1
|
Cao Y, Hayashi CTH, Araujo MDS, Tripathi AK, Andrade AO, Medeiros JF, Vinetz J, Kumar N. Evaluation of combination vaccines targeting transmission of Plasmodium falciparum and P. vivax. Vaccine 2024; 42:126140. [PMID: 39033079 PMCID: PMC11338703 DOI: 10.1016/j.vaccine.2024.07.041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2024] [Revised: 07/02/2024] [Accepted: 07/12/2024] [Indexed: 07/23/2024]
Abstract
Transmission-blocking vaccines interrupting malaria transmission within mosquitoes represent an ideal public health tool to eliminate malaria at the population level. Plasmodium falciparum and P. vivax account for more than 90% of the global malaria burden, co-endemic in many regions of the world. P25 and P48/45 are two leading candidates for both species and have shown promising transmission-blocking activity in preclinical and clinical studies. However, neither of these target antigens as individual vaccines has induced complete transmission inhibition in mosquitoes. In this study, we assessed immunogenicity of combination vaccines based on P25 and P48/45 using a DNA vaccine platform to broaden vaccine specificity against P. falciparum and P. vivax. Individual DNA vaccines encoding Pvs25, Pfs25, Pvs48/45 and Pfs48/45, as well as various combinations including (Pvs25 + Pvs48/45), (Pfs25 + Pfs48/45), (Pvs25 + Pfs25), and (Pvs48/45 + Pfs48/45), were evaluated in mice using in vivo electroporation. Potent antibody responses were induced in mice immunized with individual and combination DNA vaccines, and specific antibody responses were not compromised when combinations of DNA vaccines were evaluated against individual DNA vaccines. The anti-Pvs25 IgG from individual and combination groups revealed concentration-dependent transmission-reducing activity (TRA) in direct membrane feeding assays (DMFA) using blood from P. vivax-infected donors in Brazil and independently in ex vivo MFA using Pvs25-transgenic P. berghei. Similarly, anti-Pfs25 and anti-Pfs48/45 IgGs from mice immunized with Pfs25 and Pfs48/45 DNA vaccines individually and in various combinations revealed antibody dose-dependent TRA in standard membrane feeding assays (SMFA) using culture-derived P. falciparum gametocytes. However, antibodies induced by immunization with Pvs48/45 DNA vaccines were ineffective in DMFA and require further vaccine construct optimization, considering the possibility of induction of both transmission-blocking and transmission-enhancing antibodies revealed by competition ELISA. These studies provide a rationale for combining multiple antigens to simultaneously target transmission of malaria caused by P. falciparum and P. vivax.
Collapse
MESH Headings
- Malaria Vaccines/immunology
- Malaria Vaccines/administration & dosage
- Animals
- Malaria, Falciparum/prevention & control
- Malaria, Falciparum/transmission
- Malaria, Falciparum/immunology
- Plasmodium falciparum/immunology
- Plasmodium falciparum/genetics
- Plasmodium vivax/immunology
- Plasmodium vivax/genetics
- Malaria, Vivax/prevention & control
- Malaria, Vivax/transmission
- Malaria, Vivax/immunology
- Mice
- Vaccines, DNA/immunology
- Vaccines, DNA/administration & dosage
- Antibodies, Protozoan/immunology
- Antibodies, Protozoan/blood
- Female
- Vaccines, Combined/immunology
- Vaccines, Combined/administration & dosage
- Antigens, Protozoan/immunology
- Antigens, Protozoan/genetics
- Protozoan Proteins/immunology
- Protozoan Proteins/genetics
- Mice, Inbred BALB C
- Humans
Collapse
Affiliation(s)
- Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington D.C., USA
| | - Clifford T H Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington D.C., USA
| | - Maisa da Silva Araujo
- Plataforma de Produção e Infecção de Vetores da Malária, Laboratório de Entomologia - FIOCRUZ RO, Rua da Beira 7671, CEP 76812-245 Porto Velho RO, Brazil; Programa de Pós-Graduação em Saúde Pública, Faculdade de Saúde Pública, Universidade Federal de São Paulo, São Paulo 01246-904, SP, Brazil
| | - Abhai K Tripathi
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, USA
| | - Alice Oliveira Andrade
- Plataforma de Produção e Infecção de Vetores da Malária, Laboratório de Entomologia - FIOCRUZ RO, Rua da Beira 7671, CEP 76812-245 Porto Velho RO, Brazil; Programa de Pós-Graduação em Saúde Pública, Faculdade de Saúde Pública, Universidade Federal de São Paulo, São Paulo 01246-904, SP, Brazil
| | - Jansen Fernandes Medeiros
- Plataforma de Produção e Infecção de Vetores da Malária, Laboratório de Entomologia - FIOCRUZ RO, Rua da Beira 7671, CEP 76812-245 Porto Velho RO, Brazil; Programa de Pós-Graduação em Biologia Experimental, Fundação Universidade Federal de Rondônia, Fiocruz Rondônia 76812-245, Brazil
| | - Joseph Vinetz
- Section of Infectious Diseases, Department of Internal Medicine, Yale School of Medicine, New Haven, CT, USA; Department of Cellular and Molecular Sciences, Faculty of Sciences, and Alexander von Humboldt Institute of Tropical Medicine, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington D.C., USA.
