12 shows F-specific IgG titers (circles) and PRNT titers (squares) after delivery of a replicon as naked RNA ( ⁇ g), liposome-encapsulated RNA (0.1 or ⁇ g), or packaged as a virion (VRP, 10 6 IU). Titers in naive mice are also shown. Solid lines show geometric means.
• Figure 13 shows intracellular cytokine production after restimulation with synthetic peptides representing the major epitopes in the F protein, 4 weeks after a second dose.
• the y-axis shows the % cytokine+ of CD8+CD4-.
• Figure 14 shows F-specific IgG titers (mean logio titers + std dev) over 63 days ( Figure 14A) and 210 days ( Figure 14B) after immunisation of calves.
• the three lines are easily distinguished at day 63 and are, from bottom to top: PBS negative control; liposome-delivered RNA; and the "Triangle 4" product.
• Figure 15 shows SEAP expression (relative intensity) at day 6 against pKa of lipids used in the liposomes. Circles show levels for liposomes with DSPC, and squares for liposomes without DSPC; sometimes a square and circle overlap, leaving only the square visible for a given pKa.
• Figure 16 shows anti-F titers expression (relative to RVOl, 100%) two weeks after a first dose of replicon encoding F protein.
• the titers are plotted against pKa in the same way as in Figure 15.
• the star shows RV02, which used a cationic lipid having a higher pKa than the other lipids.
• Triangles show data for liposomes lacking DSPC; circles are for liposomes which included DSPC.
• Figure 17 shows total IgG titers after replicon delivery in liposomes using, from left to right, RVOl, RV16, RV17, RV18 or RV19. Bars show means. The upper bar in each case is 2wp2 (i.e. 2 weeks after second dose), whereas the lower bar is 2wpl .
• Figure 18 shows IgG titers in 13 groups of mice. Each circle is an individual mouse, and solid lines show geometric means. The dotted horizontal line is the assay's detection limit.
• the 13 groups are, from left to right, A to M as described below.
• Figure 19 shows (A) IL-6 and (B) IFNa (pg/ml) released by pDC.
• the black bar is wild-type mice, grey is rsql mutant.
• replicons are used below. In general these are based on a hybrid alphavirus genome with non-structural proteins from Venezuelan equine encephalitis virus (VEEV), a packaging signal from Sindbis virus, and a 3' UTR from Sindbis virus or a VEEV mutant.
• VEEV Venezuelan equine encephalitis virus
• the replicon is about lOkb long and has a poly-A tail.
• Plasmid DNA encoding alphavirus replicons (named: pT7-mVEEV-FL.RSVF or A317; pT7- mVEEV-SEAP or A306; pSP6-VCR-GFP or A50) served as a template for synthesis of RNA in vitro.
• the replicons contain the alphavirus genetic elements required for RNA replication but lack those encoding gene products necessary for particle assembly; the structural proteins are instead replaced by a protein of interest (either a reporter, such as SEAP or GFP, or an immunogen, such as full-length RSV F protein) and so the replicons are incapable of inducing the generation of infectious particles.
• a bacteriophage (T7 or SP6) promoter upstream of the alphavirus cDNA facilitates the synthesis of the replicon RNA in vitro and a hepatitis delta virus (HDV) ribozyme immediately downstream of the poly(A)-tail generates the correct 3 '-end through its self-cleaving activity.
• HDV hepatitis delta virus
• run-off transcripts were synthesized in vitro using T7 or SP6 bacteriophage derived DNA-dependent RNA polymerase. Transcriptions were performed for 2 hours at 37°C in the presence of 7.5 mM (T7 RNA polymerase) or 5 mM (SP6 RNA polymerase) of each of the nucleoside triphosphates (ATP, CTP, GTP and UTP) following the instructions provided by the manufacturer (Ambion). Following transcription the template DNA was digested with TURBO DNase (Ambion).
• RNA was precipitated with LiCl and reconstituted in nuclease-free water.
