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Tong J, Zhu C, Lai H, Feng C, Zhou D. Potent Neutralization Antibodies Induced by a Recombinant Trimeric Spike Protein Vaccine Candidate Containing PIKA Adjuvant for COVID-19. Vaccines (Basel) 2021; 9:296. [PMID: 33810026 PMCID: PMC8004863 DOI: 10.3390/vaccines9030296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/15/2021] [Accepted: 03/18/2021] [Indexed: 12/11/2022] Open
Abstract
The structures of immunogens that elicit the most potent neutralization antibodies to prevent COVID-19 infection are still under investigation. In this study, we tested the efficacy of a recombinant trimeric Spike protein containing polyI:C (PIKA) adjuvant in mice immunized by a 0-7-14 day schedule. The results showed that a Spike protein-specific antibody was induced at Day 21 with titer of above 50,000 on average, as measured by direct binding. The neutralizing titer was above 1000 on average, as determined by a pseudo-virus using monoclonal antibodies (40592-MM57 and 40591-MM43) with IC50 at 1 μg/mL as standards. The protein/peptide array-identified receptor-binding domain (RBD) was considered as immunodominant. No linear epitopes were found in the RBD, although several linear epitopes were found in the C-terminal domain right after the RBD and heptad repeat regions. Our study supports the efficacy of a recombinant trimeric Spike protein vaccine candidate for COVID-19 that is safe and ready for storage and distribution in developing countries.
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Affiliation(s)
- Jiao Tong
- Tongji University School of Medicine, Shanghai 200092, China; (J.T.); (C.Z.); (H.L.); (C.F.)
- Shanghai Pudong New Area Mental Health Center Affiliated with Tongji University School of Medicine, 165 Sanlin Road, Shanghai 200124, China
| | - Chenxi Zhu
- Tongji University School of Medicine, Shanghai 200092, China; (J.T.); (C.Z.); (H.L.); (C.F.)
- Shanghai Pudong New Area Mental Health Center Affiliated with Tongji University School of Medicine, 165 Sanlin Road, Shanghai 200124, China
| | - Hanyu Lai
- Tongji University School of Medicine, Shanghai 200092, China; (J.T.); (C.Z.); (H.L.); (C.F.)
- Shanghai Pudong New Area Mental Health Center Affiliated with Tongji University School of Medicine, 165 Sanlin Road, Shanghai 200124, China
| | - Chunchao Feng
- Tongji University School of Medicine, Shanghai 200092, China; (J.T.); (C.Z.); (H.L.); (C.F.)
- Shanghai Pudong New Area Mental Health Center Affiliated with Tongji University School of Medicine, 165 Sanlin Road, Shanghai 200124, China
| | - Dapeng Zhou
- Tongji University School of Medicine, Shanghai 200092, China; (J.T.); (C.Z.); (H.L.); (C.F.)
- Shanghai Pudong New Area Mental Health Center Affiliated with Tongji University School of Medicine, 165 Sanlin Road, Shanghai 200124, China
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Shi W, Kou Y, Xiao J, Zhang L, Gao F, Kong W, Su W, Jiang C, Zhang Y. Comparison of immunogenicity, efficacy and transcriptome changes of inactivated rabies virus vaccine with different adjuvants. Vaccine 2018; 36:5020-5029. [DOI: 10.1016/j.vaccine.2018.07.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 05/29/2018] [Accepted: 07/03/2018] [Indexed: 12/12/2022]
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Kalimuddin S, Wijaya L, Chan YFZ, Wong AWL, Oh HML, Wang LF, Kassim JA, Zhao J, Shi Z, Low JG. A phase II randomized study to determine the safety and immunogenicity of the novel PIKA rabies vaccine containing the PIKA adjuvant using an accelerated regimen. Vaccine 2017; 35:7127-7132. [PMID: 29174316 DOI: 10.1016/j.vaccine.2017.10.097] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/27/2017] [Accepted: 10/28/2017] [Indexed: 11/25/2022]
Abstract