| |
Collapse
|
2
|
Cao Y, Hayashi CTH, Kumar N. A Novel Ex Vivo Assay to Evaluate Functional Effectiveness of Plasmodium vivax Transmission-Blocking Vaccine Using Pvs25 Transgenic Plasmodium berghei. J Infect Dis 2024; 229:1894-1903. [PMID: 38408353 PMCID: PMC11175679 DOI: 10.1093/infdis/jiae102] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2023] [Revised: 01/20/2024] [Accepted: 02/22/2024] [Indexed: 02/28/2024] Open
Abstract
BACKGROUND Plasmodium falciparum and Plasmodium vivax account for >90% global malaria burden. Transmission intervention strategies encompassing transmission-blocking vaccines (TBV) and drugs represent ideal public health tools to eliminate malaria at the population level. The availability of mature P. falciparum gametocytes through in vitro culture has facilitated development of a standard membrane feeding assay to assess efficacy of transmission interventions against P. falciparum. The lack of in vitro culture for P. vivax has significantly hampered similar progress on P. vivax and limited studies have been possible using blood from infected patients in endemic areas. The ethical and logistical limitations of on-time access to blood from patients have impeded the development of P. vivax TBVs. METHODS Transgenic murine malaria parasites (Plasmodium berghei) expressing TBV candidates offer a promising alternative for evaluation of P. vivax TBVs through in vivo studies in mice, and ex vivo membrane feeding assay (MFA). RESULTS We describe the development of transmission-competent transgenic TgPbvs25 parasites and optimization of parameters to establish an ex vivo MFA to evaluate P. vivax TBV based on Pvs25 antigen. CONCLUSIONS The MFA is expected to expedite Pvs25-based TBV development without dependence on blood from P. vivax-infected patients in endemic areas for evaluation.
Collapse
Affiliation(s)
- Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Clifford T H Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, District of Columbia, USA
| |
Collapse
|
3
|
Kisakov DN, Belyakov IM, Kisakova LA, Yakovlev VA, Tigeeva EV, Karpenko LI. The use of electroporation to deliver DNA-based vaccines. Expert Rev Vaccines 2024; 23:102-123. [PMID: 38063059 DOI: 10.1080/14760584.2023.2292772] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2023] [Accepted: 12/05/2023] [Indexed: 12/19/2023]
Abstract
INTRODUCTION Nucleic acids represent a promising platform for creating vaccines. One disadvantage of this approach is its relatively low immunogenicity. Electroporation (EP) is an effective way to increase the DNA vaccines immunogenicity. However, due to the different configurations of devices used for EP, EP protocols optimization is required not only to enhance immunogenicity, but also to ensure greater safety and tolerability of the EP procedure. AREA COVERED An data analysis for recent years on the DNA vaccines delivery against viral and parasitic infections using EP was carried out. The study of various EP physical characteristics, such as frequency, pulse duration, pulse interval, should be considered along with the immunogenic construct design and the site of delivery of the vaccine, through the study of the immunogenic and protective characteristics of the latter. EXPERT OPINION Future research should focus on regulating the humoral and cellular response required for protection against infectious agents by modifying the EP protocol. Significant efforts will be directed to establishing the possibility of redirecting the immune response toward the Th1 or Th2 response by changing the EP physical parameters. It will allow for an individual selective approach during EP, depending on the pathogen type of an infectious disease.