• Uncapped RNA was capped post-transcriptionally with Vaccinia Capping Enzyme (VCE) using the ScriptCap m7G Capping System (Epicentre Biotechnologies) as outlined in the user manual; replicons capped in this way are given the "v" prefix e.g. vA317 is the A317 replicon capped by VCE.
• Post-transcriptionally capped RNA was precipitated with LiCl and reconstituted in nuclease-free water. The concentration of the RNA samples was determined by measuring OD 2 60nm- Integrity of the in vitro transcripts was confirmed by denaturing agarose gel electrophoresis.
• RNA was encapsulated in liposomes made by the method of references 1 1 and 42.
• the liposomes were made of 10% DSPC (zwitterionic), 40% DLinDMA (cationic), 48% cholesterol and 2% PEG- conjugated DMG (2kDa PEG). These proportions refer to the %> moles in the total liposome.
• DLinDMA (l ,2-dilinoleyloxy-N,N-dimethyl-3-aminopropane) was synthesized using the procedure of reference 6.
• DSPC (l ,2-Diastearoyl-sn-glycero-3-phosphocholine) was purchased from Genzyme. Cholesterol was obtained from Sigma- Aldrich.
• PEG-conjugated DMG (1 ,2-dimyristoyl-sn-glycero- 3-phosphoethanolamine-N-[methoxy(polyethylene glycol), ammonium salt), DOTAP (1 ,2-dioleoyl- 3-trimethylammonium-propane, chloride salt) and DC-chol (3 -[N-(N',N'-dimethylaminoethane)- carbamoyl] cholesterol hydrochloride) were from Avanti Polar Lipids.
• lipids were dissolved in ethanol (2ml), a RNA replicon was dissolved in buffer (2ml, lOOmM sodium citrate, pH 6) and these were mixed with 2ml of buffer followed by 1 hour of equilibration. The mixture was diluted with 6ml buffer then filtered. The resulting product contained liposomes, with -95%) encapsulation efficiency.
• fresh lipid stock solutions were prepared in ethanol.
• 37 mg of DLinDMA, 1 1.8 mg of DSPC, 27.8 mg of cholesterol and 8.07 mg of PEG-DMG were weighed and dissolved in 7.55 mL of ethanol.
• the freshly prepared lipid stock solution was gently rocked at 37°C for about 15 min to form a homogenous mixture.
• 755 iL of the stock was added to 1.245 mL ethanol to make a working lipid stock solution of 2 mL. This amount of lipids was used to form liposomes with 250 ⁇ g RNA.
• RNA working solution was also prepared from a stock solution of ⁇ g ⁇ L in 100 niM citrate buffer (pH 6). Three 20 mL glass vials (with stir bars) were rinsed with RNase Away solution (Molecular BioProducts) and washed with plenty of MilliQ water before use to decontaminate the vials of RNases. One of the vials was used for the RNA working solution and the others for collecting the lipid and RNA mixes (as described later). The working lipid and RNA solutions were heated at 37°C for 10 min before being loaded into 3cc luer-lok syringes. 2 mL citrate buffer (pH 6) was loaded in another 3 cc syringe.
• RNA and the lipids were connected to a T mixer (PEEKTM 500 ⁇ ID junction, Idex Health Science) using FEP tubing (fluorinated ethylene-propylene; all FEP tubing used has a 2mm internal diameter and a 3mm outer diameter).
• the outlet from the T mixer was also FEP tubing.
• the third syringe containing the citrate buffer was connected to a separate piece of FEP tubing. All syringes were then driven at a flow rate of 7 mL/min using a syringe pump. The tube outlets were positioned to collect the mixtures in a 20 mL glass vial (while stirring).
• the stir bar was taken out and the ethanol/aqueous solution was allowed to equilibrate to room temperature for 1 h. 4 ml of the mixture was loaded into a 5 cc syringe, which was connected to a piece of FEP tubing and in another 5 cc syringe connected to an equal length of FEP tubing, an equal amount of 100 mM citrate buffer (pH 6) was loaded. The two syringes were driven at 7mL/min flow rate using the syringe pump and the final mixture collected in a 20 mL glass vial (while stirring).