BACKGROUND Human Rabies infection continues to be potentially fatal despite the availability of post-exposure prophylaxis with rabies vaccine. The PIKA Rabies vaccine adjuvant is a TLR3 agonist and has been shown to be safe and immunogenic in clinical phase I studies. METHODS We conducted a phase II, open label, randomized study in healthy adults to assess the safety and immunogenicity of the PIKA rabies vaccine under an accelerated regimen. 126 subjects were randomized into two groups: control vaccine classic regimen ("control-classic") and PIKA vaccine accelerated regimen ("PIKA-accelerated"). Subjects were followed up for safety and rabies virus neutralizing antibodies (RVNA). RESULTS Both the control and PIKA vaccines were generally well tolerated. 57.6% of subjects in the PIKA vaccine group, compared with 43.8% of subjects in the control-classic group, achieved the target RVNA titer of ≥0.5 IU/mL by Day 7. All subjects achieved the target RVNA titer by Day 14. The RVNA geometric mean titer at Day 7 was 0.60 IU/ml in the PIKA vaccine group and 0.39 IU/ml in the control-classic group. At Day 14, the RVNA geometric mean titer was 18.25 IU/ml in the PIKA-accelerated group and 19.24 IU/ml in the control-classic group. The median time taken to reach the target RVNA titer level of ≥0.5 IU/mL was 7.0 days (95% CI: 7.0-42.0 days) in the PIKA-accelerated group and 14.0 days (95% CI: 7.0-42.0 days) in the control-classic group. CONCLUSION The accelerated regimen using the investigational PIKA Rabies vaccine was well-tolerated and demonstrated non-inferior immunogenicity compared to the classic regimen using the commercially available vaccine in healthy adults. Clinical trial registry: The study was registered with clinicaltrials.gov (NCT02956421).
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Affiliation(s)
- Shirin Kalimuddin
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Limin Wijaya
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Yvonne F Z Chan
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Abigail W L Wong
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Helen M L Oh
- Division of Infectious Disease, Changi General Hospital, 2 Simei St 3, Singapore 529889, Singapore.
| | - Lin-Fa Wang
- Programme in Emerging Infectious Diseases, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore.
| | - Julaihabee A Kassim
- Yisheng Biopharma (Singapore) Pte. Ltd., 20 Maxwell Road, Maxwell House, 07-15A, Singapore 069113, Singapore.
| | - Jing Zhao
- Yisheng Biopharma (Singapore) Pte. Ltd., 20 Maxwell Road, Maxwell House, 07-15A, Singapore 069113, Singapore.
| | - Zhongkai Shi
- Yisheng Biopharma (Singapore) Pte. Ltd., 20 Maxwell Road, Maxwell House, 07-15A, Singapore 069113, Singapore.
| | - Jenny G Low
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
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Wijaya L, Tham CYL, Chan YFZ, Wong AWL, Li LT, Wang LF, Bertoletti A, Low JG. An accelerated rabies vaccine schedule based on toll-like receptor 3 (TLR3) agonist PIKA adjuvant augments rabies virus specific antibody and T cell response in healthy adult volunteers. Vaccine 2017; 35:1175-1183. [PMID: 28118938 DOI: 10.1016/j.vaccine.2016.12.031] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2016] [Revised: 12/14/2016] [Accepted: 12/14/2016] [Indexed: 01/04/2023]
Abstract
BACKGROUND Rabies is a fatal disease where post-exposure prophylaxis (PEP) is crucial in preventing infection. However, deaths even after appropriate PEP, have been reported. The PIKA Rabies vaccine adjuvant is a TLR3 agonist that activates B and T cells leading to a robust immune response. METHODS We conducted a phase I, open label, randomized study in healthy adults to assess the safety and immunogenicity of the PIKA Rabies vaccine and an accelerated vaccine regimen. Thirty-seven subjects were randomized into 3 groups: control vaccine classic regimen, PIKA vaccine classic regimen and PIKA vaccine accelerated regimen. Subjects were followed up for safety, rabies virus neutralizing antibodies (RVNA) and T cell responses. RESULTS Both the control and PIKA Rabies vaccine were well tolerated. All adverse events (AEs) were mild and self-limiting. Seventy-five percent of subjects in the PIKA accelerated regimen achieved a RVNA titer ⩾0.5IU/mL on day 7, compared to 53.9% in the PIKA classic regimen (p=0.411) and 16.7% in control vaccine classic regimen (p=0.012). The PIKA rabies vaccine elicited multi-specific rabies CD4 mediated T cell response already detectable ex vivo at day 7 after vaccination and that was maintained at day 42. CONCLUSION The investigational PIKA rabies vaccine was well tolerated and more immunogenic than the commercially available vaccine in healthy adults. Clinical trial registry: The study was registered with clinicaltrials.gov NCT02657161.
