Journal of Vaccines Research & Vaccination Category: Medical Type: Research Article

Preclinical Phase of the Inactivated Zika Vaccine Development in Thailand

Nitatpattana N1*, Duangkhae P2, Rodpai E1, Akkhawattanangkul Y3, Nakgoi K4, Poolam K2, Treekarunasawat J2, Juntarapornchai S1, Palabodeewat S1, Padungchai P1, Wanlayaporn D1, Chaiyo K2, Wiriyarat W3, Pesirikan N2 and Gonzalez JP5,6

1 Institute Of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
2 Government Pharmaceutical Organization, Ministry Of Public Health, Bangkok, Thailand
3 Faculty Of Veternary Science Mahidol University, Nakhon Pathom, Thailand
4 Surat Thani Provincial Livestock Office Department Of Livestock Development, Surat Thani Province, Thailand
5 Georgetown University, School Of Medicine, Washington D.C., United States
6 ERP International LLC, Laurel, Maryland, United States

*Corresponding Author(s):
Nitatpattana N
Institute Of Molecular Biosciences, Mahidol University, Nakhon Pathom, Thailand
Tel:+66 (0) 2441 9337,
Fax:+66 (0) 2441 9336
Email:narong.nit@mahidol.ac.th

Received Date: Apr 07, 2022
Accepted Date: Apr 14, 2022
Published Date: Apr 21, 2022

Abstract

Purpose: The Zika virus (ZIKV), a member of Flaviviridae family, is associated with serious congenital and neuropathological abnormalities in Thailand and abroad. Although several vaccines are being prepared by different agencies, there are no approved vaccines against ZIKV infection in human.

Methods: In this context, the need for vaccine development, our study was based on the development of the preclinical phase of an Inactivated Zika Vaccine using the Asian strain SV0010-15. Inactivated Zika vaccine was produced using WHO Vero cells (RCB 10-87) growth with formalin inactivated Serum Free Medium (VP-SFM) and following WHO recommendation and Quality controls. Pre-clinical models were developed using small animal for immune response, safety and dose formulation followed using no-human primate animal model for vaccine efficacy.

Results: Our results showed that an optimal and suitable dose formulation of Zika vaccine/Alum adjuvant (5 µg/250 µg) was obtained when performed with a use of two doses injections. Also, it showed to be safe, immunogenic and to have a protective effect against two ZIKV genotypes in Non-Human Primate. Ultimately, the first step of the development of this vaccine candidate has been successfully done accordingly to WHO guidelines and shown that the product could be developed in GMP pilot scale for a clinical stage at the request of health authorities.

Keywords

Inactivated vaccine ; Thailand ; vaccine ; Zika vaccine ; Zika virus

Introduction

The Zika virus (ZIKV) is a mosquito-borne virus from the family Flaviviridae and genus Flavivirus which includes, among others, several human pathogenic flaviviruses such as Japanese encephalitis virus (JEV), Dengue virus (DENV). ZIKV is an arbovirus transmitted principally by Aedes mosquito species including Aedes aegypti and Aedes albopictus. The geographical distribution of these mosquito species across tropical and subtropical regions has led to several outbreaks, including the recent pandemic in Brazil, followed by the Pacific islands and other areas of North and South America [1]. Today, ZIKV is globally widespread [2]. ZIKV was first identified and isolated from a sentinel monkey in a Ugandan forest in 1947 [3] and emerged as a global health threat in December 2015 [4]. For the past seven decades, ZIKV has had limited impact on public health systems worldwide, while few human cases were reported in Southeast Asia and Africa. It was not until 2007 that ZIKV caused large outbreaks and was first detected outside Asia and Africa. Furthermore, ZIKV emerged as a threat in Oceania with a large outbreak in French Polynesia in 2013-2014. Since 2015 ZIKV became endemic in Brazil, with increased pathogenicity impacting the nervous system with severe congenital malformations (microcephaly) as well as neurological as Guillain-Barré syndrome (GBS) with acute inflammatory demyelinating neuropathy [5-7]. On February 1st, 2016, WHO declared the ZIKV epidemic in Brazil a public health emergency of international concern.  In Thailand the first report of the possible presence of Zika virus was recorded in 1963 [8]. In early 2013, ZIKV was also detected among travelers and more recently several autochthonous cases were observed providing evidence that ZIKV is widespread throughout Thailand [9-10]. In 2018, United Kingdom health authorities (Public Health England (PHE) have classified Thailand as having a risk of Zika virus transmission).