• the mixture collected from the second mixing step were passed through a Mustang Q membrane (an anion-exchange support that binds and removes anionic molecules, obtained from Pall Corporation).
• a Mustang Q membrane an anion-exchange support that binds and removes anionic molecules, obtained from Pall Corporation.
• 4 mL of 1 M NaOH, 4 mL of 1 M NaCl and 10 mL of 100 mM citrate buffer (pH 6) were successively passed through it. Liposomes were warmed for 10 min at 37°C before passing through the membrane.
• liposomes were concentrated to 2 mL and dialyzed against 10-15 volumes of IX PBS using by tangential flow filtration before recovering the final product.
• TFF system and hollow fiber filtration membranes were purchased from Spectrum Labs (Rancho Dominguez) and were used according to the manufacturer's guidelines. Polysulfone hollow fiber filtration membranes with a 100 kD pore size cutoff and 8 cm 2 surface area were used. For in vitro and in vivo experiments formulations were diluted to the required RNA concentration with IX PBS.
• Figure 2 shows an example electron micrograph of liposomes prepared by these methods. These liposomes contain encapsulated RNA encoding full-length RSV F antigen. Dynamic light scattering of one batch showed an average diameter of 141nm (by intensity) or 78nm (by number).
• RNA and RNA concentration were determined by Quant-iT RiboGreen RNA reagent kit (Invitrogen), following manufacturer's instructions.
• the ribosomal RNA standard provided in the kit was used to generate a standard curve.
• Liposomes were diluted lOx or lOOx in IX TE buffer (from kit) before addition of the dye. Separately, liposomes were diluted lOx or lOOx in IX TE buffer containing 0.5% Triton X before addition of the dye (to disrupt the liposomes and thus to assay total RNA).
• RNA from liposomes was shown to protect RNA from RNase digestion. Experiments used 3.8mAU of RNase A per microgram of RNA, incubated for 30 minutes at room temperature. RNase was inactivated with Proteinase K at 55°C for 10 minutes. A 1 : 1 v/v mixture of sample to 25:24: 1 v/v/v, phenol: chloroform: isoamyl alcohol was then added to extract the RNA from the lipids into the aqueous phase. Samples were mixed by vortexing for a few seconds and then placed on a centrifuge for 15 minutes at 12k RPM. The aqueous phase (containing the RNA) was removed and used to analyze the RNA.
• RNA a reporter enzyme SEAP; secreted alkaline phosphatase
• SEAP secreted alkaline phosphatase
• Expression levels were measured in sera diluted 1 :4 in IX Phospha-Light dilution buffer using a chemiluminescent alkaline phosphate substrate. 8-10 week old BALB/c mice (5/group) were injected intramuscularly on day 0, 50 ⁇ 1 per leg with O. ⁇ g or ⁇ g RNA dose. The same vector was also administered without the liposomes (in RNase free IX PBS) at ⁇ g. Virion-packaged replicons were also tested.
• Virion-packaged replicons used herein were obtained by the methods of reference 43, where the alphavirus replicon is derived from the mutant VEEV or a chimera derived from the genome of VEEV engineered to contain the 3' UTR of Sindbis virus and a Sindbis virus packaging signal (PS), packaged by co-electroporating them into BHK cells with defective helper RNAs encoding the Sindbis virus capsid and glycoprotein genes.
• PS Sindbis virus packaging signal
• encapsulation increased SEAP levels by about 1 ⁇ 2 log at the ⁇ g dose, and at day 6 expression from a O. ⁇ g encapsulated dose matched levels seen with ⁇ g unencapsulated dose.
• the replicon was administered in encapsulated form (with two different purification protocols, O. ⁇ g RNA), or mixed with the liposomes after their formation (a non-encapsulated "lipoplex", O. ⁇ g RNA), or as naked RNA ( ⁇ g).