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Affiliation(s)
- Limin Wijaya
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Christine Y L Tham
- Singapore Institute for Clinical Sciences, Agency for Science Technology and Research (A*STAR), 30 Medical Drive, Singapore 117609, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, 28 Medical Drive, Singapore 117456, Singapore.
| | - Yvonne F Z Chan
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - Abigail W L Wong
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
| | - L T Li
- Yisheng Biopharma (Singapore) Pte. Ltd., 20 Maxwell Road, Maxwell House 07-15A, Singapore 069113, Singapore.
| | - Lin-Fa Wang
- Program in Emerging Infectious Diseases, DUKE-NUS Medical School, 8 College Road, Singapore 169857, Singapore.
| | - Antonio Bertoletti
- Program in Emerging Infectious Diseases, DUKE-NUS Medical School, 8 College Road, Singapore 169857, Singapore; Singapore Institute for Clinical Sciences, Agency for Science Technology and Research (A*STAR), 30 Medical Drive, Singapore 117609, Singapore.
| | - Jenny G Low
- Department of Infectious Diseases, Singapore General Hospital, 20 College Road, Singapore 169856, Singapore.
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Zhang Y, Zhang S, Li L, Hu R, Lin H, Liu H, Liu F, Shao H, Liu Y. Ineffectiveness of rabies vaccination alone for post-exposure protection against rabies infection in animal models. Antiviral Res 2016; 135:56-61. [PMID: 27737787 DOI: 10.1016/j.antiviral.2016.10.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2016] [Revised: 10/08/2016] [Accepted: 10/09/2016] [Indexed: 12/13/2022]
Abstract
Most reported vaccination failures among rabies-exposed patients were due to fail to timely co-administer rabies immunoglobulin (RIG). Considering that such protection failure might be caused by low antigen titers in the vaccine, scientists improved antigen titers to 4.0 IU or even higher, yet the failure remained. Therefore, it becomes vital to develop more efficacious vaccine against rabies. In our evaluation of a novel PIKA rabies vaccine, we used multiple animal models (beagles, golden hamsters and Kunming mice) to mimic post-exposure scenarios. All animals were challenged with wild-type rabies virus, followed by vaccination with either rabies vaccines commercially available or PIKA rabies vaccines. As 100% of animals survived after administration of traditional rabies vaccines and rabies immunoglobulin, 80% of animals survived with rabies immunoglobulin alone. Strikingly, animals receiving traditional rabies vaccines alone showed extremely low survival rates, indicating insignificant benefit for exposed animals (p > 0.05, compared to unvaccinated control groups). To the contrary, 40-80% of animals receiving the experimental PIKA rabies vaccines were protected (p < 0.05, compared to unvaccinated control groups). If the above results are fully confirmed, we may conclude that currently as high as 99% of post-exposure patients who are seeking protection against rabies, but only receiving rabies vaccination, could be meaningless.
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Affiliation(s)
- Yi Zhang
- Yisheng Biopharma Co., Ltd., Beijing, China
| | | | - Lietao Li
- Yisheng Biopharma Co., Ltd., Beijing, China
| | - Rongliang Hu
- Academy of Military Medical Sciences, Changchun, China
| | | | - Hua Liu
- Yisheng Biopharma Co., Ltd., Beijing, China
| | - Fang Liu
- Yisheng Biopharma Co., Ltd., Beijing, China
| | - Hui Shao
- Yisheng Biopharma Co., Ltd., Beijing, China
| | - Yuan Liu
- Yisheng Biopharma Co., Ltd., Beijing, China.