Several ZIKV vaccine candidates have now been developed and tested in preclinical and clinical trials. These include nucleic acid vaccines (DNA and RNA vaccines), inactivated whole virus vaccines, live attenuated vaccines, viral vectored vaccines, protein antigen vaccines in the form of purified proteins from expression systems, or virus-like particles [11].  In mid-2016, WHO, UNICEF and a working group of independent subject matter experts have proposed a ZIKV vaccine target product profile (TPP) for use in an emergency (i.e., urgent need during pregnancy in endemic areas), or in a future emerging outbreak scenario. The TPP suggested non-replicating platforms such as inactivated whole virion and subunit based and those that use alum as adjuvant. The proposed model of TPP was the inactivated Zika vaccine elicited ZIKV envelope specific neutralizing antibodies and protected non-human primates (NHP) against challenge with the virus strains from Brazil and Puerto Rico [12]. In September 2017, the Center for Vaccine Development (CVD) Institute of Molecular Biosciences Mahidol University, Government Pharmaceutical Organization (GPO) and National Vaccine Institute (NVI) Ministry of Public Health took the challenge and decided to develop an Inactivated Zika vaccine in Thailand. In September 2017, the three parties signed a Memorandum of Understand (MOU) to develop such Inactivated Zika vaccine by using WHO Vero cell as recommended by the TPP. The present study report on the development of the pre-clinical phase of this ZIKV vaccine in Thailand.

Materials And Methods

Cell

WHO Vero cells RCB 10-87 were derived from GMP cell bank product that was prepared and extensively characterized at Government Pharmaceutical Organization (GPO).

Zika virus strains

The infectious strain of ZIKV SV0010/15 was used to produce the inactivated vaccine candidate (GenBank: KX051562.1). ZIKV SV0010/15 was generously provided by the Epidemiology Department of Disease Control, Ministry of Public Health, Thailand. ZIKV SV0010/15 was amplified in WHO Vero cell using Hyper-flask (Corning, Corning, NY) and harvested on day 4 and 6 after inoculation. The virus titer tested 7 log10 plaque forming unit/ml and confirmed free of mycoplasma. The identity of Zika virus was confirmed by genomic RNA sequencing from Direct PCR amplicon. ZIKV strain MR766 (African strain) was used for the heterologous ZIKV challenge in primate model. Inactivation of ZIKV candidate vaccine strain SV0010/15 was produced inside the virus vaccine clean room facility at Center for Vaccine Development, Institute of Molecular Biosciences, Mahidol University. WHO Vero cell was scale up in Hyper-flask (Corning;). ZIKV inoculation in Vero cells was performed using serum free medium (VP-SFM, Gibco) and carried out at a standardized MOI of 0.01 PFU/cell. The virus was harvested at 4 and 6 days. Pooled virus harvest was clarified by Refrigerated Centrifugation 5,000 rpm about 10 minute and filter 0.45 micron using Sartopure 0.45 µ PP3 (Sartorius), concentrated by tangential flow filtration (TFF) Pellicon 2 Mini Filter Ultrafiltration 500 Kda (Merck millipore). Residual Vero cellular DNA was removed by using nuclease digestion (Benzonase endonuclease, Merck), and the viral suspension purified on Capto Core 700 (GE Healthcare Life Sciences, Pittsburg, USA) column. ZIKV was inactivated with 0.05% of formalin for 7 days at 22 °C following the previously described method [13]. Formalin was removed by diafiltration 100 Kda (Merck millipore). Ultimately, the antigen concentration was adjusted with a 6% sucrose, PBS pH 7.4 buffer. Inactivation was considered as complete when no infectious particle could be detected by Indirect Fluorescent after three serial amplifications of the sample in vitro in C6/36 for 7 days. Quality controls were applied accordingly to the Requirements for Japanese Encephalitis Vaccine (Inactivated) for Human Use as previously described [14].