• Figure 10 shows that the lipoplex gave the lowest levels of expression, showing that shows encapsulation is essential for potent expression.
• mice received various combinations of (i) self-replicating RNA replicon encoding full-length RSV F protein (ii) self- replicating GFP-encoding RNA replicon (iii) GFP-encoding RNA replicon with a knockout in nsP4 which eliminates self-replication (iv) full-length RSV F-protein. 13 groups in total received:
• Results in Figure 18 show that F-specific IgG responses required encapsulation in the liposome rather than mere co-delivery (compare groups C & D).
• a comparison of groups K, L and M shows that the RNA provided an adjuvant effect against co-delivered protein, and this effect was seen with both replicating and non-replicating RNA.
• a replicon was constructed to express full-length F protein from respiratory syncytial virus (RSV). This was delivered naked ( ⁇ g), encapsulated in liposomes (0.1 or ⁇ g), or packaged in virions (10 6 IU; "VRP") at days 0 and 21.
• Figure 7 shows anti-F IgG titers 2 weeks after the second dose, and the liposomes clearly enhance immunogenicity.
• Figure 8 shows titers 2 weeks later, by which point there was no statistical difference between the encapsulated RNA at O. ⁇ g, the encapsulated RNA at ⁇ g, or the VRP group.
• Neutralisation titers (measured as 60% plaque reduction, "PRNT60") were not significantly different in these three groups 2 weeks after the second dose (Figure 9).
• Figure 12 shows both IgG and PRNT titers 4 weeks after the second dose.
• Figure 13 confirms that the RNA elicits a robust CD8 T cell response.
• VRP liposome Titer ratios (VRP liposome) at various times after the second dose were as follows:
• liposome-encapsulated RNA induces essentially the same magnitude of immune response as seen with virion delivery.
• FIG. 11 shows IgG titers in mice receiving the replicon in naked form at 3 different doses, in liposomes at 4 different doses, or as VRP (10 6 IU).
• the response seen with ⁇ g liposome-encapsulated RNA was statistically insignificant (ANOVA) when compared to VRP, but the higher response seen with 10 ⁇ g liposome- encapsulated RNA was statistically significant (p ⁇ 0.05) when compared to both of these groups.
• Bone marrow derived dendritic cells were obtained from wild-type mice or the "Resq" (rsql) mutant strain.
• the mutant strain has a point mutation at the amino terminus of its TLR7 receptor which abolishes TLR7 signalling without affecting ligand binding [44].
• the cells were stimulated with replicon RNA formulated with DOTAP, lipofectamine 2000 or inside a liposome.
• IL-6 and INFa were induced in WT cells but this response was almost completely abrogated in mutant mice.
• the pKa of a lipid is measured in water at standard temperature and pressure using the following technique:
• 0.3mM solution of fluorescent probe toluene nitrosulphonic acid (TNS) in ethanokmethanol 9: 1 is prepared by first making 3mM solution of TNS in methanol and then diluting to 0.3mM with ethanol.
• An aqueous buffer containing sodium phosphate, sodium citrate sodium acetate and sodium chloride, at the concentrations 20mM, 25mM, 20mM and 150 mM, respectively, is prepared.
• the buffer is split into eight parts and the pH adjusted either with 12N HC1 or 6N NaOH to 4.44-4.52, 5.27, 6.15-6.21, 6.57, 7.10-7.20, 7.72-7.80, 8.27-8.33 and 10.47-11.12.
• 400nL of 2mM lipid solution and 800 ⁇ of 0.3mM TNS solution are mixed.
• probe/lipid mix • 1.5 iL of probe/lipid mix are added to 242.5 iL of buffer in a lmL 96 well plate. This is done with all eight buffers. After mixing, ⁇ of each probe/lipid/buffer mixture is transferred to a 250nL black with clear bottom 96 well plate ⁇ e.g. model COSTAR 3904, Corning). A convenient way of performing this mixing is to use the Tecan Genesis RSP150 high throughput liquid handler and Gemini Software.
