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Moseman AP, Chen CW, Liang X, Liao D, Kuraoka M, Moseman EA. Therapeutic glycan-specific antibody binding mediates protection during primary amoebic meningoencephalitis. Infect Immun 2024:e0018324. [PMID: 39235225 DOI: 10.1128/iai.00183-24] [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: 04/22/2024] [Accepted: 07/24/2024] [Indexed: 09/06/2024] Open
Abstract
Naegleria fowleri (N. fowleri) infection via the upper respiratory tract causes a fatal CNS disease known as primary amoebic meningoencephalitis (PAM). The robust in vivo immune response to N. fowleri infection underlies the immunopathology that characterizes the disease. However, little is known about why this pathogen evades immune control. Infections occur in seemingly healthy individuals and effective clinical options are lacking, thus a nearly 98% fatality rate. It is unclear how or if host factors may contribute to susceptibility or disease exacerbation, yet mechanistic studies of the in vivo immune response and disease progression are hampered by a lack of tools. In this study, we have generated monoclonal antibodies to N. fowleri surface antigens and shown them to be excellent tools for studying the in vivo immune response. We also identified one monoclonal, 2B6, with potent inherent anti-amoebastatic activity in vitro. This antibody is also able to therapeutically prolong host survival in vivo and furthermore, recombinant antibodies with an isotype more capable of directing immune effector activity further improved survival when given therapeutically. Thus, we report the generation of a novel monoclonal antibody to N. fowleri that can enhance beneficial immune functions, even when given therapeutically during disease. We believe this provides evidence for the potential of therapeutic antibody treatments in PAM.IMPORTANCENaegleria fowleri (N. fowleri) is a free-living amoeba that is found ubiquitously in warm freshwater. While human exposure is common, it rarely results in pathogenesis. However, when N. fowleri gains access to the upper airway, specifically the olfactory mucosa, infection leads to a lethal disease known as primary amoebic meningoencephalitis (PAM). As a free-living amoeba, N. fowleri does not need a mammalian host; indeed, it can be accurately described as an accidental opportunistic pathogen. While most opportunistic infections occur in humans who are immunocompromised, there are no reported immune dysfunctions associated with N. fowleri infection. Therefore, the basis for N. fowleri opportunism is not known, and the reasons why some humans develop PAM while others do not are simply not well understood. It is reasonable to speculate that local or acute immune failures, potentially even a lack of prior adaptive immunity, are related to disease susceptibility. Careful immune profiling and characterization of the in vivo immune response to N. fowleri in a mammalian host are desperately needed to understand which host factors are critical to defense, and how these responses might be compromised in a way that results in lethal infection. To identify genes and pathways that provide resistance against in vivo N. fowleri infection, we generated surface reactive monoclonal antibodies (Abs) that provide rapid amoeba detection and quantification in vivo. Interestingly, N. fowleri binding Abs have been readily detected in the serum and saliva of humans and animals suggesting that non-lethal exposure drives a humoral immune response against the amoeba. Yet, how Abs might interact with Naegleria in vivo or contribute to preventing lethal infection is not well understood. In this study, we have generated and characterized a monoclonal antibody (Ab), Clone 2B6, that recognizes a glycosylated surface antigen present in cultured in vitro N. fowleri as well as mouse passaged N. fowleri. When clone 2B6 binds to N. fowleri, it inhibits amoeba motility and feeding behavior, leading to strong growth inhibition. Mice treated systemically and intracerebrally with Ab displayed a delayed disease onset and prolonged survival. In addition, we found that enhancing immune-directed effector activity via antibody isotype could further enhance survival without obvious immunopathogenic side effects. These findings show the potential for antibody treatment as an additional therapeutic to those used currently in PAM.