Preclinical Immunogenicity in Small mammal

The preclinical phase on the immune response was carried out in Balb/c mice at the animal facility in Faculty of Veterinary Science, Mahidol University. Balb/c female mice 6–8 weeks of age were purchased from M-CLEA Bioresource Company, Thailand. The animals (n = 6 specimen by group) were allocated randomly to different groups. Mice were vaccinated with booster doses (day 0 and day 14) of 5μg vaccines and 10μg adjuvant (2% Alhydrogel, Invivogen) by IM routes in a 100μl volume. All of mice blood samples were collected on day 35 after the second dose, by cardiac puncture [15].

Preclinical Immunogenicity in Primates

Two groups of nine (9) 4–5 years old cynomolgus macaque (Macaca fascicularis), from the animal facility of the National Primate Center, Chulalongkorn University at Saraburi Province Thailand, were vaccinated including: A first group (n=6) that received a booster dose (day 0, 14) of 5 μg of inactivated Zika vaccine and adjuvant (2% Alhydrogel, Invivogen); A second group (n=3) serves as negative control. All specimen received only adjuvant and PBS7.4 and were randomly injected by IM routes in a 100 μl volume vaccine. Also, blood samples were collected on day 0, 7, 14, 21, 30, 60 after the first injection.

Ethics

All animal experiment protocols for small mammal models were approved by the Faculty of Veterinary Science, Mahidol University-Institute Animal Care and Use Committee (COA. No: MUVS-2017-12-56). The animal experiment protocol for the Pre-clinical Immunogenicity in Primates was approved by the Chulalongkorn University Animal Care and Use Committee (COA. No: 2075002).

Challenge test in Monkeys

On day 180, the first group of cynomolgus macaque was separated in two subgroups: The subgroup I (1/1 to 1/3) challenged by the ZIKV strain SV0010/15 (Asian strain, titer 5.7 log10) and subgroup II (1/4 to 1/6) challenged by ZIKV strain MR766 (African strain, titer 5.7 log10). Both of them will be injected about 0.5 ml by sub cutaneous (sc) route. 

The second group was positive control challenged (group III) (2/1 to 2/3). It was challenge by ZIKV strain SV0010/15 with the same dose (0.5 ml of 5.7 log10 titer). Blood samples were collected on a daily base from day 180 to day 187 following a previously establish protocol [12].

ELISA (IgG) serology test

Briefly, we used the FBS-depleted ZIKV antigen strain MR766 which derived from Vero cells as previously described, has been slightly adapted from the described technique using Flavivirus mouse brain antigen and replaced by the use of Zika virus cell culture antigen [16].

ELISA (IgM) serology test

ZIKV specific capture IgM were by a modified ELISA as previously described [17-18].

ELISA optical reading value

For each sample the ratio (P/N) in optical density reading (OD) value was positive control serum including sample well value divided by the OD value of the negative control serum well. It was used for both IgG and IgM ELISA tests. Thus, The sample was considered positive when the P/N value ≥ 2 or sample OD higher than the negative control OD about 2 times [18].

Plaque Reduction Neutralization Test (PRNT50)

Briefly, we used the ZIKV strain SV0010/15 (Asian strain) and MR 766 (African strain) for neutralizing homologous and heterologous antibody respectively following the protocol as previously described [19].

RT-PCR

Following [20] we used the outer primer pairs of Uni for (5′ 1171 TGGGGNAAYSRNTGYGGNYTNTTYGG 1197 3′) and Unirev (5′ 2178 CCNCCHRNNGANCCRAARTCCCA 2155 3′) and, followed by the inner pairs of Mounifor2 (5′ 1209 GGRDRMDTBKWSAYVTGYGCNAWRTT 1235 3′) and Mounirev2 (5′ 2094 CCNATNSWRCTHCCHKHYYTRWRCCA 2068 3′). Amplification was performed using the following procedure: 1 cycle at 50°C for 30 min and 95°C for 2 min, and 35 cycles at 95°C for 20s, 55°C for 20s, and 68°C for 30s.

