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Rajneesh, Tiwari R, Singh VK, Kumar A, Gupta RP, Singh AK, Gautam V, Kumar R. Advancements and Challenges in Developing Malaria Vaccines: Targeting Multiple Stages of the Parasite Life Cycle. ACS Infect Dis 2023; 9:1795-1814. [PMID: 37708228 DOI: 10.1021/acsinfecdis.3c00332] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/16/2023]
Abstract
Malaria, caused by Plasmodium species, remains a major global health concern, causing millions of deaths annually. While the introduction of the RTS,S vaccine has shown promise, there is a pressing need for more effective vaccines due to the emergence of drug-resistant parasites and insecticide-resistant vectors. However, the complex life cycle and genetic diversity of the parasite, technical obstacles, limited funding, and the impact of the 2019 pandemic have hindered progress in malaria vaccine development. This review focuses on advancements in malaria vaccine development, particularly the ongoing clinical trials targeting antigens from different stages of the Plasmodium life cycle. Additionally, we discuss the rationale, strategies, and challenges associated with vaccine design, aiming to enhance the immune response and protective efficacy of vaccine candidates. A cost-effective and multistage vaccine could hold the key to controlling and eradicating malaria.
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Affiliation(s)
- Rajneesh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rahul Tiwari
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Vishal K Singh
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Awnish Kumar
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rohit P Gupta
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
- Department of Applied Microbiology, Institute of Science, Banaras Hindu University, Varanasi 221005, India
| | - Akhilesh K Singh
- Faculty of Dental Science, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Vibhav Gautam
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
| | - Rajiv Kumar
- Centre of Experimental Medicine & Surgery, Institute of Medical Sciences, Banaras Hindu University, Varanasi 221005, India
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Ibraheem Y, Bayarsaikhan G, Inoue SI. Host immunity to Plasmodium infection: Contribution of Plasmodium berghei to our understanding of T cell-related immune response to blood-stage malaria. Parasitol Int 2022; 92:102646. [PMID: 35998816 DOI: 10.1016/j.parint.2022.102646] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Revised: 08/09/2022] [Accepted: 08/12/2022] [Indexed: 10/15/2022]
Abstract
Malaria is a life-threatening disease caused by infection with Plasmodium parasites. The goal of developing an effective malaria vaccine is yet to be reached despite decades of massive research efforts. CD4+ helper T cells, CD8+ cytotoxic T cells, and γδ T cells are associated with immune responses to both liver-stage and blood-stage Plasmodium infection. The immune responses of T cell-lineages to Plasmodium infection are associated with both protection and immunopathology. Studies with mouse model of malaria contribute to our understanding of host immune response. In this paper, we focus primarily on mouse malaria model with blood-stage Plasmodium berghei infection and review our knowledge of T cell immune responses against Plasmodium infection. Moreover, we also discuss findings of experimental human studies. Uncovering the precise mechanisms of T cell-mediated immunity to Plasmodium infection can be accomplished through further investigations using mouse models of malaria with rodent Plasmodium parasites. Those findings would be invaluable to advance the efforts for development of an effective malaria vaccine.
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Affiliation(s)
- Yarob Ibraheem
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan
| | - Ganchimeg Bayarsaikhan
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan
| | - Shin-Ichi Inoue
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, 1-12-4 Sakamoto, Nagasaki-city, Nagasaki 852-8523, Japan.
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Moris P, Jongert E, van der Most RG. Characterization of T-cell immune responses in clinical trials of the candidate RTS,S malaria vaccine. Hum Vaccin Immunother 2017; 14:17-27. [PMID: 28934066 PMCID: PMC5791571 DOI: 10.1080/21645515.2017.1381809] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The candidate malaria vaccine RTS,S has demonstrated 45.7% efficacy over 18 months against all clinical disease in a phase-III field study of African children. RTS,S targets the circumsporozoite protein (CSP), which is expressed on the Plasmodium sporozoite during the pre-erythrocyte stage of its life-cycle; the stage between mosquito bite and liver infection. Early in the development of RTS,S, it was recognized that CSP-specific cell-mediated immunity (CMI) was required to complement CSP-specific antibody-mediated immunity. In reviewing RTS,S clinical studies, associations between protection and various types of CMI (CSP-specific CD4+ T cells and INF-γ ELISPOTs) have been identified, but not consistently. It is plausible that certain CD4+ T cells support antibody responses or co-operate with other immune-cell types to potentially elicit protection. However, the identities of vaccine correlates of protection, implicating either CSP-specific antibodies or T cells remain elusive, suggesting that RTS,S clinical trials may benefit from additional immunogenicity analyses that can be informed by the results of controlled human malaria infection studies.
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Sacci JB, Hollingdale MR, Sedegah M. Cellular immune response to DNA and vaccinia prime-boost immunization kills Plasmodium yoelii-infected hepatocytes in vitro. Pathog Dis 2017; 75:3798571. [PMID: 28475711 DOI: 10.1093/femspd/ftx051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 05/03/2017] [Indexed: 11/13/2022] Open
Abstract
Background Plasmid DNA encoding Plasmodium yoelii circumsporozoite protein (PyCSP) followed by boosting with recombinant vaccinia virus containing the PyCSP elicited significant protective immunity in mice that was primarily mediated by CD8+ T-cell responses directed to P. yoelii -infected hepatocytes. This study was to further explore protection using in vitro cultures of P. yoelii parasites in mouse hepatocytes. Spleen cells from DNA/vaccinia virus-immunized mice were co-cultured in vitro with mouse hepatocytes containing developing P. yoelii liver stage parasites. A semipermeable membrane separating spleen cells and hepatocytes was used to demonstrate if cell-to-cell contact was required. Inhibitors of mediators likely involved in spleen cell killing were added to these co-cultures. Spleen cells from immunized mice inhibited in vitro P. yoelii parasite development, and inhibition was eliminated by separating effectors and targets with the semipermeable membrane. Additionally, inhibitors of inducible nitric oxide synthase, caspase activation, NF-κB activation as well as antibodies against interferon-gamma (IFN-γ) and ICAM-1 reduced parasite inhibition. These findings suggest that direct contact between spleen cells from immunized mice and P. yoelii-infected hepatocytes is required for eliminating liver stage parasites and provide more insight into CD8+ T-cell-mediated inhibition of malaria liver stage development.
