Development of a Live Varicella Vaccine (Oka Strain)

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1 Development of a Live Varicella Vaccine (Oka Strain) Michiaki Takahashi M.D. Emeritus Professor, Osaka University 26 th January, 2009 Prince Mahidol Awardees on Public Health Lecture Annual National Epidemiology Seminar

2 Severe Case Rash 8000 Moderate Case Rash Mild Case Rash 50

3 Electron micrograph of VERO cells infected with VZV. (a) Intranuclear particles of VZV. Two capsids with round, electron-dense cores (arrow mark) and several capsids with fragmentary cores of low electron density. 88,000. (b) Extracellular particles of VZV. Two enveloped particles with capsids and cores (arrow mark) and several aberrant forms with envelopes and various electrondense materials. 100,000. (Provided by Dr. S. Nii.) Takahashi M. Adv. In Virus Research 1983

4 Electron micrograph of purified VZ virion negatively stained with phosphotungstate. Bar = 100 nm. Takahashi M. Adv. In Virus Research 1983

5 Problems on Development of Live Varicella Vaccine 1. Possible oncogenicity of Herpes group virus. E.B., Herpes simplex 2. Probable occurence of zoster after administration of live varicella vaccine. 3. Cell-associated nature of VZV Obtaining Cell-free VZV is difficult. 4. VZV is extreamely heat-labile, therefore handling of VZV need particular caution.

6 Passage History of Oka Varicella Vaccine Virus Isolation of Varicella Virus (Oka strain) from vesicular fluid of varicella patient using primary human embryonic lung cells Passage in human embryonic lung cells (HEL) at times Passage in guinea pig embryo fibroblast (GPEF) at times Passage in human diploid cells (WI-38)* at 37 2 nd passage (Master seed lot virus) 3 rd passage Passage in human diploid cells (MRC-5)** 2 nd passage (Seed lot virus) 4 th passage (batch 7900) ( 8200) ( 8300) : WI-38 cells obtained from Hayflick L. (Stanford U. USA) : MRC-5 cells obtained from Jacobs P. (National Institute for Medical Research, London, UK)

7 Candidate live Varicella Vaccine (Oka strain) 1. Temperature sensitivity Infectivity at 39<37 Lower at 39 than parental virus and wild viruses 2. Host-dependency Better replication in guinea pig embryo fibroblasts than that shown by parental virus or wild VZV with low passage in human embryonic fibroblasts

8 Adsorption of various strains of VZV to GPEL, GPES, and GPEK cells assessed by the infectious center assay Virus Input virus dose (PFU) No. (PFU) of infectious centers (%) with: GPEL GPES GPEK Oka (vaccine) (52.8) (36.5) (1.8) Oka (HEL, 5 th passage) (4.0) (5.1) (0.2) Kawaguchi (HEL, 10 th passage) (7.9) (12.2) (0.5) Inoue (HEL, 5 th passage) (5.1) (4.2) (0.1) GPEL: Guinea Pig Embryo Lung, GPES: Guinea Pig Embryo Skin, GPEK: Guinea Pig Embryo Kidney At 4 hours inoculation, cells were trypsinized, and as infectious center assay was performed on HuEF cells.

9 Growth of VZV of various strains in cultured GPEL cells No. of infectious center (PFU/plate) Hours after inoculation Oka vaccine strain Oka (HEL, 5 th passage) Kawaguchi (HEL, 10 th passage)

10 Oka vaccine virus showed less efficient virusspreading activity than its parental virus. fold increase Oka parent Oka vaccine S7-01 S days after infection

11 Vaccination for Healthy Children at Home Antibody Responses in Healthy Children at Home Given Various Doses of Varicella Vaccine Subcutaneously Passage level Vaccine dose* (P.F.U.) Seroconversion Mean C.F. antibody titre GPE 6 500* 200* 100* 19/20** 11/12 7/ GPE12 WI-38, /9 11/11 10/ ** Number in which seroconversion occurred/number vaccinated. Takahashi M. Asano Y. et al. Lancet ; , 1974

12 CLINICAL AND SEROLOGICAL RESPONSES IN CHILDREN IN HOSPITAL GIVEN A LIVE VARICELLA VACCINE IMMEDIATELY AFTER A CASE OF VARICELLA OCCURRED Underlying disease Purpura Myelitis Hepatitis Enteritis Arthritis Nephritis Asthma Enteritis Hepatitis P.M. P.M. Hæmangioma V.S.D. Hepatitis Nephrosis Nephrosis Nephritis Nephritis Nephritis Nephritis Nephritis Enteritis Nephritis Steroid therapy C.F. antibody titres 0 wk. 1 wk. 2 wk. 4 wk. 10 wk Onset (day) P.M. = purulent meningitis. Fever Maximum temperature () Live Vaccine used to prevent the spread of varicella in children in hospital Takahashi M. Otsuka T. Okuno Y, Asano Y. Yazaki T. Isomura S. Lancet Nov. 30, , 1974 Duration (days) Rash V.S.D. = ventricular septal defect.