Virus Isolation

C6/36 cells were used for virus isolation and identification by Indirect Fluorescent (IFA) as previously described [21].

Plaque assay

Vero cells monolayer was used for virus titration by plaque assay. The plaques were counted, and the viral titer was calculated and expressed as PFU/ml [19].

Results

Group (1)

Vaccine/Alum (Formulation)

Geometric Mean Titer (GMT) (2)

 

 

Day 0

Day 35

A

5/100

<10(3)/<10(4)

205/131

B

5/250

<10/<10

638/923

Table 1 Immunogenicity of Inactivated Zika vaccine strain SV0010/15 in Balb/C mice by Plaque Reduction Neutralization Test 50 % (PRNT50) 

Legend: (1) = Mice group;

                     (2) = Geometric Mean Titer (GMT) was mean calculated from six mice neutralizing antibody;

              (3) = Neutralized by Zika virus strain SV0010/15 (homologous strain);   

                   (4)  = Neutralized by Zika virus strain MR766 (heterologous strain)

Inactivated Zika vaccine strain SV0010/15 demonstrated to be safe and immunogenic in Balb/c mice. Also, the dose formulation of Zika vaccine/alum at (5 µg /250 µg) produced a variable immunogenicity for ZIKV genotypes (Table 1).

From the Six cynomolgus macaques immunized with two doses of Zika vaccine/alum no local or systemic reactions were observed after injection. Most of the monkeys showed high positive ELISA of both IgM and IgG on day 14 (Figure 1).

Time (day post inoculation)

 

Immunized group (1)

Monkey

Negative control group (2)

 

1/1

1/2

1/3

1/4

1/5

1/6

2/1

2/2

2/3

IgM

IgG

IgM

IgG

IgM

IgG

IgM

IgG

IgM

IgG

IgM

IgG

IgM

IgG

IgG

IgG

IgG

IgG

0

0(3)

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

7

0

0

2.3

0

2.4

0

0

0

3.4

0

2.7

0

0

0

0

0

0

0

14

2.5

2.5

11.6

3.7

18.3

5.1

5.0

4.8

30

3.4

22.2

3.1

0

0

0

0

0

0

30

0

2.2

5.8

3.1

9.7

5.0

2.6

5.3

18.1

3.3

16.8

3.9

0

0

0

0

0

0

Figure 1: ELISA Reacting antibody from immunized cynomolgus macaque with inactivated Zika vaccine strain ZIKV SV0010/15 

Time (day post inoculation)

Monkey

Immunized group (1)

Negative control group (2)

1/1

 

1/2

1/3

1/4

1/5

1/6

2/1

2/2

2/3

 

Z1(3)

Z2(4)

Z1

Z2

Z1

Z2

Z1

Z2

Z1

Z2

Z1

Z2

Z1

Z2

Z1

Z2

Z1

Z2

0

<10(5)

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

<10

60

11

18

273

320

12

20

91

149

26

33

10

21

<10

<10

<10

<10

<10

<10

180

16

<10

244

172

18

<10

87

120

12

24

20

13

<10

<10

<10

<10

<10

<10

Figure 2: Immunogenicity of Inactivated Zika vaccine candidate (ZIKV strain SV0010/15) in Monkey by Plaque Reduction Neutralization Test 50 % (PRNT50)

Legend: (1) = They had injected by Inactivated ZIKV vaccine strain SV0010/15;

                     (2) = They had injected by adjuvant and PBS7.4;

                     (3) = Neutralized by ZIKV strain SV0010/15 (homologous strain);

                    (4) = Neutralized by ZIKV MR766 strain (heterologous strain);

                   (5)  PRNT value

Also, the neutralizing antibody were observed on day 60 and day 180 against ZIKV strain SV0010/15 (homologous strain) and ZIKV strain MR766 strain (heterologous strain) with about 31, 48 and 14, 34 respectively (Figure 2). 