Collapse
Affiliation(s)
- Denis N Kisakov
- Department of bioengineering, State Research Center of Virology and Biotechnology VECTOR, Rospotrebnadzor, Novosibirsk region, Russia
| | - Igor M Belyakov
- Department of medico-biological disciplines, Moscow University for Industry and Finance "Synergy", Moscow, Russia
| | - Lubov A Kisakova
- Department of bioengineering, State Research Center of Virology and Biotechnology VECTOR, Rospotrebnadzor, Novosibirsk region, Russia
| | - Vladimir A Yakovlev
- Department of bioengineering, State Research Center of Virology and Biotechnology VECTOR, Rospotrebnadzor, Novosibirsk region, Russia
| | - Elena V Tigeeva
- Department of bioengineering, State Research Center of Virology and Biotechnology VECTOR, Rospotrebnadzor, Novosibirsk region, Russia
| | - Larisa I Karpenko
- Department of bioengineering, State Research Center of Virology and Biotechnology VECTOR, Rospotrebnadzor, Novosibirsk region, Russia
| |
Collapse
|
4
|
Bansal GP, Kumar N. Immune mechanisms targeting malaria transmission: opportunities for vaccine development. Expert Rev Vaccines 2024; 23:645-654. [PMID: 38888098 DOI: 10.1080/14760584.2024.2369583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2024] [Accepted: 06/14/2024] [Indexed: 06/20/2024]
Abstract
INTRODUCTION Malaria continues to remain a major global health problem with nearly a quarter of a billion clinical cases and more than 600,000 deaths in 2022. There has been significant progress toward vaccine development, however, poor efficacy of approved vaccines requiring multiple immunizing doses emphasizes the need for continued efforts toward improved vaccines. Progress to date, nonetheless, has provided impetus for malaria elimination. AREAS COVERED In this review we will focus on diverse immune mechanisms targeting gametocytes in the human host and gametocyte-mediated malaria transmission via the mosquito vector. EXPERT OPINION To march toward the goal of malaria elimination it will be critical to target the process of malaria transmission by mosquitoes, mediated exclusively by the sexual stages, i.e. male, and female gametocytes, ingested from infected vertebrate host. Studies over several decades have established antigens in the parasite sexual stages developing in the mosquito midgut as attractive targets for the development of transmission blocking vaccines (TBVs). Immune clearance of gametocytes in the vertebrate host can synergize with TBVs and directly aid in maintaining effective transmission reducing immune potential.
Collapse
Affiliation(s)
- Geetha P Bansal
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, LA, USA
- Fogarty International Center, National Institutes of Health, Bethesda, MD, USA
| | - Nirbhay Kumar
- Department of Global Health, The Milken Institute School of Public Health, George Washington University, Washington, DC, USA
| |
Collapse
|
5
|
Tsoumani ME, Voyiatzaki C, Efstathiou A. Malaria Vaccines: From the Past towards the mRNA Vaccine Era. Vaccines (Basel) 2023; 11:1452. [PMID: 37766129 PMCID: PMC10536368 DOI: 10.3390/vaccines11091452] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2023] [Revised: 08/29/2023] [Accepted: 09/01/2023] [Indexed: 09/29/2023] Open
Abstract
Plasmodium spp. is the etiological agent of malaria, a life-threatening parasitic disease transmitted by infected mosquitoes. Malaria remains a major global health challenge, particularly in endemic regions. Over the years, various vaccine candidates targeting different stages of Plasmodium parasite life-cycle have been explored, including subunit vaccines, vectored vaccines, and whole organism vaccines with Mosquirix, a vaccine based on a recombinant protein, as the only currently approved vaccine for Plasmodium falciparum malaria. Despite the aforementioned notable progress, challenges such as antigenic diversity, limited efficacy, resistant parasites escaping protective immunity and the need for multiple doses have hindered the development of a highly efficacious malaria vaccine. The recent success of mRNA-based vaccines against SARS-CoV-2 has sparked renewed interest in mRNA vaccine platforms. The unique mRNA vaccine features, including their potential for rapid development, scalability, and flexibility in antigen design, make them a promising avenue for malaria vaccine development. This review provides an overview of the malaria vaccines' evolution from the past towards the mRNA vaccine era and highlights their advantages in overcoming the limitations of previous malaria vaccine candidates.
Collapse
Affiliation(s)
- Maria E. Tsoumani
- Department of Biomedical Sciences, University of West Attica, 12243 Aigaleo, Greece; (M.E.T.); (C.V.)
| | - Chrysa Voyiatzaki
- Department of Biomedical Sciences, University of West Attica, 12243 Aigaleo, Greece; (M.E.T.); (C.V.)
| | - Antonia Efstathiou
- Department of Biomedical Sciences, University of West Attica, 12243 Aigaleo, Greece; (M.E.T.); (C.V.)
