Advantages of Peptide Vaccines

Transcription

1 Advantages of Peptide Vaccines Chemical purity/safety Ease of production/low cost Precisely defined and targeted T & B cell epitopes Target cryptic epitopes Circumvent enhancing antibody sites Avoid T cell tolerance Stability Mutability 1

2 Advantages to the Use of rvlps as Vaccine Platforms Carriers for hapten and carbohydrate B cell epitopes Immunogenicity/inherent adjuvant activity Self-assembly/multimeric Safe/non-infectious High yield/low costs Therapeutic vaccinations/circumvent self tolerance (Mab therapy alternative) Chemical conjugate vaccines Encapsidate molecular adjuvants (TLR ligands) 2

3 Licensed rvlp Vaccines HBV, rhbsag (env) HPV, L1 capsid 3

4 HBcAg Structure Immunodominant Loop N nm Cryo-EM of HBcAg (7.4Å) Polypeptide fold of monomer, α-helices shown. 21kDa 240 polypeptides per particle. 4

5 Licensed Hybrid-VLP Vaccines None Problems: 1) Pre-existing HBcAg Immunity: Antibody / T cell Tolerance 2) Assembly/Stability (<50% success for all hybrid-vlps) 5

6 Strategy to Address Pre-existing Immunity Problem: Selection of a Species Variant Core Particle Hepadnavirus Family Genus: Orthohepadnavirus Primates: human, non-human Rodents: woodchuck, ground squirrel, arctic squirrel Genus: Avihepadnavirus Duck Heron Goose Characteristics: hepatotropic partially dsdna RT of RNA intermediate 6

7 Rodent Cores Are More Immunogenic than HBc STRAIN (H-2) Anti-CORE TITER (1/dilution) 0 5,000 25, , ,000 3 x x x 10 6 IMMUNOGEN B10.BR (k) B10.D1 (q) B10.D2 (d) B10.M (f) B10.PL (u) B10.RIII (r) B10.S (s) B10 (b) Billaud, JN, et al. (2005) J Virol, vol 79, p WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc WHc HBc GSc ASc 7

8 HBc and WHc Do Not Cross-React at the Ab Level Antigen Anti-WHc Anti-HBc Anti-GSc Anti-ASc Immunogen WHc HBc GSc ASc 5,000 25, , ,000 3 x x x 10 6 Titer (1/dilution) Billaud, JN, et al. (2005) J Virol, vol 79, p

9 Effect of Pre-existing Antibody to HBcAg Carrier Anti-HBc Anti-[DP 4 NPN] º 2º-10d 2º-24d 3º-2W 3º-6W 0 1º 2º-10d 2º-24d 3º-2W 3º-6W CFA HBc-CS 1 HBc-CS 1 CFA HBc-CS 1 HBc-CS 1 HBc HBc HBc-PS 1 P16 HBc-PS 1 P16 9 Schoedel, F, et al. (1994) J Exp Med, vol 180, p 1037

10 Deletion of VLP Carrier B cell Epitopes Lowers Carrier Antigenicity 1.5x10(7) Antibody Titer (1/dilution) 3x10(6) 625, ,000 25,000 5,000 WHcAg FLw(Δ1)-CS-78 FLw(Δ2)-CS-78 na α-whc α-nanp 10

11 Deletion of Carrier B cell Epitopes Improves Insert Immunogenicity Antibody Titer (1/dilution) 1.5x10(7) 3x10(6) 625, ,000 25,000 5,000 1,000 FLw(Δ2)-CS-78 FLw(Δ1)-CS º 2º Time (weeks) 11

12 Low Level Cross-Reactivity Between WHc and HBc at CD4 T cell Level Strain H-2 Immunogen CD4 + Epitope Map B10.BR (k) WHc HBc B10.D1 (q) WHc HBc B10.D2 (d) WHc HBc B10.M (f) WHc HBc weak intermediate strong 12

13 Use of WHc Circumvents T cell Tolerance to the HBc HBcAg(Mal) WHcAg(Mal) 625, ,000 Anti-Mal (1/dilution) 125,000 25,000 Week ,000 25,000 Week /+ HBe-Tg +/+ HBe-Tg Billaud, JN, et al. (2007) Vaccine, vol 25, p

14 Endemic Regions of Malaria & HBV Malaria HBV Presence of Malaria Malaria No Malaria HBV Carrier Rates High (>8% HBsAg) Intermediate (2-7% HBsAg) Low (<2 HBsAg)

15 Strategy to Address Hybrid VLP Assembly Problem Diversity of Insertion Sites on WHcAg /- 28 C-terminal modifications insertion sites - COOH NH2 44 Diversity of C-termini on WHcAg adapted from Billaud, JN, et al. (2005) J Virol, vol 79, p