Group (1)

Monkey code

Virus detection (2)

Virus isolation

(Virus titration) (3)

Viremia (day)

I

1/1

-

-

-

 

1/2

-

-

-

 

1/3

-

-

-

II

1/4

-

-

-

 

1/5

-

-

-

 

1/6

-

-

-

III (4)

2/1

+

+ (2.1 log10)

183

 

2/2

+

+ (1.8 log10)

184

 

 

 

2/3

+

+ (2.3 log10)

183

Table 2 Virus detection, isolation and titration after Challenging test in Cynomolgus monkeys

Legend: (1) = Group I and III were respectively challenged with ZIKV strain SV0010/15 (homologous strain) while Group II specimens were challenged by with ZIKV strain MR766 (heterologous strain);

(2) Virus detection by RT PCR;

(3) Virus isolation by C6/36, IFA and Virus titration by Plaque assay;

(4) Positive control challenge group;

Ultimately, all vaccinated monkeys were completely protected against ZIKV challenge by two strains of ZIKV, as demonstrated by the lack of detection of viral RNA in the serum samples but excepted the sham control macaques (Table 2).

Discussion

These preclinical results in small animal model showed the safety (dose) and immunogenicity of the inactivated Zika vaccine. The experiments in macaques confirmed the prior results in mice and could be extend them to Non-Human Primate model using vaccine doses and an administration route applicable to humans. Also, the optimized Zika vaccine adjuvanted with AlOOH provided complete 100% protection against two strains of Zika virus of Cynomolgus macaques 6 months after immunization. No specific adverse effects related to the vaccine was reported based on local and systemic observations [22]. Seroconversion was shown in all macaques including IgG/IgM while neutralizing antibody responses remained detectable at 6 months post immunization. This candidate vaccine is the first-generation Zika vaccine in Thailand. Also, it is compliant and deliver a high-quality vaccine. This new inactivated ZIKV vaccine quality candidate has a potential to be developed up to GMP pilot scale. Combined with its excellent performance in animal models this indicates that the vaccine would be appropriate for an accelerated development based on public demand.

Acknowledgements

We would like to thank Doctor Rome Buathong Burean of Epidemiology Department of Disease Control, Ministry of Public Health who provide Zika virus strain SV0010/15 and the Government Pharmaceutical Organization (GPO) who provide WHO Vero cell, some supported and staffs. Also, the authors thank the staffs of the Center for Vaccine Development Institute of Molecular Biosciences and Faculty of Veterinary Science Mahidol University who helped on this project. This project is supported by National Vaccine Institute (NVI) Ministry of Public Health. Dr Gonzalez was supported by ERP International LLC.