- Immunology of Infection Group, Department of Microbiology, Hellenic Pasteur Institute, 11521 Athens, Greece
| |
Collapse
|
6
|
Waghela IN, Mallory KL, Taylor JA, Schneider CG, Savransky T, Janse CJ, Lin PJC, Tam YK, Weissman D, Angov E. Exploring in vitro expression and immune potency in mice using mRNA encoding the Plasmodium falciparum malaria antigen, CelTOS. Front Immunol 2022; 13:1026052. [PMID: 36591298 PMCID: PMC9798330 DOI: 10.3389/fimmu.2022.1026052] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Accepted: 11/18/2022] [Indexed: 12/23/2022] Open
Abstract
The secreted malarial protein, Cell-Traversal protein for Ookinetes and Sporozoites (CelTOS), is highly conserved among Plasmodium species, and plays a role in the invasion of mosquito midgut cells and hepatocytes in the vertebrate host. CelTOS was identified as a potential protective antigen based on a proteomic analysis, which showed that CelTOS stimulated significant effector T cells producing IFN-γ in peripheral blood mononuclear cells (PBMCs) from radiation attenuated sporozoite-immunized, malaria-naïve human subjects. In a rodent malaria model, recombinant full-length CelTOS protein/adjuvant combinations induced sterile protection, and in several studies, functional antibodies were produced that had hepatocyte invasion inhibition and transmission-blocking activities. Despite some encouraging results, vaccine approaches using CelTOS will require improvement before it can be considered as an effective vaccine candidate. Here, we report on the use of mRNA vaccine technology to induce humoral and cell-mediated immune responses using this antigen. Several pfceltos encoding mRNA transcripts were assessed for the impact on protein translation levels in vitro. Protein coding sequences included those to evaluate the effects of signal sequence, N-glycosylation on translation, and of nucleoside substitutions. Using in vitro transfection experiments as a pre-screen, we assessed the quality of the expressed CelTOS target relative to the homogeneity, cellular localization, and durability of expression levels. Optimized mRNA transcripts, which demonstrated highest protein expression levels in vitro were selected for encapsulation in lipid nanoparticles (LNP) and used to immunize mice to assess for both humoral and cellular cytokine responses. Our findings indicate that mRNA transcripts encoding pfceltos while potent for inducing antigen-specific cellular cytokine responses in mice, were less able to mount PfCelTOS-specific antibody responses using a two-dose regimen. An additional booster dose was needed to overcome low seroconversion rates in mice. With respect to antibody fine specificities, N-glycosylation site mutated immunogens yielded lower immune responses, particularly to the N-terminus of the molecule. While it remains unclear the impact on CelTOS antigen as immunogen, this study highlights the need to optimize antigen design for vaccine development.
Collapse
Affiliation(s)
- Ishita N. Waghela
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,Parsons Corporation, Centreville, VA, United States
| | - Katherine L. Mallory
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,Parsons Corporation, Centreville, VA, United States
| | - Justin A. Taylor
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,The Geneva Foundation, Tacoma, WA, United States
| | - Cosette G. Schneider
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,Oak Ridge Institute for Science and Education, Oak Ridge, TN, United States
| | - Tatyana Savransky
- Entomology Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,General Dynamics Information Technology, Falls Church, VA, United States
| | - Chris J. Janse
- Parasitology, Center of Infectious Diseases, Leiden University Medical Center, Leiden, Netherlands
| | | | - Ying K. Tam
- Acuitas Therapeutics Inc., Vancouver, BC, Canada
| | - Drew Weissman
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Evelina Angov
- Malaria Biologics Branch, Walter Reed Army Institute of Research, Silver Spring, MD, United States,*Correspondence: Evelina Angov,
| |
Collapse
|
7
|
Hayashi CTH, Cao Y, Clark LC, Tripathi AK, Zavala F, Dwivedi G, Knox J, Alameh MG, Lin PJC, Tam YK, Weissman D, Kumar N. mRNA-LNP expressing PfCSP and Pfs25 vaccine candidates targeting infection and transmission of Plasmodium falciparum. NPJ Vaccines 2022; 7:155. [PMID: 36456563 PMCID: PMC9715627 DOI: 10.1038/s41541-022-00577-8] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 11/03/2022] [Indexed: 12/03/2022] Open
Abstract
Malaria is a deadly disease responsible for between 550,000 and 627,000 deaths annually. There is a pressing need to develop vaccines focused on malaria elimination. The complex lifecycle of Plasmodium falciparum provides opportunities not only to target the infectious sporozoite stage, introduced by anopheline mosquitoes, but also the sexual stages, which are ingested by mosquitoes during blood feeding, leading to parasite transmission. It is widely recognized that a vaccine targeting multiple stages would induce efficacious transmission reducing immunity. Technological advancements offer new vaccine platforms, such as mRNA-LNPs, which can be used to develop highly effective malarial vaccines. We evaluated the immunogenicity of two leading P. falciparum vaccine candidates, Pfs25 and PfCSP, delivered as mRNA-LNP vaccines. Both vaccines induced extremely potent immune responses when administered alone or in combination, which were superior to Pfs25 and PfCSP DNA vaccine formulations. Purified IgGs from Pfs25 mRNA-LNPs immunized mice were highly potent in reducing malaria transmission to mosquitoes. Additionally, mice after three and four immunizations with PfCSP mRNA-LNP provided evidence for varying degrees of protection against sporozoite challenge. The comparison of immune responses and stage-specific functional activity induced by each mRNA-LNP vaccine, administered alone or in combination, also supports the development of an effective combination vaccine without any risk of immune interference for targeting malaria parasites at various life cycle stages. A combination of vaccines targeting both the infective stage and sexual/midgut stages is expected to interrupt malaria transmission, which is critical for achieving elimination goals.