16 Combinatorial Technology Epitope Optimal Assembly Platform C-terminus Insert Position Mal fal. C-long 78 Mal vivax HyW 78 Cetp HyW 74 FV-1 HyW2 75 FV-2 150C 74 HIV-2 HyW2 75 HIV-3 HyW2 75 HIV-4 150C 75 FluA M2 WT-R 74 FluA M2(-) HyW 78 HCV-E2 #17 HCV-E2 #24 HyW2 HyW adapted from Billaud, JN, et al. (2005) J Virol, vol 79, p

17 Basic Inserts (pi >7) Adversely Affect Assembly of Hybrid VLPs Epitope Sequence pi AZ2 FRHDSGY OMP-2 EDANGTRDHKKGRHT HIV4.1 RIKQIGMPGGK IgE GETYQSRVTHPHLPRALMRSTTK HV1 GEIKNCSFNISTSIRGKVQKEYAFF HV3 PKVSFEPIPIHYCAPAGFAILKCNN SEB KKKVTAQELD HV2 LTSCNTSVITQACPKVSFEPIPIHYC HV4 THGIRPVVSTQLLLNGSLAEEE MV DRAAGQPAGDRADGQPAG CE FGFPEHLLVDFLQSL AZ1 DAEFRHDSGYEV M2(-) SLLTEVETPIRNEWGARANDSSD HC10 [Proprietary] Mal NANPNVDPNANPNANPNANP MB DPPPPNPNDPPPPNPN VLP Assembly adapted from Billaud, JN, et al. (2005) J Virol, vol 79, p

18 WHcAg Platform Acidification of the Insert Rescues Assembly Epitope Sequence pi VLP Assembly AZ2 FRHDSGY EEFRHDSGYEE OMP-2 EDANGTRDHKKGRHT EEEDANGTRDHKKGRHTEE HIV4.1 RIKQIGMPGGK EERIKQIGMPGGKEE HBcAg Platform AZ2 FRHDSGY EEFRHDSGYEE OMP-2 EDANGTRDHKKGRHT EEEDANGTRDHKKGRHTEE HIV4.1 RIKQIGMPGGK EERIKQIGMPGGKEE GScAg Platform AZ2 FRHDSGY EEFRHDSGYEE HIV4.1 RIKQIGMPGGK EERIKQIGMPGGKEE adapted from Billaud, JN, et al. (2005) J Virol, vol 79, p 13656

19 Rapid Screening Technology Construct: #1 #2 #3 #4 Ab dilution a e i a e i a e i a e i monoclonal antibodies a = assembly e = expression level i = insert antigenicity Proprietary ELISA-based method Applied to bacterial lysate, avoiding labor-intensive purification step Assesses: expression; assembly; insert antigenicity Facilitates rapid turn-around, i.e., epitope conception to purified VLP in 2-4 weeks 19

20 Combinatorial Tools for WHcAg 17 insertion sites Insertion Sites 28 C-terminal Modifications Acidification of the loop Rapid Screening Technology = >95% Assembly Success ssrna-binding 1 N 44 TLR-7/8 Ligand 187C 28 C-terminal modifications Billaud JN, et al., J Virol (2005) vol 79, p Billaud JN, et al., Vaccine (2007) vol 25, p

21 HBc/WHc Are Preferentially Presented by B cell APC in vitro and in vivo B10/+/+ B10/B KO IL-2 IFN-γ IL-2 IFN-γ HBc HBe p adapted from Lee, BO, et al. (2009) J Immunol, vol 182, p 6670 Ag (μg/ml)

22 HBc Is Preferentially Presented by B1 APC adapted from Lee, BO, et al. (2009) J Immunol, vol 182, p

23 B cell Uptake of HBc Elicits Upregulation of B7.2 Costimulatory Message 23 Milich, DR et al. (1997) PNAS, vol 94, p 14648

24 Non-B cell APCs Can Process and Present Immune-Complexed HBc 300 IL IFN-γ Monoclonal Anti-HBc : APC : B cell Non-B cell B cell Non-B cell Lee, BO, et al. (2009) J Immunol, vol 182, p

25 Full Length HBc (ssrna+) Possesses Enhanced Immunogenicity Mediated Through TLR-7 Activation +/+ TLR-7 KO HBcAg 183 /+/+ HBcAg 183 /TLR-7 KO HBcAg 149 /+/+ HBcAg 149 /TLR-7 KO Lee, BO, et al. (2009) J Immunol, vol 182, p 6670 Time (weeks) Anti-HBc isotypes 25

26 ssrna Encapsidation Improves B Cell Response to NANP Insert 3x10(6) Antibody Titer (1/dilution) 625, ,000 25,000 5,000 1, CS-78 (no RNA) FLw-CS-78 (encapsidated RNA) α-whc α-nanp 26