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A novel rabies vaccine based-on toll-like receptor 3 (TLR3) agonist PIKA adjuvant exhibiting excellent safety and efficacy in animal studies. Virology 2016; 489:165-72. [DOI: 10.1016/j.virol.2015.10.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 10/28/2015] [Accepted: 10/29/2015] [Indexed: 01/09/2023]
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Adjuvant PIKA protects hepatoma cells from dengue virus infection by promoting a TBK-1-dependent innate immune response. Arch Virol 2012; 158:829-38. [DOI: 10.1007/s00705-012-1556-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 10/16/2012] [Indexed: 10/27/2022]
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Gai WW, Zhang Y, Zhou DH, Chen YQ, Yang JY, Yan HM. PIKA provides an adjuvant effect to induce strong mucosal and systemic humoral immunity against SARS-CoV. Virol Sin 2011; 26:81-94. [PMID: 21468931 PMCID: PMC7091335 DOI: 10.1007/s12250-011-3183-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Accepted: 02/18/2011] [Indexed: 12/30/2022] Open
Abstract
Severe Acute Respiratory Syndrome (SARS) is a deadly infectious disease caused by SARS Coronavirus (SARS-CoV). Inactivated SARS-CoV has been explored as a vaccine against SARS-CoV. However, safe and potent adjuvants, especially with more efficient and economical needle-free vaccination are always needed more urgently in a pandemic. The development of a safe and effective mucosal adjuvant and vaccine for prevention of emergent infectious diseases such as SARS will be an important advancement. PIKA, a stabilized derivative of Poly (I:C), was previously reported to be safe and potent as adjuvant in mouse models. In the present study, we demonstrated that the intraperitoneal and intranasal co-administration of inactivated SARS-CoV vaccine together with this improved Poly (I:C) derivative induced strong anti-SARS-CoV mucosal and systemic humoral immune responses with neutralizing activity against pseudotyped virus. Although intraperitoneal immunization of inactivated SARS-CoV vaccine alone could induce a certain level of neutralizing activity in serum as well as in mucosal sites, co-administration of inactivated SARS-CoV vaccine with PIKA as adjuvant could induce a much higher neutralizing activity. When intranasal immunization was used, PIKA was obligatorily for inducing neutralizing activity in serum as well as in mucosal sites and was correlated with both mucosal IgA and mucosal IgG response. Overall, PIKA could be a good mucosal adjuvant candidate for inactivated SARS-CoV vaccine for use in possible future pandemic.
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Affiliation(s)
- Wei-wei Gai
- Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan 430072, China
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Jin B, Sun T, Yu XH, Liu CQ, Yang YX, Lu P, Fu SF, Qiu HB, Yeo AET. Immunomodulatory effects of dsRNA and its potential as vaccine adjuvant. J Biomed Biotechnol 2010; 2010:690438. [PMID: 20671921 PMCID: PMC2910503 DOI: 10.1155/2010/690438] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2009] [Accepted: 05/09/2010] [Indexed: 02/07/2023] Open
Abstract
dsRNA can be detected by pattern recognition receptors, for example, TLR3, MDA-5, NLRP3 to induce proinflammatory cytokines responsible for innate/adaptive immunity. Recognized by endosomal TLR3 in myeloid DCs (mDCs), dsRNA can activate mDCs into mature antigen presenting cells (mAPCs) which in turn present antigen epitopes with MHC-I molecules to naïve T cells. Coadministration of protein and synthetic dsRNA analogues can elicit an antigen-specific Th1-polarized immune response which stimulates the CD8+ CTL response and possibly dampen Th17 response. Synthetic dsRNA analogues have been tested as vaccine adjuvant against viral infections in animal models. However, a dsRNA receptor, TLR3 can be expressed in tumor cells while other members of TLR family, for example, TLR4 and TLR2 have been shown to promote tumor progression, metastasis, and chemoresistance. Thus, the promising potential of dsRNA analogues as a tumor therapeutic vaccine adjuvant should be evaluated cautiously.
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Affiliation(s)
- Bo Jin
- Department of Digestive Diseases, Naval General Hospital, 6 Fucheng Rd., Beijing 100048, China.
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Abstract
Human rabies cases in China have continued to increase in recent years, reaching a new peak in 2007. Parallel with an increase in human rabies deaths, a number of animal species with rabies have been reported in the majority of rabies-endemic areas. In this report, the occurrence, status, and control of rabies in both humans and animals are reviewed. Vaccines and immunoglobulin for human and animal use and postexposure prophylaxis for human are also summarized. The current strategies for rabies elimination in China are presented.
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Affiliation(s)
- Ronglinag Hu
- Academy of Military Medical Sciences, Changchun, People's Republic of China.