Collapse
Affiliation(s)
- Clifford T H Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Leor C Clark
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA
| | - Abhai K Tripathi
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21215, USA
| | - Fidel Zavala
- Johns Hopkins Malaria Research Institute, Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD, 21215, USA
| | - Garima Dwivedi
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - James Knox
- Department of Pathology, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | | | | | - Ying K Tam
- Acuitas Therapeutics, Vancouver, BC, Canada
| | - Drew Weissman
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, 19104, USA
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC, 20052, USA.
| |
Collapse
|
8
|
Cao Y, Hayashi CTH, Zavala F, Tripathi AK, Simonyan H, Young CN, Clark LC, Usuda Y, Van Parys JM, Kumar N. Effective Functional Immunogenicity of a DNA Vaccine Combination Delivered via In Vivo Electroporation Targeting Malaria Infection and Transmission. Vaccines (Basel) 2022; 10:1134. [PMID: 35891298 PMCID: PMC9323668 DOI: 10.3390/vaccines10071134] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 07/13/2022] [Accepted: 07/14/2022] [Indexed: 11/16/2022] Open
Abstract
Plasmodium falciparum circumsporozoite protein (PfCSP) and Pfs25 are leading candidates for the development of pre-erythrocytic and transmission-blocking vaccines (TBV), respectively. Although considerable progress has been made in developing PfCSP- and Pfs25-based vaccines, neither have elicited complete protection or transmission blocking in clinical trials. The combination of antigens targeting various life stages is an alternative strategy to develop a more efficacious malaria vaccine. In this study, female and male mice were immunized with DNA plasmids encoding PfCSP and Pfs25, administered alone or in combination via intramuscular in vivo electroporation (EP). Antigen-specific antibodies were analyzed for antibody titers, avidity and isotype by ELISA. Immune protection against sporozoite challenge, using transgenic P. berghei expressing PfCSP and a GFP-luciferase fusion protein (PbPfCSP-GFP/Luc), was assessed by in vivo bioluminescence imaging and blood-stage parasite growth. Transmission reducing activity (TRA) was evaluated in standard membrane feeding assays (SMFA). High levels of PfCSP- and Pfs25-specific antibodies were induced in mice immunized with either DNA vaccine alone or in combination. No difference in antibody titer and avidity was observed for both PfCSP and Pfs25 between the single DNA and combined DNA immunization groups. When challenged by PbPfCSP-GFP/Luc sporozoites, mice immunized with PfCSP alone or combined with Pfs25 revealed significantly reduced liver-stage parasite loads as compared to mice immunized with Pfs25, used as a control. Furthermore, parasite liver loads were negatively correlated with PfCSP-specific antibody levels. When evaluating TRA, we found that immunization with Pfs25 alone or in combination with PfCSP elicited comparable significant transmission reduction. Our studies reveal that the combination of PfCSP and Pfs25 DNAs into a vaccine delivered by in vivo EP in mice does not compromise immunogenicity, infection protection and transmission reduction when compared to each DNA vaccine individually, and provide support for further evaluation of this DNA combination vaccine approach in larger animals and clinical trials.
Collapse
Affiliation(s)
- Yi Cao
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| | - Clifford T. H. Hayashi
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| | - Fidel Zavala
- Department of Molecular Microbiology & Immunology, Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA; (F.Z.); (A.K.T.)
| | - Abhai K. Tripathi
- Department of Molecular Microbiology & Immunology, Johns Hopkins Malaria Research Institute, Bloomberg School of Public Health, Johns Hopkins University, Baltimore, MD 21205, USA; (F.Z.); (A.K.T.)
| | - Hayk Simonyan
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, Washington, DC 20052, USA; (H.S.); (C.N.Y.)
| | - Colin N. Young
- Department of Pharmacology and Physiology, School of Medicine and Health Sciences, George Washington University, Washington, DC 20052, USA; (H.S.); (C.N.Y.)
| | - Leor C. Clark
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| | - Yukari Usuda
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| | - Jacob M. Van Parys
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| | - Nirbhay Kumar
- Department of Global Health, Milken Institute School of Public Health, George Washington University, Washington, DC 20052, USA; (Y.C.); (C.T.H.H.); (L.C.C.); (Y.U.); (J.M.V.P.)