13 Clinical Symptoms in Unvaccinated and Vaccinated Children Less Than 2 Years Old at First Outbreak of Varicella Grade of Clinical Symptoms No. of Cases Rash No. of Cases * With Maximum Temperature () Convulsion Zoster >40 Unvaccinated Severe 16 Confluent (6.3) 0 7 (2.8) 7 (4.0) 2 (4.0) 0 0 Moderate 15 Countable (4.5) 3 (1.3) 7 (2.4) 5 (4.2) Mild 12 Several (3.9) 1 (1.0) (8 mo later) Vaccinated Mild 8 Several (4.5) 1 (1.0) No symptoms Numbers in parentheses indicate mean duration of r ash in days. * Numbers in parentheses indicate mean duration of temperature greater than 37.5 C in days. Baba K. Yabuuchi H. Okuni H. Takahashi M. Pediatrics 61: , 1978

14 Viral isolation from mononuclear cells and antibody responses after close contact with patients with varicella. Day of testing after onset of varicella Viral isolation from mononuclear cells 0/3 (0) 0/4 (0) 0/1 (0) 1/2 (50) 1/3 (33) ND 4/4 (100) 4/5 (80) 4/17 (24) 7/32 (22) 0/14 (0) 0/3 (0) 0/1 (0) 0/3 (0) Detectable antibodies* ND ND 0/1 (0) ND 0/2 (0) 0/1 (0) 0/4 (0) 0/5 (0) 0/13 (0) 0/28 (0) 0/12 (0) 4/12 (33) 9/18 (50) 14/14 (100) NOTE. Data are no. of subjects/no. tested (%). ND = not done. *Measured by the assay for fluorescent antibody to membrane antigen. Asano Y. et al. J. Infect. Dis. 152(5); , 1985

15 Isolation of VZV from children inoculated with live virus vaccine (strain Oka). Day of testing after vaccination Viral isolation from Mononuclear cells Throat Detectable antibodies* Positive skin reaction 0 ND 3 0/11 (0) 4-5 0/14 (0) 6-7 0/17 (0) 8-9 0/6 (0) /11 (0) ND 0/3 (0) 0/28 (0) 0/8 (0) 0/8 (0) 0/13 (0) 0/11 (0) 0/16 (0) 2/8 (25) 0/6 (0) 2/5 (40) ND 8/8 (100) ND 28/28 (100) 0/22 (0) 0/10 (0) 1/11 (9) 8/11 (73) 4/5 (80) 6/7 (86) 17/20 (85) NOTE. Data are no. of vaccinees/no. tested (%). ND = not done. *Measured by the assay for fluorescent antibody to membrane antigen. Asano Y. et al. J. Infect. Dis. 152(5); , 1985

16 Efficacy of Varicella Vaccine Breakthrough case : 20 ( 6080 mild case)

17 Mutations between the Oka vaccine and its parental viruses TRL 1 nt A R3 R1 20k 40k R2 C UL B 60k Ori R I E 4 100k IRL IRS 120 US k TRS R4 Ori R5 L 125k(bp) silent mutations causing aa conversion deletions or insertions in noncoding region H 80k gb (ORF 31) gh (ORF 37) gi (ORF 67) % of total protein Glycoprotein in the VZV skin antigen KDa ge (ORF 68) gc (ORF 14) gk (ORF 5) % of total protein 1.20 KDa gl (ORF 60) % of total protein KDa 20

18 Amino acid mutations between Oka parent and Vaccine viruses gene Oka parent Oka vaccine gene 6 A (Ser) G (Pro) gene 9A T (Trp) T/C(Trp/Arg) gene 10 T (Ala) T/C(Ala/Val) gene 21 C (Thr) C/T(Thr/Ile) gene 31 A (Ile) A/G(Ile/Val) gene 39 T (Met) T/C(Met/Thr) gene 50 T (Ser) T/C(Ser/Gly) gene 52 A (Ile) A/G(Ile/Val) gene 55 gene 59 gene 62 gene 64 G (Ala) T (Cys) A (Leu) A (Leu) T (Ile) A (Val) A (Arg) T (Ser) A (Val) A (Leu) A (Met) A (Gln) G/A(Ala/Thr) T/C(Cys/Arg) A/G(Leu/Pro) A/G(Leu/Ser) C (Val) G (Ala) C (Gly) C (Gly) A/G(Val/Ala) A/G(Leu/Pro) A/G(Met/Thr) A/G(Gln/Arg) function helicase/primase complex unknown α -TIF latent associated protein gb unknown HSV-1 gm homolog helicase/primase complex helicase/primase complex uracil-dna glycosylase IE62, transactivator unknown (Gomi Y. et al. J. Virol. 2002)