• Fluorescence of each probe/lipid/buffer mixture is measured (e.g. with a SpectraMax M5 spectrophotometer and SoftMax pro 5.2 software) with 322nm excitation, 431nm emission (auto cutoff at 420nm).
• This method gives a pKa of 5.8 for DLinDMA.
• the pKa values measured by this method for cationic lipids of reference 5 are included below.
• the cationic lipids of reference 5 are used. These lipids can be synthesised as disclosed in reference 5.
• the liposomes formed above using DlinDMA are referred to hereafter as the "RV01" series.
• the DlinDMA was replaced with various cationic lipids in series “RV02" to “RV12” as described below.
• Two different types of each liposome were formed, using 2% PEG2000-DMG with either (01) 40% of the cationic lipid, 10% DSPC, and 48% cholesterol, or (02) 60% of the cationic lipid and 38% cholesterol.
• (01) and (02) liposomes shows the effect of the neutral zwitterionic lipid.
• RV02 liposomes were made using the following cationic lipid (pKa >9, without a tertiary amine):
• RV03 liposomes were made using the following cationic lipid (pKa 6.4):
• RV05 liposomes were made using the following cationic lipid (pKa 5.85):
• RV08 liposomes were made using the following cationic lipid (pKa 5.72):
• RVl 1 liposomes were made using the following cationic lipid (pKa 6.41):
• RV17 liposomes were made using the following cationic lipid (pKa 6.1) [45]:
• RV18 liposomes were made using DODMA.
• RV19 liposomes were made using DOTMA, and RV13 liposomes were made with DOTAP, both having a quaternary amine headgroup. These liposomes were characterised and were tested with the SEAP reporter described above.
• the following table shows the size of the liposomes (Z average and polydispersity index), the % of RNA encapsulation in each liposome, together with the SEAP activity detected at days 1 and 6 after injection. SEAP activity is relative to "RV01(02)" liposomes made from DlinDMA, cholesterol and PEG-DMG:
• RV09 (01) 6.07 165.3 (0.169) 72.2 65.1 453.9 RV09 (02) 6.07 179.5 (0.157) 65 68.5 658.2
• Figure 15 plots the SEAP levels at day 6 against the pKa of the cationic lipids. The best results are seen where the lipid has a pKa between 5.6 and 6.8, and ideally between 5.6 and 6.3.
• liposomes were also used to deliver a replicon encoding full-length RSV F protein.
• Total IgG titers against F protein two weeks after the first dose (2wpl) are plotted against pKa in Figure 16. The best results are seen where the pKa is where the cationic lipid has a pKa between 5.7-5.9, but pKa alone is not enough to guarantee a high titer e.g. the lipid must still support liposome formation.
• vA317 self-replicating replicon encoding RSV F protein.
• BALB/c mice, 4 or 8 animals per group were given bilateral intramuscular vaccinations (50 iL per leg) on days 0 and 21 with the replicon ( ⁇ g) alone or formulated as liposomes with the RV01 or RV05 lipids (see above; pKa of 5.8 or 5.85) or with RV13.
• the RV01 liposomes had 40% DlinDMA, 10% DSPC, 48% cholesterol and 2% PEG-DMG, but with differing amounts of RNA.
• the RV05(01) liposomes had 40% cationic lipid, 48% cholesterol, 10% DSPC, and 2% PEG-DMG; the RV05(02) liposomes had 60% cationic lipid, 38% cholesterol, and 2% PEG-DMG.
• the RV13 liposomes had 40% DOTAP, 10% DPE, 48% cholesterol and 2% PEG-DMG.
• naked plasmid DNA (20 ⁇ g) expressing the same RSV-F antigen was delivered either using electroporation or with RV01(10) liposomes (O. ⁇ g DNA). Four mice were used as a naive control group.
• Liposomes were prepared by method (A) or method (B).