| |
Collapse
|
9
|
Design and assessment of TRAP-CSP fusion antigens as effective malaria vaccines. PLoS One 2020; 15:e0216260. [PMID: 31967991 PMCID: PMC6975556 DOI: 10.1371/journal.pone.0216260] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 12/16/2019] [Indexed: 11/25/2022] Open
Abstract
The circumsporozoite protein (CSP) and thrombospondin-related adhesion protein (TRAP) are major targets for pre-erythrocytic malaria vaccine development. However, the CSP-based vaccine RTS,S provides only marginal protection, highlighting the need for innovative vaccine design and development. Here we design and characterize expression and folding of P. berghei (Pb) and P. falciparum (Pf) TRAP-CSP fusion proteins, and evaluate immunogenicity and sterilizing immunity in mice. TRAP N-terminal domains were fused to the CSP C-terminal αTSR domain with or without the CSP repeat region, expressed in mammalian cells, and evaluated with or without N-glycan shaving. Pb and Pf fusions were each expressed substantially better than the TRAP or CSP components alone; furthermore, the fusions but not the CSP component could be purified to homogeneity and were well folded and monomeric. As yields of TRAP and CSP fragments were insufficient, we immunized BALB/c mice with Pb TRAP-CSP fusions in AddaVax adjuvant and tested the effects of absence or presence of the CSP repeats and absence or presence of high mannose N-glycans on total antibody titer and protection from infection by mosquito bite both 2.5 months and 6 months after the last immunization. Fusions containing the repeats were completely protective against challenge and re-challenge, while those lacking repeats were significantly less effective. These results correlated with higher total antibody titers when repeats were present. Our results show that TRAP-CSP fusions increase protein antigen production, have the potential to yield effective vaccines, and also guide design of effective proteins that can be encoded by nucleic acid-based and virally vectored vaccines.
Collapse
|
10
|
Comparative functional potency of DNA vaccines encoding Plasmodium falciparum transmission blocking target antigens Pfs48/45 and Pfs25 administered alone or in combination by in vivo electroporation in rhesus macaques. Vaccine 2017; 35:7049-7056. [PMID: 29132995 DOI: 10.1016/j.vaccine.2017.10.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 09/26/2017] [Accepted: 10/13/2017] [Indexed: 02/07/2023]
Abstract
Antibodies recognizing conformational epitopes in Pfs48/45, an antigen expressed on the surface of Plasmodium falciparum gametes and zygotes, have firmly established Pfs48/45 as a promising transmission blocking vaccine (TBV) candidate. However, it has been difficult to reproducibly express Pfs48/45 in a variety of recombinant expression systems. The goal of our studies was to evaluate functional immunogenicity of Pfs48/45 using DNA vaccine format in rhesus macaques. An additional goal was to ensure that when used in combination with another malarial antigen, specific immunity to both antigens was not compromised. For testing combination vaccines, we employed Pfs25 DNA plasmids that have previously undergone evaluations in rodents and nonhuman primates. Pfs25 is expressed on the surface of parasites after fertilization and is also a lead TBV candidate. DNA plasmids based on codon-optimized sequences of Pfs48/45 and Pfs25 were administered by in vivo electroporation, followed by a final recombinant protein boost. Our studies demonstrate that Pfs48/45 encoded by DNA plasmids is capable of inducing potent transmission blocking antibody responses, and such transmission blocking immune potency of Pfs48/45 was not compromised when tested in combination with Pfs25, These findings provide the evidence in favor of further studies on Pfs48/45 and Pfs25, either alone or in combination with other known malaria vaccine candidates for developing effective vaccines capable of interrupting malaria transmission.
Collapse
|
11
|
Heidari Z, Arora JS, Datta D, John VT, Kumar N, Bansal GP. Impact of the Charge Ratio on the In Vivo Immunogenicity of Lipoplexes. Pharm Res 2017; 34:1796-1804. [PMID: 28560696 PMCID: PMC10601992 DOI: 10.1007/s11095-017-2187-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2016] [Accepted: 05/22/2017] [Indexed: 01/18/2023]
Abstract
PURPOSE The present study investigated the immunogenic potential of different cationic liposome formulations with a DNA plasmid encoding Pfs25, a malaria transmission-blocking vaccine candidate. METHODS Pfs25 plasmid DNA was complexed with cationic liposomes to produce lipoplexes at different charge ratios of the cationic lipid head group to the nucleotide phosphate (N:P). The formation of lipoplexes was visualized by Cryogenic-TEM. Confocal microscopy of lipoplexes formed with GFP encoding plasmid DNA, and flow cytometry was used to determine their in vitro transfection capability. Two different lipoplex formulations using plasmid DNA encoding Pfs25 were evaluated for in vivo immunogenicity after intramuscular administration in Balb/c mice. Immune sera were analyzed by ELISA. RESULTS The results demonstrated that the cationic liposome-mediated DNA immunization with an N:P charge ratio of 1:3 (anionic lipoplexes) is more effective than the use of naked plasmid DNA alone. No antibody response was observed when lipoplexes with a higher N:P charge ratio of 10:3 (cationic lipoplexes) were used. Trehalose was added to some lipoplex formulations as a cryoprotectant and adjuvant, but it did not yield any further improvement of immunogenicity in vivo. CONCLUSIONS The results suggest that Pfs25 plasmid DNA delivered as lipoplexes at a charge ratio of 1:3 elicited strong immunogenicity in mice and may be improved further to match the immune responses of DNA vaccines administered by in vivo electroporation.
