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Kouiavskaia D, Mirochnitchenko O, Troy S, Chumakov K. Antigenic diversity of type 1 polioviruses and its implications for the efficacy of polio vaccines. Vaccine 2023; 41:2147-2154. [PMID: 36828716 DOI: 10.1016/j.vaccine.2023.01.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 01/12/2023] [Accepted: 01/15/2023] [Indexed: 02/24/2023]
Abstract
Inactivated Polio Vaccines (IPV) and live Oral Polio Vaccine (OPV) were introduced in the mid-20th century, and their coordinated worldwide use led to almost complete elimination of the disease, with only one serotype of poliovirus remaining endemic in just two countries. Polio eradication will lead to discontinuation of OPV use and its replacement with IPV or other vaccines that are currently under development that will need to be tested in clinical trials. Despite decades of research, questions remain about the serological correlates of polio vaccine efficacy, specifically whether the vaccines are equally protective against immunologically different strains of the same serotype. The absence of significant morbidity does not allow use of a protection endpoint in clinical trials, so the answer could be obtained only by using surrogate markers such as immunogenicity. In this study, a panel of wild and vaccine-derived polioviruses of serotype 1 were tested in neutralization assays with sera from vaccine-immunized individuals. The results demonstrated that there was a significant difference in titers of neutralizing antibodies in human sera when measured against different strains. When measured with a homologous strain used for vaccine manufacture all subjects had detectable levels of antibodies, while neutralization tests with some heterologous strains failed to detect neutralizing antibodies in a number of subjects. Administration of a booster dose of IPV led to a significant increase in neutralizing titers against all strains. Results of the experiments using animal sera, performed to obtain more information on protectivity of neutralizing antibodies against heterologous strains, were consistent with the results obtained in the assays using human sera. These results are discussed in the context of serological biomarkers of protection against poliomyelitis, suggesting that potency of vaccines made from serologically different strains should be determined against both homologous and heterologous challenge viruses.
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Affiliation(s)
| | | | - Stephanie Troy
- Center for Drugs Evaluation and Research, Food and Drug Administration, Silver Spring, MD, USA
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2
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Manu M, Singha Mahapatra C, Pachauri R, Ompreethi B, Dhar P. Evaluation of an alternative method for determination of Protective Dose 50 of Classical swine fever vaccines. Virology 2023; 581:139-144. [PMID: 36963269 DOI: 10.1016/j.virol.2023.02.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2022] [Revised: 02/24/2023] [Accepted: 02/27/2023] [Indexed: 03/09/2023]
Abstract
Classical Swine Fever (CSF) is still one of the most economically important viral diseases of pigs. The disease is controlled by vaccination in the endemic countries. Hence, availability or supply of efficacious and potent vaccine in the field settings is of utmost importance. Currently, as per requirement of any Pharmacopoea, a CSF vaccine must contain 100 PD50/dose which is determined by vaccinating pigs at 1/40th and 1/160th dilution of each dose followed by virulent challenge at 28 days post vaccination (dpv). Here, the control and the unprotected groups succumb to disease and need to be euthanized. Moreover, such challenge experiments are not feasible for each batch of the vaccine. In this communication, an alternate method of PD50 dose calculation of live-attenuated CSF vaccines by measuring Serum Neutralizing Titre i.e Fluorescent Antibody Virus Neutralization (FAVN) titre of the vaccinated pigs at 28 dpv was established. This alternative method do not require the vaccinated pigs to be challenged. Serum samples, generated out of QC testing of eight batches of CSF vaccines in the laboratory, were tested and found that pigs having FAVN titre ≥10 were protected against challenge. Initially this test was optimized in serum samples of 12 animals and then validated with another 56 serum samples. It was found that the alternate method is 100% correlating with the challenge experiment. Thus, based on FAVN titre of the vaccinated animal serum, it can be predicted whether the pigs would or would not come through the challenge infection. Using the predicted status (protected/succumbed), PD50 can be calculated by applying Reed and Muench formula, hence alternate method can be used as routine QC test for potency of CSF vaccines. The newly developed assay was specific since no signal was observed in controls.