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Affiliation(s)
- John B Sacci
- Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD 21201, USA
| | | | - Martha Sedegah
- Malaria Program, Naval Medical Research Center, Silver Spring, MD 20910, USA
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Protective immunity to liver-stage malaria. Clin Transl Immunology 2016; 5:e105. [PMID: 27867517 PMCID: PMC5099428 DOI: 10.1038/cti.2016.60] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 09/14/2016] [Accepted: 09/14/2016] [Indexed: 12/15/2022] Open
Abstract
Despite decades of research and recent clinical trials, an efficacious long-lasting preventative vaccine for malaria remains elusive. This parasite infects mammals via mosquito bites, progressing through several stages including the relatively short asymptomatic liver stage followed by the more persistent cyclic blood stage, the latter of which is responsible for all disease symptoms. As the liver acts as a bottleneck to blood-stage infection, it represents a potential site for parasite and disease control. In this review, we discuss immunity to liver-stage malaria. It is hoped that the knowledge gained from animal models of malaria immunity will translate into a more powerful and effective vaccine to reduce this global health problem.
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Akbari M, Kimura K, Houts JT, Yui K. Intravital imaging of the immune responses during liver-stage malaria infection: An improved approach for fixing the liver. Parasitol Int 2016; 65:502-505. [PMID: 26921520 DOI: 10.1016/j.parint.2016.02.011] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 02/10/2016] [Accepted: 02/23/2016] [Indexed: 11/26/2022]
Abstract
The host-parasite relationship is one of the main themes of modern parasitology. Recent revolutions in science, including the development of various fluorescent proteins/probes and two-photon microscopy, have made it possible to directly visualize and study the mechanisms underlying the interaction between the host and pathogen. Here, we describe our method of preparing and setting-up the liver for our experimental approach of using intravital imaging to examine the interaction between Plasmodium berghei ANKA and antigen-specific CD8+ T cells during the liver-stage of the infection in four dimensions. Since the liver is positioned near the diaphragm, neutralization of respiratory movements is critical during the imaging process. In addition, blood circulation and temperature can be affected by the surgical exposure due to the anatomy and tissue structure of the liver. To control respiration, we recommend anesthesia with isoflurane inhalation at 1% during the surgery. In addition, our protocol introduces a cushion of gauze around the liver to avoid external pressure on the liver during intravital imaging using an inverted microscope, which makes it possible to image the liver tissue for long periods with minimal reduction in the blood circulation and with minimal displacement and tissue damage. The key point of this method is to reduce respiratory movements and external pressure on the liver tissue during intravital imaging.
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Affiliation(s)
- Masoud Akbari
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan.
| | - Kazumi Kimura
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan.
| | - James T Houts
- Patterson Scientific, 1160 Chess Drive Suite #9, Foster City, CA 94404, USA.
| | - Katsuyuki Yui
- Division of Immunology, Department of Molecular Microbiology and Immunology, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8523, Japan.
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Frevert U, Krzych U, Richie TL. Editorial: Breaking the cycle: attacking the malaria parasite in the liver. Front Microbiol 2015; 6:810. [PMID: 26300873 PMCID: PMC4528169 DOI: 10.3389/fmicb.2015.00810] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/22/2015] [Indexed: 01/29/2023] Open
Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine New York, NY, USA
| | - Urszula Krzych
- Cellular Immunology, Walter Reed Army Institute of Research Silver Spring, MD, USA
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Frevert U, Krzych U. Plasmodium cellular effector mechanisms and the hepatic microenvironment. Front Microbiol 2015; 6:482. [PMID: 26074888 PMCID: PMC4445044 DOI: 10.3389/fmicb.2015.00482] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Accepted: 05/01/2015] [Indexed: 12/23/2022] Open
Abstract
Plasmodium falciparum malaria remains one of the most serious health problems globally. Immunization with attenuated parasites elicits multiple cellular effector mechanisms capable of eliminating Plasmodium liver stages. However, malaria liver stage (LS) immunity is complex and the mechanisms effector T cells use to locate the few infected hepatocytes in the large liver in order to kill the intracellular LS parasites remain a mystery to date. Here, we review our current knowledge on the behavior of CD8 effector T cells in the hepatic microvasculature, in malaria and other hepatic infections. Taking into account the unique immunological and lymphogenic properties of the liver, we discuss whether classical granule-mediated cytotoxicity might eliminate infected hepatocytes via direct cell contact or whether cytokines might operate without cell–cell contact and kill Plasmodium LSs at a distance. A thorough understanding of the cellular effector mechanisms that lead to parasite death hence sterile protection is a prerequisite for the development of a successful malaria vaccine to protect the 40% of the world’s population currently at risk of Plasmodium infection.
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Affiliation(s)
- Ute Frevert
- Division of Medical Parasitology, Department of Microbiology, New York University School of Medicine , New York, NY, USA
| | - Urszula Krzych
- Division of Malaria Vaccine Development, Department of Cellular Immunology, Walter Reed Army Institute of Research , Silver Spring, MD, USA
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