• method (A) fresh lipid stock solutions in ethanol were prepared. 37 mg of cationic lipid, 11.8 mg of DSPC, 27.8 mg of cholesterol and 8.07 mg of PEG-DMG were weighed and dissolved in 7.55 mL of ethanol. The freshly prepared lipid stock solution was gently rocked at 37°C for about 15 min to form a homogenous mixture. Then, 226.7 iL of the stock was added to 1.773 mL ethanol to make a working lipid stock solution of 2 mL.
• RNA or, for RV01(10), DNA was also prepared from a stock solution of ⁇ in 100 mM citrate buffer (pH 6). Three 20 mL glass vials (with stir bars) were rinsed with RNase Away solution (Molecular BioProducts) and washed with plenty of MilliQ water before use to decontaminate the vials of RNases.
• RNA working solution was used for the RNA working solution and the others for collecting the lipid and RNA mixes (as described later).
• the working lipid and RNA solutions were heated at 37°C for 10 min before being loaded into 3cc syringes.
• 2 mL of citrate buffer (pH 6) was loaded in another 3 cc syringe.
• Syringes containing RNA and the lipids were connected to a T mixer (PEEKTM 500 ⁇ ID junction) using FEP tubing.
• the outlet from the T mixer was also FEP tubing.
• the third syringe containing the citrate buffer was connected to a separate piece of FEP tubing.
• the two syringes were driven at 7mL/min flow rate using a syringe pump and the final mixture collected in a 20 mL glass vial (while stirring).
• liposomes were concentrated to 2 mL and dialyzed against 10-15 volumes of IX PBS using TFF before recovering the final product.
• TFF system and hollow fiber filtration membranes were purchased from Spectrum Labs and were used according to the manufacturer's guidelines.
• Polyethersulfone (PES) hollow fiber filtration membranes (part number P-Cl-lOOE-100-OlN) with a 100 kD pore size cutoff and 20 cm 2 surface area were used.
• PES Polyethersulfone
• formulations were diluted to the required RNA concentration with IX PBS.
• Preparation method (B) differed in two ways from method (A). Firstly, after collection in the 20 mL glass vial but before TFF concentration, the mixture was passed through a Mustang Q membrane (an anion-exchange support that binds and removes anionic molecules, obtained from Pall Corporation, Ann Arbor, MI, USA). This membrane was first washed with 4 mL of 1 M NaOH, 4 mL of 1 M NaCl and 10 mL of 100 mM citrate buffer (pH 6) in turn, and liposomes were warmed for 10 min at 37°C before beign filtered. Secondly, the hollow fiber filtration membrane was Polysulfone (part number P/N: X1AB-100-20P).
• the Z average particle diameter, polydispersity index and encapsulation efficiency of the liposomes were as follows:
• the nucleic acid was DNA not RNA
• F-specific serum IgG titers were as follows:
• T cells which are cytokine-positive and specific for RSV F51-66 peptide are as follows, showing only figures which are statistically significantly above zero:
• liposome formulations significantly enhanced immunogenicity relative to the naked RNA controls, as determined by increased F-specific IgG titers and T cell frequencies.
• RVOl and RV05 RNA vaccines were more immunogenic than the RV13 (DOTAP) vaccine. These formulations had comparable physical characteristics and were formulated with the same self- replicating RNA, but they contain different cationic lipids.
• RVOl and RV05 both have a tertiary amine in the headgroup with a pKa of about 5.8, and also include unsaturated alkyl tails.
• RV13 has unsaturated alkyl tails but its headgroup has a quaternary amine and is very strongly cationic.
• the cationic lipid in RVOl liposomes was replaced by RV16, RV17, RV18 or RV19.
• Total IgG titers are shown in Figure 17. The lowest results are seen with RV19 i.e. the DOTMA quaternary amine.
• Liposomes with different lipids were incubated with BHK cells overnight and assessed for protein expression potency. From a baseline with RV05 lipid expression could be increased 18x by adding 10% l,2-diphytanoyl-sn-glycero-3-phosphoethanolamine (DPyPE) to the liposome, lOx by adding 10% 18:2 (cis) phosphatidylcholine, and 900x by instead using RVOl .