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Affiliation(s)
- M Manu
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, 243122, Uttar Pradesh, India
| | - Chayna Singha Mahapatra
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, 243122, Uttar Pradesh, India
| | - Richa Pachauri
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, 243122, Uttar Pradesh, India
| | - B Ompreethi
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, 243122, Uttar Pradesh, India
| | - Pronab Dhar
- Division of Biological Standardization, ICAR-Indian Veterinary Research Institute, Izatnagar, 243122, Uttar Pradesh, India.
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3
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Rech F, De Ricco R, Giannini S, Nompari L, Paludi M, Berti S, Parlati C, Cianetti S, Berti F. Glycoconjugate content quantification to assess vaccine potency: A simplified approach. Biologicals 2022; 76:10-14. [PMID: 35264299 DOI: 10.1016/j.biologicals.2022.02.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 01/12/2022] [Accepted: 02/25/2022] [Indexed: 11/02/2022] Open
Abstract
Several glycoconjugate vaccines have been licensed or are currently in clinical development to prevent bacterial infections. Here we report the development of a single analytical assay to quantify the conjugated saccharide content, as alternative to two separated total and free (unconjugated) saccharide assays used so far, for a quadrivalent conjugate vaccine containing meningococcal serogroup A polysaccharide (α-1,6-linked N-acetylmannosamine phosphate repeating unit partly O-acetylated at position C3 or C4) coupled with CRM197 protein. The results confirm a high linear correlation among the two approaches (conjugated saccharide content vs. difference of total saccharide and free saccharide). Conjugated saccharide content estimation is therefore demonstrated to be a suitable method to monitor the product quality of vaccines containing meningococcal serogroup A conjugate antigen, in the final filled presentation as demonstrated here and potentially on the bulk conjugate before formulation.
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Leibovici Weissman Y, Cooper L, Sternbach N, Ashkenazi-Hoffnung L, Yahav D. Clinical efficacy and safety of high dose trivalent influenza vaccine in adults and immunosuppressed populations - A systematic review and meta-analysis. J Infect 2021; 83:444-451. [PMID: 34425161 DOI: 10.1016/j.jinf.2021.08.028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 08/14/2021] [Accepted: 08/17/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVES Influenza is associated with significant morbidity and mortality, especially in older and immunocompromised patients. Few data are available on the clinical benefit of high dose trivalent influenza vaccine (TIV). We aimed to assess the clinical efficacy and safety of high dose TIV. METHODS We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), evaluating high dose versus standard dose TIV for prevention of seasonal influenza in adult population. Primary outcome was laboratory-confirmed influenza. Subgroups analyses included older adults and immunocompromised patients. RESULTS We included 16 trials, 47,857 patients; 10 included older adults and three immunocompromised patients. Laboratory confirmed influenza was significantly reduced with high dose TIV (relative risk 0.76, 95% confidence interval 0.64 to 0.9). This outcome stemmed mainly from one trial in older adults. Specifically, A(H3N2) laboratory confirmed influenza, but not A(H1N1) or B lineages, was reduced. No difference in mortality or hospitalizations was demonstrated. Immunological response was significantly higher with high dose vaccine. Serious adverse events were significantly less common in the high dose group. CONCLUSIONS High dose TIV lowers the rates of laboratory confirmed influenza, mainly A (H3N2), in older adults vs. standard dose. Further studies should address immunocompromised patients and report clinical outcomes.
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Affiliation(s)
- Yaara Leibovici Weissman
- Internal medicine E, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel; Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel.