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Affiliation(s)
- Annie Park Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Ching-Wen Chen
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Xiaoe Liang
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Dongmei Liao
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - Masayuki Kuraoka
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - E Ashley Moseman
- Department of Integrative Immunobiology, Duke University School of Medicine, Durham, North Carolina, USA
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Borkens Y. The Pathology of the Brain Eating Amoeba Naegleria fowleri. Indian J Microbiol 2024; 64:1384-1394. [PMID: 39282207 PMCID: PMC11399382 DOI: 10.1007/s12088-024-01218-5] [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: 10/01/2023] [Accepted: 02/02/2024] [Indexed: 09/18/2024] Open
Abstract
The genus Naegleria is a taxonomic subfamily consisting of 47 free-living amoebae. The genus can be found in warm aqueous or soil habitats worldwide. The species Naegleria fowleri is probably the best-known species of this genus. As a facultative parasite, the protist is not dependent on hosts to complete its life cycle. However, it can infect humans by entering the nose during water contact, such as swimming, and travel along the olfactory nerve to the brain. There it causes a purulent meningitis (primary amoebic meningoencephalitis or PAME). Symptoms are severe and death usually occurs within the first week. PAME is a frightening infectious disease for which there is neither a proven cure nor a vaccine. In order to contain the disease and give patients any chance to survival, action must be taken quickly. A rapid diagnosis is therefore crucial. PAME is diagnosed by the detection of amoebae in the liquor and later in the cerebrospinal fluid. For this purpose, CSF samples are cultured and stained and finally examined microscopically. Molecular techniques such as PCR or ELISA support the microscopic analysis and secure the diagnosis.
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Affiliation(s)
- Yannick Borkens
- Institut für Pathologie, Charité Campus Mitte, Virchowweg 15, Charité, 10117 Berlin, Germany
- Humboldt-Universität zu Berlin, Unter den Linden 6, 10117 Berlin, Germany
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Köseoğlu AE, Özgül F, Işıksal EN, Şeflekçi Y, Tülümen D, Özgültekin B, Deniz Köseoğlu G, Özyiğit S, Ihlamur M, Ekenoğlu Merdan Y. In silico discovery of diagnostic/vaccine candidate antigenic epitopes and a multi-epitope peptide vaccine (NaeVac) design for the brain-eating amoeba Naegleria fowleri causing human meningitis. Gene 2024; 902:148192. [PMID: 38253295 DOI: 10.1016/j.gene.2024.148192] [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: 09/05/2023] [Revised: 12/14/2023] [Accepted: 01/18/2024] [Indexed: 01/24/2024]
Abstract
Naegleria fowleri, the brain-eating amoeba, is a free-living amoeboflagellate with three different life cycles (trophozoite, flagellated, and cyst) that lives in a variety of habitats around the world including warm freshwater and soil. It causes a disease called naegleriasis leading meningitis and primary amoebic meningoencephalitis (PAM) in humans. N. fowleri is transmitted through contaminated water sources such as insufficiently chlorinated swimming pool water or contaminated tap water, and swimmers are at risk. N. fowleri is found all over the world, and most infections were reported in both developed and developing countries with high mortality rates and serious clinical findings. Until now, there is no FDA approved vaccine and early diagnosis is urgent against this pathogen. In this study, by analyzing the N. fowleri vaccine candidate proteins (Mp2CL5, Nfa1, Nf314, proNP-A and proNP-B), it was aimed to discover diagnostic/vaccine candidate epitopes and to design a multi-epitope peptide vaccine against this pathogen. After the in silico evaluation, three prominent diagnostic/vaccine candidate epitopes (EAKDSK, LLPHIRILVY, and FYAKLLPHIRILVYS) with the highest antigenicities were discovered and a potentially highly immunogenic/antigenic multi-epitope peptide vaccine (NaeVac) was designed against the brain-eating amoeba N. fowleri causing human meningitis.
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Affiliation(s)
- Ahmet Efe Köseoğlu
- Duisburg-Essen University, Faculty of Chemistry, Department of Environmental Microbiology and Biotechnology, Essen, Germany.