• DPyPE diphytanoyl-sn-glycero-3-phosphoethanolamine
• vA142 encodes the full-length wild type surface fusion (F) glycoprotein of RSV but with the fusion peptide deleted, and the 3' end is formed by ribozyme-mediated cleavage. It was tested in three different mouse strains.
• mice were given bilateral intramuscular vaccinations (50 per leg) on days 0 and 22. Animals were divided into 8 test groups (5 animals per group) and a naive control (2 animals):
• Group 1 were given naked replicon (1 ⁇ g).
• Group 2 were given ⁇ g replicon delivered in liposomes "RVOl (37)" with 40%) DlinDMA, 10%> DSPC, 48% Choi, 2% PEG-conjugated DMG.
• Group 3 were given the same as group 2, but at O. ⁇ g RNA.
• Group 4 were given ⁇ g replicon in "RV17(10)" liposomes (40% RV17 (see above), 10% DSPC, 49.5% cholesterol, 0.5% PEG-DMG).
• Group 5 were ⁇ g replicon in "RV05(11)" liposomes (40% RV07 lipid, 30% 18:2 PE (DLoPE, 28% cholesterol, 2% PEG-DMG).
• Group 7 were given 5 ⁇ g RSV-F subunit protein adjuvanted with aluminium hydroxide.
• Group 8 were a naive control (2 animals)
• F-specific serum IgG GMTs were:
• F-specific IgGl and IgG2a titers were as follows:
• RSV serum neutralizing antibody titers at days 35 and 49 were as follows (data are 60% plaque reduction neutralization titers of pools of 2-5 mice, 1 pool per group):
• VRPs lxl 0 6 IU
• F-specific IgG titers were: Day 1 2 3 4 5 6 7 8 9
• F-specific IgGl and IgG2a titers were as follows:
• RSV serum neutralizing antibody titers at days 35 and 49 were as follows (data are 60% plaque reduction neutralization titers of pools of 2-5 mice, 1 pool per group):
• F-specific IgG titers were:
• F-specific IgGl and IgG2a titers were as follows: IgG 1 2 3 4 5 6 7 8
• RSV serum neutralizing antibody titers at days 35 and 49 were as follows:
• RV01 liposomes with DLinDMA as the cationic lipid were used to deliver RNA replicons encoding cytomegalovirus (CMV) glycoproteins.
• CMV cytomegalovirus
• the "vA160" replicon encodes full-length glycoproteins H and L (gH/gL), whereas the "vA322" replicon encodes a soluble form (gHsol/gL).
• the two proteins are under the control of separate subgenomic promoters in a single replicon; co-administration of two separate vectors, one encoding gH and one encoding gL, did not give good results.
• mice 10 per group, were given bilateral intramuscular vaccinations (50 iL per leg) on days 0, 21 and 42 with VRPs expressing gH/gL (lxl 0 6 IU), VRPs expressing gHsol/gL (lxl 0 6 IU) and PBS as the controls.
• Two test groups received ⁇ g of the vA160 or vA322 replicon formulated in liposomes (40% DlinDMA, 10% DSPC, 48% Choi, 2% PEG-DMG; made using method (A) as discussed above, but with 150 ⁇ g RNA batch size).
• the vA160 liposomes had a Zav diameter of 168nm, a pdl of 0.144, and 87.4% encapsulation.
• the vA322 liposomes had a Zav diameter of 162nm, a pdl of 0.131 , and 90% encapsulation.
• the replicons were able to express two proteins from a single vector.
• CMV neutralization titers (the reciprocal of the serum dilution producing a 50% reduction in number of positive virus foci per well, relative to controls) were as follows: RNA expressing either a full-length or a soluble form of the CMV gH/gL complex thus elicited high titers of neutralizing antibodies, as assayed on epithelial cells. The average titers elicited by the liposome-encapsulated RNAs were at least as high as for the corresponding VRPs.

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