| | - Lisa Cooper
- Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel; Department of acuter geriatrics, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Neta Sternbach
- Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel; Internal medicine D, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Liat Ashkenazi-Hoffnung
- Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel; Day Hospitalization Department and Infectious Diseases Unit, Schneider Childrens Medical Center of Israel, Petah Tikva, Israel
| | - Dafna Yahav
- Sackler School of Medicine, Tel Aviv University, Ramat Aviv, Israel; Infectious Diseases Unit, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
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5
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Ming M, Caterini J, Ettorre L, Tang M, Schreiber M, Salha D, Gisonni-Lex L. Replacing the in vivo toxin challenge test with an in vitro assay for assessment of potency for diphtheria toxoid containing vaccines. Biologicals 2020; 68:19-25. [PMID: 33067107 DOI: 10.1016/j.biologicals.2020.09.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 08/17/2020] [Accepted: 09/21/2020] [Indexed: 10/23/2022] Open
Abstract
Replacement of the potency tests for diphtheria vaccines is a high priority for the international initiative to reduce, refine, and replace animal use in vaccine testing. Diphtheria toxoid containing vaccine products marketed in the US currently require potency testing by the United States Public Health Service (USPHS) test, which includes an in vivo passive protection test with a diphtheria toxin challenge. Here we describe an in vitro Diphtheria Vero Cell (DVC) assay which combines the immunization approach from the USPHS test and the use of a cell based neutralization assay for serological testing of vaccine potency. The DVC assay reduces the overall number of animals used compared to other serological potency tests and eliminates the in vivo toxin challenge used in the US test. The DVC assay can be used to test vaccine products with a low or high diphtheria toxoid dose. It has been optimized and validated for use in a quality control testing environment. Results demonstrate similar sera antibody unitage as well as agreement between the serum neutralization values determined using the USPHS test and the DVC assay and thus support the use of the DVC assay for routine and stability testing for diphtheria toxoid containing vaccine products.
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Affiliation(s)
- Marin Ming
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada.
| | - Judy Caterini
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
| | - Luciano Ettorre
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
| | - Mei Tang
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
| | - Martha Schreiber
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
| | - Danielle Salha
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
| | - Lucy Gisonni-Lex
- Sanofi Pasteur, Analytical Sciences Department, 1755 Steeles Avenue West, Toronto, ON, Canada
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Takahashi H, Fujimoto T, Horikoshi F, Uotani T, Okutani M, Shimasaki N, Hamamoto I, Odagiri T, Nobusawa E. Determination of the potency of a cell-based seasonal quadrivalent influenza vaccine using a purified primary liquid standard. Biologicals 2020; 68:32-39. [PMID: 33023810 DOI: 10.1016/j.biologicals.2020.09.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 09/04/2020] [Accepted: 09/06/2020] [Indexed: 10/23/2022] Open
Abstract
In Japan, the practical application of completely cell-based seasonal influenza vaccines is under consideration. Considering the good correlation between the immunogenicity of egg-based influenza vaccines and the hemagglutinin (HA) content determined by the single radial immunodiffusion (SRD) assay, we determined the potency of the first cell-based quadrivalent vaccine experimentally generated in Japan using the SRD assay in this study. A primary liquid standard (PLS) and reference antigen were generated from the purified vaccine virus, and a sheep antiserum was produced against the HA of the vaccine virus. Since the purity of the PLS affects the reliability of vaccine potency testing, the purification steps are significant. We successfully prepared a purified PLS nearly free of cell debris. The HA content in the PLS was first estimated from the total amount of viral protein and the percentage of HA content determined by SDS-PAGE analysis. The HA content in the reference antigen was calibrated to that in the PLS via the SRD assay. The vaccine potency, that is, the HA content in each vaccine, was finally measured using the corresponding reference antigen. Ultimately, the measured vaccine potency of the monovalent vaccine was similar to that of the quadrivalent vaccine.
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Affiliation(s)
- Hitoshi Takahashi
- Influenza Virus Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Takao Fujimoto
- The Research Foundation for Microbial Diseases of Osaka University (BIKEN), Kagawa, Japan
| | - Fumiaki Horikoshi
- The Research Foundation for Microbial Diseases of Osaka University (BIKEN), Kagawa, Japan
| | - Tae Uotani
- The Research Foundation for Microbial Diseases of Osaka University (BIKEN), Kagawa, Japan
| | - Mie Okutani
- The Research Foundation for Microbial Diseases of Osaka University (BIKEN), Kagawa, Japan
| | - Noriko Shimasaki
- Influenza Virus Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Itsuki Hamamoto
- Influenza Virus Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Takato Odagiri
- Influenza Virus Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan
| | - Eri Nobusawa
- Influenza Virus Research Center, National Institute of Infectious Diseases (NIID), Tokyo, Japan.