Collapse
Affiliation(s)
- Zahra Heidari
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Jaspreet S Arora
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA
- Department of Chemical and Biomolecular Engineering, School of Science and Engineering, Tulane University, New Orleans, Louisiana, USA
| | - Dibyadyuti Datta
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Vijay T John
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA
- Department of Chemical and Biomolecular Engineering, School of Science and Engineering, Tulane University, New Orleans, Louisiana, USA
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA
| | - Geetha P Bansal
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana, USA.
- Vector-Borne Infectious Diseases Research Center, Tulane University, New Orleans, Louisiana, USA.
| |
Collapse
|
12
|
Datta D, Bansal GP, Gerloff DL, Ellefsen B, Hannaman D, Kumar N. Immunogenicity and malaria transmission reducing potency of Pfs48/45 and Pfs25 encoded by DNA vaccines administered by intramuscular electroporation. Vaccine 2017; 35:264-272. [PMID: 27912985 PMCID: PMC5192010 DOI: 10.1016/j.vaccine.2016.11.072] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2016] [Revised: 11/03/2016] [Accepted: 11/22/2016] [Indexed: 01/06/2023]
Abstract
Pfs48/45 and Pfs25 are leading candidates for the development of Plasmodium falciparum transmission blocking vaccines (TBV). Expression of Pfs48/45 in the erythrocytic sexual stages and presentation to the immune system during infection in the human host also makes it ideal for natural boosting. However, it has been challenging to produce a fully folded, functionally active Pfs48/45, using various protein expression platforms. In this study, we demonstrate that full-length Pfs48/45 encoded by DNA plasmids is able to induce significant transmission reducing immune responses. DNA plasmids encoding Pfs48/45 based on native (WT), codon optimized (SYN), or codon optimized and mutated (MUT1 and MUT2), to prevent any asparagine (N)-linked glycosylation were compared with or without intramuscular electroporation (EP). EP significantly enhanced antibody titers and transmission blocking activity elicited by immunization with SYN Pfs48/45 DNA vaccine. Mosquito membrane feeding assays also revealed improved functional immunogenicity of SYN Pfs48/45 (N-glycosylation sites intact) as compared to MUT1 or MUT2 Pfs48/45 DNA plasmids (all N-glycosylation sites mutated). Boosting with recombinant Pfs48/45 protein after immunization with each of the different DNA vaccines resulted in significant boosting of antibody response and improved transmission reducing capabilities of all four DNA vaccines. Finally, immunization with a combination of DNA plasmids (SYN Pfs48/45 and SYN Pfs25) also provides support for the possibility of combining antigens targeting different life cycle stages in the parasite during transmission through mosquitoes.
Collapse
Affiliation(s)
- Dibyadyuti Datta
- Department of Tropical Medicine, School of Public Health and Tropical Medicine and Vector-Borne Infectious Disease Research Center, Tulane University, New Orleans, LA, United States
| | - Geetha P Bansal
- Department of Tropical Medicine, School of Public Health and Tropical Medicine and Vector-Borne Infectious Disease Research Center, Tulane University, New Orleans, LA, United States
| | | | - Barry Ellefsen
- ICHOR Medical Systems Inc., San Diego, CA, United States
| | - Drew Hannaman
- ICHOR Medical Systems Inc., San Diego, CA, United States
| | - Nirbhay Kumar
- Department of Tropical Medicine, School of Public Health and Tropical Medicine and Vector-Borne Infectious Disease Research Center, Tulane University, New Orleans, LA, United States.
| |
Collapse
|
13
|
Lee SM, Wu CK, Plieskatt J, McAdams DH, Miura K, Ockenhouse C, King CR. Assessment of Pfs25 expressed from multiple soluble expression platforms for use as transmission-blocking vaccine candidates. Malar J 2016; 15:405. [PMID: 27515826 PMCID: PMC4982271 DOI: 10.1186/s12936-016-1464-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2016] [Accepted: 07/29/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Transmission-blocking vaccines (TBVs) have become a focus of strategies to control and eventually eliminate malaria as they target the entry of sexual stage into the Anopheles stephensi mosquito thereby preventing transmission, an essential component of the parasite life cycle. Such vaccines are envisioned as complements to vaccines that target human infection, such as RTS,S as well as drug treatment, and vector control strategies. A number of conserved proteins, including Pfs25, have been identified as promising TBV targets in research or early stage development. Pfs25 is a 25 kDa protein of Plasmodium falciparum expressed on the surface of zygotes and ookinetes. Its complex tertiary structure, including numerous cysteines, has led to difficulties in the expression of a recombinant protein that is homogeneous, with proper conformation, and free of glycosylation, a phenomenon not found in native parasite machinery. METHODS While the expression and purification of Pfs25 in various systems, has been previously independently reported, here a parallel analysis of Pfs25 is presented to inform on the biochemical features of Pfs25 and their impact on functionality. Three scalable expression systems were used to express, purify, and evaluate Pfs25 both in vitro and in vivo, including the ability of each protein to produce functional antibodies through the standard membrane feeding assay. RESULTS Through numerous attempts, soluble, monomeric Pfs25 derived from Escherichia coli was not achieved, while Pichia pastoris presented Pfs25 as an inhomogeneous product with glycosylation. In comparison, baculovirus produced a pure, monomeric protein free of glycosylation. The glycosylation present for Pichia produced Pfs25, showed no notable decrease in the ability to elicit transmission reducing antibodies in functional evaluation, while a reduced and alkylated Pfs25 (derived from plant and used as a control) was found to have significantly decreased transmission reducing activity, emphasizing the importance of ensuring correct disulfide stabilized conformation during vaccine design and production. CONCLUSIONS In this study, the biochemical features of Pfs25, produced from different expression systems, are described along with their impact on the ability of the protein to elicit functional antibodies. Pfs25 expressed using baculovirus and Pichia showed promise as candidates for vaccine development.