27 ssrna Acts Through TLR7 IgG Titers for Mice Immunized with FLw-CS-78 (w/ ssrna) 3x10(6) Antibody Titer (1/dilution) 625, ,000 25,000 5,000 1,000 TLR7 KO mice Wildtype mice α-whc α-nanp 27

28 Encapsidation of TLR7 Ligand Alters IgG Isotype Distribution Anti-NANP Titer (1/dilution) 3x10(6) 625, ,000 25,000 5,000 1, CS-78 (no RNA) FLw-CS-78 (encapsidated RNA) IgG1 IgG2a IgG2b IgG3 28

29 HBc-Specific CD4 Cells Are Regulated by TLR-7 Activation IL-2 IFN-γ WT TLR7KO WHcAg (μg/ml) WHcAg (μg/ml) 29 Lee, BO, et al. (2009) J Immunol, vol 182, p 6670

30 Advantages of Integral Molecular Adjuvants Immune stimulant is delivered directly to the APC Co-ligation of B cell receptor and TLR Avoids the potential toxicity of systemic administration The ligand is protected from nucleases or proteases 30

31 A Variety of Hybrid WHc-CS VLPs Have Been Produced HYBRID PARTICLE 188-M74 150C-M74 150R-M74 C-Long(M3)-M74 HyW-M74 150C-M75 150C-M77 150C-M78 C-Long-M78 HyW-M78 Anti-INSERT 1 o 2 o TIME 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o 1 o 2 o IMMUNOGENICITY Anti-WHc HyW-(NH2)-M 1 o 2 o HyW-(COOH)-M 1 o 2 o Billaud, JN, et al. (2007) Vaccine, vol 25, p

32 WHc-Malaria VLP Vaccine Candidates P. falciparum B cell epitopes CS Repeat (1 to 2) CS Non-Repeat (1 to 5) ssrna TLR-7/8 Ligand N 48 P. falciparum CS T cell epitopes (1 to 3) UTC TH.3R CS.3T 32

33 Passive Transfer of Anti-WHc-CS VLP Antibodies Prevents Hybrid-Sporozoite Liver Infection 100K Parasite 18S rrna Copies 10K dilution: 1/10 1/10 1/50 1/250 1/1250 Control Sera anti-cs Sera 33

34 Active Immunization with WHc-CS VLP Prevents Hybrid Sporozoite Liver Infection WHc-CS in vivo Immunization Hybrid P. falciparum/p. berghei Sporozoite in vivo Challenge/Protection anti-nanp Titer (1/dilution) º 2º WHc-CS Immunized WHcAg Control Immunized Time (wk) Parasite 18S rrna Copies 10,000 1, WHc-CS WHcAg Control Immunogen naive Control 34

35 Fine Specificity of T cells Primed by HBc-CS Antigens (in vitro) HBcAg (NANP) 5 CS C B10.PL B10.RIII B10.S B10.D B10.BR B10 B10.D Minimum [Ag] to recall IFNγ (μg/ml) Milich, DR et al. (2002) Vaccine, vol 20, p 771

36 A Core VLP Can Confer Insert Specific CD4 + Protection ) BALB/c mice were immunized with a chimeric HBc-based VLP in CFA, containing a mouse malaria CD4 + T cell site. 1) Animals were challenged with 50,000 sporozoites and infection of the liver determined. Parasite RNA (pg) Naïve Controls HBc HBc-PyCS (CD4 + epitope) 36

37 Induction of Malaria-Specific CD8+ T cells by Immunization with HBc-CD8 + Site VLPs No. of CD8 + T cells/1m cells No. of CD8 + T cells/1m cells Priming: CD8 + -HBc (50μg SC) rvac-cd8 + (3e7, ip) CD8 + -HBc (50μg SC) none Priming: CD8 + -HBc (50μg, sc) Sporozt (1e5, iv) none none Booster: rvac-cd8 + (3e7, ip) CD8 + -HBc (50μg SC) CD8 + -HBcrVac-CD8 + (50μg SC) (3e7, ip) Booster: Sporozt (1e5, iv) CD8 + -HBc (50μg, sc) Sporozt (1e5, iv) CD8 + -HBc (50μg, sc) 37

38 Rationale for the Use of WHc/HBcAg vs HBsAg as a VLP Carrier 15M 3M 625K 2,500 HBsAg WHcAg (GSK RTS,S) 38 B10 B10.D2 B10.S B10.BR B10.M C3H.Q Antibody Titer (1/dilution)

39 Antibody Titers for RTS,S and Apovia ICC-1132 in Rhesus Macaques α-nanp Titer (1/dilution) Weeks 1 RTS,S Apovia ICC-1132 adapted from Langermans, JA, et al. (2005) Vaccine, vol 23, p 4935 & Steward, VA (2006) Vaccine, vol 24, p