References

  1. Tham HW, Balasubramaniam V, Ooi MK, Chew MF.( 2018) Viral Determinants and Vector Competence of Zika Virus Transmission. Front Microbiol 9: 1040.
  2. Calvet GA, Santos FB, Sequeira PC.( 2016) Zika virus infection: epidemiology, clinical manifestations and diagnosis. Curr Opin Infect Dis 29: 459-466.
  3. Dick GW, Kitchen SF, Haddow AJ.( 1952) Zika virus Isolations and serological specificity.Trans R Soc Trop Med Hyg 46: 509–520.
  4. Gulland, A. (2016) Zika virus is a global public health emergency, declares WHO. BMJ: 352-657.
  5. Mlakar J, Korva M, Tul N, Popovic M, Poljšak-Prijatelj M, et al. ( 2016) Zika virus associated with microcephaly.N Engl J Med 374: 951-958.
  6. Costello A, Dua T, Duran P, Gülmezoglu M, Oladapo OT, et al. (2016) Defining the syndrome associated with congenital Zika virus infection. Bull World Health Organ 94: 406-406A.
  7. Parra B, Lizarazo J, Jiménez-Arango JA,  Zea-Vera  AF,  González-Manrique G,et al. (2016) Guillain–Barré Syndrome Associated with Zika Virus Infection in Colombia. N Engl J Med 375: 1513-1523.
  8. Pond WL. (1963) Arthropod-borne virus antibodies in sera from residents of South-East Asia. Trans R Soc Trop Med Hyg 57: 364-371.
  9. Fonseca K, Meatherall B, Zarra D, Drebot M, MacDonald J, et al. (2014) First case of Zika virus infection in a returning Canadian traveler. Am J Trop Med Hyg 91: 1035–1038.
  10. Buathong R, Hermann L, Thaisomboonsuk B, Rutvisuttinunt W, Klungthong C, et al. (2015) Detection of Zika Virus Infection in Thailand, 2012-2014. Am J Trop Med Hyg 93 :380-383.
  11. Pattnaik A, Sahoo BR, Pattnaik AK. (2020) Current Status of Zika Virus Vaccines: Successes and Challenges. Vaccines (Basel) 8: 266.
  12. Abbink P, Larocca RA, De La Barrera RA, Bricault CA, Moseley ET, et al. (2016) Protective efficacy of multiple vaccine platforms against Zika virus challenge in rhesus monkeys. Science 353: 1129-1132.
  13. Larocca RA, Abbink P, Peron JP, Zanotto PM, Iampietro MJ,et al. (2016) Vaccine protection against Zika virus from Brazil. Nature 536: 474-478.
  14. World Health Organization. Annex 6: Requirements for Japanese Encephalitis Vaccine (Inactivated) for Human Use. World Health Organization Technical Report Series, Vo.771, 1988.
  15. Sumathy K, Kulkarni B, Gondu RK, Ponnuru SK, Bonguram N, et al. (2017) Protective efficacy of Zika vaccine in AG129 mouse model. Sci Rep 7: 46375.
  16. Tio PH, Malasit P. (1995) Anti-dengue IgG detection by an indirect ELISA. Southeast Asian J Trop Med Public Health 26: 673-676.
  17. Innis BL, Nisalak A, Nimmannitya S, Kusalerdchariya S, Chongswasdi V, et al. (1989) An enzyme-linked  immunosorbent assay to characterize dengue infection where dengue and Japanese encephalitis co-circulate. Am J Trop Med. Hyg 40: 418-427.
  18. Shu, PY, Chen, LK., Chang SF, Yueh, YY, Chow L, et al. (2003) Comparison of capture immunoglobulin M (IgM) and IgG enzyme-linked immunosorbent assay (ELISA) and nonstructural protein NS1 serotype-specific IgG ELISA for differentiation of primary and secondary dengue virus infections. Clin Diagn Lab Immunol 10: 622-630.
  19. Russell PK, Nisalak A, Sukhavachana P, Vivona S. (1967) A plaque reduction test for dengue virus neutralizing antibodies. J Immunol 99: 285-290.
  20. Faye O, Dupressoir A, Weidmann M, Ndiaye M, Alpha Sall A, et al (2008) One-step RT-PCR for detection of Zika virus. J ClinVirol 43: 96-101.
  21. Henchal EA, McCown JM, Seguin MC, Gentry MK, Brandt WE. (1983) Rapid identification of dengue virus isolates by using monoclonal antibodies in an indirect immunofluorescence assay. Am J Trop Med Hyg 32: 164-169.
  22. Lecouturier V, Pavot V, Berry C, Donadieu A, de Montfort A, et al. (2020) An optimized purified inactivated Zika vaccine provides sustained immunogenicity and protection in cynomolgus macaques. NPJ Vaccines 5: 19.

Citation: Nitatpattana N (2022) Pneumococcal Conjugate Vaccines (PCVs) introduction in the Immunization Program and its Impact on Mortality under 5 years in Guyana, South America. J Vaccines Res Vaccin 8: 20.

Copyright: © 2022  Nitatpattana N, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

© 2022, Copyrights Herald Scholarly Open Access. All Rights Reserved!