Collapse
Affiliation(s)
- Shwu-Maan Lee
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001-2621, USA.
| | - Chia-Kuei Wu
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001-2621, USA
| | - Jordan Plieskatt
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001-2621, USA
| | - David H McAdams
- PATH, 2201 Westlake Avenue, Suite 200, Seattle, WA, 98121, USA
| | - Kazutoyo Miura
- Laboratory of Malaria and Vector Research, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, 20852, USA
| | - Chris Ockenhouse
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001-2621, USA
| | - C Richter King
- PATH Malaria Vaccine Initiative (MVI), 455 Massachusetts Avenue NW, Suite 1000, Washington, DC, 20001-2621, USA
| |
Collapse
|
14
|
Du F, Wang S, Zhao C, Cao YM, Luo EJ. Immunogenicity and immunizing protection effect of GAMA gene DNA vaccine on Plasmodium berghei. ASIAN PAC J TROP MED 2016; 9:158-63. [PMID: 26919947 DOI: 10.1016/j.apjtm.2016.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 12/20/2015] [Accepted: 12/30/2015] [Indexed: 10/22/2022] Open
Abstract
OBJECTIVE To explore the effect of immunogenicity and immunizing protection of GAMA gene DNA vaccine, which was related with merozoite, ookinete and sporozoite invasion. METHODS Gene fragments were obtained using PCR technique and eukaryotic expression vector (containing immunostimulatory sequence) was built. BALB/c mice were divided into PBS control group, empty vector control group and study group and were immunized at week 0, 3 and 6 respectively. Blood was collected 2 weeks after each immunization and serum was separated to detect the IgG, IgG1 and IgG2a levels. Spleen of mice was obtained for preparation of splenic mononuclear cell and the cytokine IL-4 and IFN-γ levels were detected. Indirect immunofluorescence and western blot were employed to verify the specificity of antiserum. Sporozoite and merozoite invasion were used respectively to detect the immune protective effect 2 weeks after the third immunization. Ookinete conversion rate in vitro and oocyst numbers of mosquito stomach were observed to evaluate the transmission-blocking levels. RESULTS In GAMA DNA vaccine group: antiserum could be combined with recombinant protein specifically and green fluorescence signals of merozoite, ookinete and sporozoite were observable, while specific fragments and fluorescence signals were not observable in empty vector group. Compared with control group, specific IgG in DNA vaccine immunity group significantly increased (P < 0.01), and IgG1 and IgG2a all increased (P < 0.01). IL-4, IFN-γ content in study group significantly increased, compared with control group (P < 0.01). GAMA DNA vaccine immunity could not obviously block the erythrocyte-stage infection (caused by sporozoite invasion); compared with control group, liver worm load was slightly reduced (P < 0.05), and antiserum ookinete numbers (cultured in vitro) had no significant difference with oocyst numbers of mosquito stomach in DNA vaccine group. CONCLUSIONS GAMA has good antigenicity, which could stimulate the body to produce specific immune responses; while DNA vaccine immunity could not play a good protective effect, the effect of which is only limited to the slight reduction of liver worm load, and has no obvious erythrocyte-stage protective effect and transmission-blocking effect. Therefore, trying other immunization strategies for further research on the value of GAMA (as multi-stage antigen vaccine and multi-stage combined vaccine components of the life-cycle of plasmodium) is necessary.
Collapse
Affiliation(s)
- Feng Du
- Department of Pathogen Biology, Basic Medical College of China Medical University, Shenyang City, Liaoning, China
| | - Si Wang
- Department of Pathogen Biology, Basic Medical College of China Medical University, Shenyang City, Liaoning, China
| | - Chen Zhao
- Inspection Institute of Jilin Medical College, China
| | - Ya-Ming Cao
- Department of Immunology, Basic Medical College of China Medical University, Shenyang City, Liaoning, China
| | - En-Jie Luo
- Department of Pathogen Biology, Basic Medical College of China Medical University, Shenyang City, Liaoning, China.
| |
Collapse
|