40 Comparison of WHc vs HBc VLP Anti-NANP (1/dilution) WHc-CS HBc-CS (Apovia ICC-1132) Time (wks) 52 40

41 RTS,S WHc-CS Apovia (ICC-1132) Malaria B epitopes CS Repeats: (NANP) 16 only CS Repeats CS Non-Repeats CS Repeats T epitopes CS, C-terminus CS (UTC) CS CS (TH.3R) CS (CS.T3) Carrier HBsAg (human pathogen) T cell dependent WHcAg (full-length) (non-human pathogen) T cell dependent or independent HBcAg (truncated) (human pathogen) T cell dependent or independent fold less immunogenic in mice fold more immunogenic in mice fold more immunogenic in mice Soluble HBsAg less immunogenic in humans N.D. Soluble HBcAg more immunogenic in humans MHC nonresponder genotypes (mice & human) No MHC nonresponders identified No MHC nonresponders identified Pre-existing anti-hbs from HBV infection No Pre-existing anti-hbs from HBV infection Pre-existing anti-hbs from HBV infection Immune tolerance in HBV chronics No immune tolerance in HBV chronics Immune tolerance in HBV chronics N.D. Delete carrier B cell sites N.D. Requires co-expression of HBsAg for HBsAg-CS assembly Self assembly of WHc-CS Self assembly of HBc-CS Cannot express in bacteria Bacterial expression Bacterial expression N.D. 100% protection vs 10k Tg sporozoites N.D. 41

42 RTS,S WHc-CS Apovia (ICC-1132) Endogenous Molecular Adjuvants None ssrna TLR Ligands None Stability to Fixation Lyophilization Lyophilization? Cold Chain Not Required Not Required Required Formulation/ Adjuvants Absolute requirement for immunostimulatory adjuvant (AS02A, MPL/QS21/oil) to be determined Montanide 720, Alum Phase II Clinical Results 1-3 dose, 0 protection 3 dose +AS02A, 30-50% N.D. N.D. 1 dose, 0 protection N.D. 42

43 Evolution of the Hepadnaviral Core-Based Malaria VLP Vaccine VRISD/ VLP Biotech WHcAg Carrier to Resolve Pre-existing Immunity Assembly WHc-CS (+ TLR ligand) 20/10ug (2x) mice: 10 7 anti-cs Titer 100% protection vs Tg sporozoites TSRI ICC Apovia HBc-CS VLPs P. berghei P. yoleii 100% protection in vivo Anti-CS Titer HBc-CS P. falciparum (ICC-1132) mice 20/10ug (2x) 10 6 ICC-1132 R. macaques 2x10 5 ICC-1132 cynamolgus 1x /20ug (2x) Phase I ICC ug (3x)/Alum 0.5x10 3 ICC ug (1x)/ISA x10 3 Phase II ICC ug (1x)/ISA x protection 43

44 Influence of Adjuvant on Hybrid WHc VLP Immunogenicity ADJUVANT IFA SALINE AL-OH (100%) AL-OH (5%) AL-PO4- (100%) AL-PO4- (0%) CpG Non-CpG MPL-Aq MPL-SE (Syn) MPL-RAS TIME (wks) ISA-720 (30:70) 4 6 ISA-720 (70:30) 4 6 CFA 4 6 Milich, DR et al. (2002) Vaccine, vol 20, p Anti-NANP RESPONSE (% of IFA)

45 Chemical Conjugation vs. Recombinant Insertion Chemical Conjugation Recombinant Insertion Fu, T-M, et al. (2009) Vaccine, vol 27, p

46 Summary (1) WHcAg-VLP is a potent and flexible vaccine carrier Inexpensive production in bacteria Fully recombinant technology (not limited to conjugation) Display of 240 epitopes per VLP Compatible with lyophilization Derived from a non-human pathogen WHcAg combinatorial tools enable efficient assembly of chimeric VLPs with most inserts 46

47 Summary (2) The WHcAg-VLP can encapsidate TLR ligands Avoids potential toxicity from systemic delivery of adjuvant Direct delivery of immune stimulant to specific APC Co-ligation of BCR and TLR Ligand protected from nucleases and proteases Deletion of carrier B cell epitopes Higher anti-insert immunogenicity/protection Improves use for multiple vaccines HBc/WHc-CS VLPs demonstrated protection against: P. falciparum P. yoelii P. berghei 47

48 VRISD Immunology: Molecular Biology: VCU Protein Chemistry: JHSPH Malaria: Collaborators Dave Milich Byung Lee Joyce Jones Cory Peters David Whitacre Bryan Darsow Darrell Peterson Fidel Zavala 48