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de Souza Matos DC, Marcovistz R, Neway T, Vieira da Silva AM, Alves EN, Pilet C. Immunostimulatory effects of polar glycopeptidolipids of Mycobacterium chelonae for inactivated rabies vaccine. Vaccine 2000; 18:2125-31. [PMID: 10715527 DOI: 10.1016/s0264-410x(99)00544-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Humoral and cellular immune responses were analyzed with Fuenzalida-Palacios rabies vaccine associated with pGPL-Mc, polar glycopeptidolipids extracted from Mycobacterium chelonae, aiming at its use as adjuvant. These results were compared to those obtained with BCG, a well-known immunostimulator, under the same conditions. Rabies vaccine plus pGPL-Mc (2.5 mg/kg) induced a significant increase in serum neutralizing activity, in vitro lymphocyte proliferation (spontaneous, specific and mitogen stimulation) and delayed type hypersensibility. In addition, pGPL-Mc, as well as BCG, enhanced the vaccine potency. Our results support further studies to encourage the use of pGPL-Mc as an immunostimulator of veterinary vaccines, before consideration for human vaccines.
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Megid J, Kaneno R. Natural killer activity in mice infected with rabies virus and submitted to P. acnes (Propionibacterium acnes) as immunomodulator. Comp Immunol Microbiol Infect Dis 2000; 23:91-7. [PMID: 10670698 DOI: 10.1016/s0147-9571(99)00061-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The natural killer (NK) activity and lethality were evaluated in swiss mice experimentally infected with street rabies virus and submitted to immunomodulation by P. acnes (formerly Corynebacterium parvum). The infected animals were sacrificed at different times and spleen non-adherent cells were obtained through ficoll-hypaque gradient and depletion of glass-adherent cells. Immunosuppression was observed in rabies virus infected mice correlated with lower NK activity in clinically ill animals. Higher NK activity and percentual of survival were observed in the group submitted to P. acnes. The increased survival correlated with higher NK activity induced by P. acnes suggests a protective role of this natural barrier against rabies virus infection in mice.
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Affiliation(s)
- J Megid
- Faculty of Veterinary Medicine, Department of Veterinary Hygiene and Public Health, UNESP, Botucatu, SP, Brazil.
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Megid J, Peraçolli MT, Curi PR, Zanetti CR, Cabrera WH, Vassao R, Ito FH. Effect of vaccination and the immunomodulators "bacillus of Calmette-Guérin, avridine and Propionibacterium acnes" on rabies in mice. Comp Immunol Microbiol Infect Dis 1998; 21:305-18. [PMID: 9775360 DOI: 10.1016/s0147-9571(98)00005-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Responses of vaccination and treatment to immunomodulators against rabies in mice were evaluated through macrophage inhibition factor (MIF), intra-pad inoculation (IPI) and serum neutralization (SN) tests and by the detection of gamma-interferon (IFN-gamma). Onco-BCG, Avridine and Propionibacterium acnes were administered to groups of mice. Higher survival rates were found in animals treated with P. acnes. Lower levels of IFN-gamma were observed in the groups of infected and vaccinated mice. The IPI was not effective on detecting the response of delayed-type hypersensitivity. Vaccine induced in the infected animals a more intense response to MIF reaction.
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Affiliation(s)
- J Megid
- Department of Veterinary Hygiene and Public Health, FMVZ-UNESP, Botucatu-SP, Brazil.
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Castignolles N, Morgeaux S, Gontier-Jallet C, Samain D, Betbeder D, Perrin P. A new family of carriers (biovectors) enhances the immunogenicity of rabies antigens. Vaccine 1996; 14:1353-60. [PMID: 9004445 DOI: 10.1016/s0264-410x(96)00043-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Biovectors (BV) are a new family of protein carriers. They are nanoparticles of polymerized polysaccharides substituted with phosphate residues and surrounded by covalently bound lipid molecules (palmitic acid). The effect of BV was tested on the immunogenicity of rabies antigens. Biovectors enhanced the production of antibody induced by both rabies glycoprotein and ribonucleoprotein. Moreover, they enhanced the protective activity of an experimental rabies vaccine composed of inactivated and purified virus. The isotype profile of antibody produced in vivo was not modified when BV were mixed with rabies antigens. To clarify the mechanism of the adjuvant/ immunostimulation effect of BV, two types of approach were used: (1) analysis of the antibody response when antigen and BV were injected separately; (2) determination of the nature of cells involved in the proliferation in vitro of murine splenocytes in the presence of BV. The enhancing effect of BV on antibody production was highest when mixed with antigens. In vitro BV induced the proliferation of B cells. These findings suggest that BV have immunostimulating properties in addition to their probable depot and/or antigen-presentation effect which explain in part their adjuvant activity.
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Affiliation(s)
- N Castignolles
- Laboratoire des Lyssavirus, Institut Pasteur, Paris, France
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