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Davis H, Dow T, Isopi L, Blue JT. Examination of the effect of agitation on the potency of the Ebola Zaire vaccine rVSVΔG-ZEBOV-GP. Vaccine 2020; 38:2643-5. [PMID: 32081445 DOI: 10.1016/j.vaccine.2020.02.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 01/31/2020] [Accepted: 02/02/2020] [Indexed: 12/18/2022]
Abstract
The Ebolavirus vaccine (rVSVΔG-ZEBOV-GP) is stored at -80 to -60 °C and should be kept frozen for transport. Due to significant logistical challenges, frozen transport is not feasible for some remote locations. To determine if local distribution at 2-8 °C is a potential option for these locations, a study was conducted to evaluate the impact of agitation on the thawed vaccine. After up to 7 days of constant agitation, no impact on vaccine potency was evident for the agitated vaccine versus the corresponding vaccine kept stationary at 2-8 °C. In conclusion, in-country transport of the Ebolavirus vaccine, rVSVΔG-ZEBOV-GP, at 2-8 °C appears to be a feasible option for those remote locations where significant logistical challenges prohibit transporting the vaccine at -80 to -60 °C.
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Kouiavskaia D, Puligedda RD, Dessain SK, Chumakov K. Universal ELISA for quantification of D-antigen in inactivated poliovirus vaccines. J Virol Methods 2020; 276:113785. [PMID: 31765719 DOI: 10.1016/j.jviromet.2019.113785] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/19/2019] [Accepted: 11/20/2019] [Indexed: 11/20/2022]
Abstract
To address the biosafety and biosecurity concerns related to the manufacture of inactivated polio vaccine (IPV), several manufacturers started producing it from attenuated Sabin strains. Slight immunological differences between wild and attenuated strains create a challenge for testing IPV potency, which is defined as the content of protective D-antigen determined in an ELISA test. Some ELISA reagents selected for testing conventional IPV made from wild strains (cIPV) may not be suitable for testing Sabin IPV (sIPV). This paper describes an ELISA procedure using human monoclonal antibodies selected to capture equally well both wild and attenuated strains of poliovirus. A unique monoclonal antibody neutralizing all three serotypes of poliovirus was used as the detection antibody. The method was shown to detect only D-antigen of both conventional and Sabin IPV and to be strictly serotype-specific. The method is highly sensitive and robust and produces linear results in a wide range of concentrations. We have also found that reference standards used for measuring potency of cIPV and sIPV must be made from respective vaccines. This makes it impossible to cross-calibrate potency reagents made from heterologous vaccine and requires the establishment of a new unit to measure potency of sIPV that is different from conventional D-antigen unit.
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Okinaka K, Akeda Y, Kurosawa S, Fuji S, Tajima K, Oishi K, Fukuda T. Pneumococcal polysaccharide vaccination in allogeneic hematopoietic stem cell transplantation recipients: a prospective single-center study. Microbes Infect 2017; 19:553-559. [PMID: 28965937 DOI: 10.1016/j.micinf.2017.08.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2017] [Revised: 08/02/2017] [Accepted: 08/21/2017] [Indexed: 01/04/2023]
Abstract
Few studies have evaluated the response of allogeneic hematopoietic stem cell transplantation [allo-HSCT] recipients to pneumococcal polysaccharide vaccine-23 [PPSV23] in the modern transplant era when more elderly patients undergo allo-HSCT. We administered a single dose of PPSV23 to 30 allo-HSCT recipients and evaluated serotype-specific antibody responses using IgG measured by enzyme-linked immunosorbent assay and opsonophagocytic assay [OPA] titers in a multiplexed opsonophagocytic killing assay. The median patient age was 54 years [range, 23-68], and the interval from allo-HSCT to vaccination was 756 days [range, 389-1903]. No severe adverse effects were observed. The median positive response rates at 1 month and 1 year post-vaccination for the 7 serotypes measured by IgG were the same at 43% [range, 33-57], while those for 8 serotypes measured by OPA were 72% [range, 55-86] and 55% [range, 52-62], respectively. Peripheral blood stem cell transplantation improved vaccine response based on OPA titers at 1 month post-vaccination. During the median follow-up period of 1135 days post-vaccination, one patient developed pneumococcal bacteremia at 998 days. Our study suggests that PPSV23 vaccination in allo-HSCT recipients is safe and may result in a serological response.