19 ORF 62 (Open Reading Frame 62) IE gene 62 (Immediately Early Gene 62) transactivator: serve to initiate transcription of viral gene essential for VZV replication

20 Infection of conjunctivae and/or mucosa of upper respiratory tract DAY 0 Viral replication in regional lymph nodes Primary viremia Viral replication in liver, Spleen and (?) other organs Secondary viremia DAY 4-6 INCUBATION PERIOD Infection of skin and appearance of vesicular rash DAY 14 A probable scheme of pathogenesis of chickenpox (From Grose, 1981; re- Printed from Pediatrics, copyright American Academy of Pediatrics, 1981).

21 Pathogenesis of Zoster Primary infection Varicella Latent virus Neuron in dorsal root ganglion Virus transit up peripheral nerve Spinal cord Age Zoster X-irradiation (act via depressed CMI) Recurrence Activation of virus in neuron Virus transit down peripheral nerve Spinal cord (Adapted from Mims and White, 1984)

22 It maybe that appearance of vesicular rash is closely correlated with viremia. Vesicular rash may be correlated with latency of VZV in ganglia. Usually no rash appear in normal children after vaccination. Therefore it may be hoped that incidence of zoster would be less in vaccinated normal children than those who acquired natural varicella.

23 Intradermal Skin Test (Delayed-type Hypersensitive Immune Reaction) Antigen Presenting cell Antigen IL-1 Growth and Differentiation Antigen Presentation Tc TH0 TH2 TH1 Tc Production of cytokine MIF MAF LIF IL-2 IL-4 IL-5 IL-6 IL-10 LT Mediating cell Macrophage TNF PGE2 IL-1 Neutrophil leucocyte Lysosomal enzyme B cell activation Appearance of delayed-type allergy Cell infiltration Elevation of vascular permeability Exsudation of plasma Edema Erythema Tissue damage Killing of targeted cell IL-1 MIF MAF LIF : Interleukin 1 : Macrophage Immigration Inhibitory factor : Mcrophage Immigration Activating Factor : Leucocyte Immigration Inhibitory Factor PGE2 : Prostaglandin E2 LT : Lymphotoxin TNF : Tumor Necrosis Factor IL-2 : Interleukin 2

24 Flowchart of preparing Varicella Skin Test Antigen Cultivation with TCM-199 medium without serum Harvest of Infectious cells and fluid after shaking culture bottles Heat treatment (56, 30min) Concentration with Ultrafilter membrane Ultra Centrifugation at 20,000rpm 2hr. 4C Filtration 0.22µm Purified VZV Skin antigen suspension

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26 Result of VZV skin test in 12 patients with ophthalmic zoster (27-85 years, mean age 57 years) and control subjects (18 to 58 years, mean age 52 years) 3+ Degree of erythema Control Time after onset of zoster eruption (weeks) Tanaka Y. et al. Amer. J. of Ophthal. 98: 7-10, 1984

27 Change of VZV Skin Test Reaction in 9 Zoster Cases who were Negative in the Initial Skin Test and then Received Later Skin Test VZV Skin Test Reaction(mm) Days after appearance of Rash Torinuki W, Clinical Dermatology (in Japanese) 6; , 1991

28 Enhancement of immunity against VZV by giving live varicella vaccine to the elderly assessed by VZV skin test and IAHA, gpelisa antibody assay Subjects: s years old Vaccine: Commercial lyophilized Attenuated Live Varicella Vaccine (BIKEN) Potency of vaccine: 30,000 plaque forming unit (PFU)/dose Takahashi M. et al. VACCINE 21(2003)

29 VZV skin test reaction (5059 years of age) (mm in diameter) Post immunization with live varicella vaccine Preimmunization

30 VZV skin test reaction (6069 years of age) (mm in diameter) Post immunization with live varicella vaccine Preimmunization

31 VZV skin test reaction (7079 years of age) (mm in diameter) Post immunization with live varicella vaccine Preimmunization

32 Conversion Rate in Skin Test Reaction After giving Varicella Vaccine (Biken) in the Age Groups years old () 15/ years old () 11/ years old () 11/ ( ) ( ) ( ) ( ) 0~4 mm in long diameter 5~9 mm in long diameter 10~14 mm in long diameter 15~ mm in long diameter Viral potency: 30,000 plaque forming unit (PFU/dose) Takahashi M. et al. VACCINE 21: , 2003