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Affiliation(s)
- Keiji Okinaka
- Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, Japan
| | - Yukihiro Akeda
- Department of Infection Control and Prevention, Osaka University Graduate School of Medicine, 3-1 Yamadaoka, Suita, Osaka, Japan; Research Institute for Microbial Diseases, Osaka University, 2-15 Yamadaoka, Suita, Osaka, Japan
| | - Saiko Kurosawa
- Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, Japan
| | - Shigeo Fuji
- Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, Japan
| | - Kinuko Tajima
- Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, Japan
| | - Kazunori Oishi
- Infectious Diseases Surveillance Center, National Institute of Infectious Diseases, 1-23-1 Toyama, Shinjuku-ku, Tokyo, Japan
| | - Takahiro Fukuda
- Department of Hematopoietic Stem Cell Transplantation, National Cancer Center Hospital, 5-1-1 Tsukiji, Chuo-ku, Tokyo, Japan.
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Khorasani A, Madadgar O, Soleimanjahi H, Keyvanfar H, Mahravani H. Evaluation of the efficacy of a new oil-based adjuvant ISA 61 VG FMD vaccine as a potential vaccine for cattle. Iran J Vet Res 2016; 17:8-12. [PMID: 27656222 PMCID: PMC4898013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Revised: 10/27/2015] [Accepted: 11/11/2015] [Indexed: 06/06/2023]
Abstract
Foot-and-mouth disease is an important viral disease of cloven-hoofed animals. Inactivated whole particle virus vaccines are still widely used in prophylactic vaccination campaigns. The choice of adjuvant is a very important factor in enhancing immune responses and the efficacy of inactivated vaccines. Montanide ISA 61 VG is a new ready-to-use mineral oil-based adjuvant developed by SEPPIC Inc. (SEPPIC, France) with high-potential immune responses needed for clinical protection against FMD infection. In this study, we compared the efficacy of two FMD vaccines either formulated with the new oil-based adjuvant ISA 61 VG and saponin, or with aluminum hydroxide gel and saponin. Both vaccines contained the same antigen payloads of O2010/IR. Two groups of 15 naive cattle received a single vaccination with different doses (full dose, 1/3 dose and 1/9 dose) to calculate their PD50 (50% protective dose) after being challenged with the homologous virulent virus. The mean neutralizing antibody titer was determined at 0, 7, 14 and 21 days after vaccination, measured by a micro neutralization test. The new vaccine improved humoral immune responses by 19%, while inducing a higher geometric mean. The titer for neutralizing antibodies was 2.91 log10 compared to the alum-gel based adjuvant vaccine which was 2.44 log10 (P-value=0.1782). The new vaccine showed a PD50 value of 10.05 as compared to a PD50 value of 4.171, respectively. According to the results, the FMD vaccine formulated with the new oil adjuvant, ISA 61 VG, shows potential as an alternative vaccine for routine and emergency vaccinations in the FMD enzootic region.
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Affiliation(s)
- A. Khorasani
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - O. Madadgar
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - H. Soleimanjahi
- Department of Virology, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
| | - H. Keyvanfar
- Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Tehran, Iran
| | - H. Mahravani
- Department of FMD Vaccine Production, Razi Vaccine and Serum Research Institute, Karaj, Iran
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Abstract
The particular virulence of Plasmodium falciparum manifests in diverse severe malaria syndromes as cerebral malaria, severe anemia and placental malaria. The cause of both the severity and the diversity of infection outcome, is the ability of the infected erythrocyte (IE) to bind a range of different human receptors through Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) on the surface of the infected cell. As the var genes encoding the large PfEMP1 antigens are extensively polymorphic, vaccine development strategies are focused on targeting the functional binding epitopes. This involves identification of recombinant fragments of PfEMP1s that induce antibodies, which hinder the adhesion of the IE to a given receptor or tissue. Different assays to measure the blocking of adhesion have been described in the literature, each with different advantages. This chapter describes a high-throughput assay used in the preclinical and clinical development of a VAR2CSA based vaccine against placental malaria.
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Affiliation(s)
- Morten A Nielsen
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, CSS Building 22/23, Øster Farimagsgade 5, 2099, Copenhagen K, 1014, Denmark.
| | - Ali Salanti
- Centre for Medical Parasitology, Department of International Health, Immunology and Microbiology, Faculty of Health and Medical Sciences, University of Copenhagen, CSS Building 22/23, Øster Farimagsgade 5, 2099, Copenhagen K, 1014, Denmark.
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