| | - Filiz Özgül
- Biruni University, Faculty of Engineering and Natural Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey
| | - Elif Naz Işıksal
- Biruni University, Faculty of Engineering and Natural Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey; Biruni University, Faculty of Pharmacy, Department of Pharmacy, Istanbul, Turkey
| | - Yusuf Şeflekçi
- Biruni University, Faculty of Engineering and Natural Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey
| | - Deniz Tülümen
- Biruni University, Faculty of Engineering and Natural Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey
| | - Buminhan Özgültekin
- Bogaziçi University, Faculty of Arts and Sciences, Department of Molecular Biology and Genetics, Istanbul, Turkey
| | | | - Sena Özyiğit
- Biruni University, Faculty of Engineering and Natural Sciences, Department of Biomedical Engineering, Istanbul, Turkey
| | - Murat Ihlamur
- Biruni University, Vocational School, Department of Electronics and Automation, Istanbul, Turkey; Yıldız Technical University, Graduate School of Science and Engineering, Department of Bioengineering, Istanbul, Turkey
| | - Yağmur Ekenoğlu Merdan
- Biruni University, Faculty of Medicine, Department of Medical Microbiology, Istanbul, Turkey
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Alfaro-Sifuentes R, Lares-Jiménez LF, Rojas-Hernández S, Carrasco-Yépez MM, Rojas-Ortega DA, Rodriguez-Anaya LZ, Gonzalez-Galaviz JR, Lares-Villa F. Immunogens in Balamuthia mandrillaris: a proteomic exploration. Parasitol Res 2024; 123:173. [PMID: 38536506 DOI: 10.1007/s00436-024-08193-2] [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: 02/01/2024] [Accepted: 03/20/2024] [Indexed: 04/04/2024]
Abstract
Balamuthia mandrillaris is the causative agent of granulomatous amoebic encephalitis, a rare and often fatal infection affecting the central nervous system. The amoeba is isolated from diverse environmental sources and can cause severe infections in both immunocompromised and immunocompetent individuals. Given the limited understanding of B. mandrillaris, our research aimed to explore its protein profile, identifying potential immunogens crucial for early granulomatous amoebic encephalitis diagnosis. Cultures of B. mandrillaris and other amoebas were grown under axenic conditions, and total amoebic extracts were obtained. Proteomic analyses, including two-dimensional electrophoresis and mass spectrometry, were performed. A 50-kDa band showed a robust recognition of antibodies from immunized BALB/c mice; peptides contained in this band were matched with elongation factor-1 alpha, which emerged as a putative key immunogen. Besides, lectin blotting revealed the presence of glycoproteins in B. mandrillaris, and confocal microscopy demonstrated the focal distribution of the 50-kDa band throughout trophozoites. Cumulatively, these observations suggest the participation of the 50-kDa band in adhesion and recognition mechanisms. Thus, these collective findings demonstrate some protein characteristics of B. mandrillaris, opening avenues for understanding its pathogenicity and developing diagnostic and therapeutic strategies.
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Affiliation(s)
- Rosalía Alfaro-Sifuentes
- Programa de Doctorado en Ciencias Especialidad en Biotecnología, Departamento de Biotecnología y Ciencias Alimentarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
| | - Luis Fernando Lares-Jiménez
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México
| | - Saul Rojas-Hernández
- Laboratorio de Inmunología Molecular, Instituto Politécnico Nacional, Escuela Superior de Medicina, Salvador Díaz Mirón Esq. Plan de San Luis S/N, Miguel Hidalgo, Casco de Santo Tomas, Ciudad de México, México
| | | | - Diego Alexander Rojas-Ortega
- Centro de Investigación en Ciencias de La Salud (CICSA), FCS, Universidad Anáhuac México, 52786, Huixquilucan, Estado de México, México
| | | | | | - Fernando Lares-Villa
- Departamento de Ciencias Agronómicas y Veterinarias, Instituto Tecnológico de Sonora, 85000, Ciudad Obregón, Sonora, México.
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Naveed M, Ali U, Aziz T, Jabeen K, Arif MH, Alharbi M, Alasmari AF, Albekairi TH. Development and immunological evaluation of an mRNA-based vaccine targeting Naegleria fowleri for the treatment of primary amoebic meningoencephalitis. Sci Rep 2024; 14:767. [PMID: 38191579 PMCID: PMC10774437 DOI: 10.1038/s41598-023-51127-8] [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: 11/21/2023] [Accepted: 12/31/2023] [Indexed: 01/10/2024] Open
Abstract
More than 95% of patients fall victim to primary amoebic meningoencephalitis (PAM), a fatal disease attacking the central nervous system. Naegleria fowleri, a brain-eating microorganism, is PAM's most well-known pathogenic ameboflagellate. Despite the use of antibiotics, the fatality rate continues to rise as no clinical trials have been conducted against this disease. To address this, we mined the UniProt database for pathogenic proteins and selected assumed epitopes to create an mRNA-based vaccine. We identified thirty B-cell and T-cell epitopes for the vaccine candidate. These epitopes, secretion boosters, subcellular trafficking structures, and linkers were used to construct the vaccine candidate. Through predictive modeling and confirmation via the Ramachandran plot (with a quality factor of 92.22), we assessed secondary and 3D structures. The adjuvant RpfE was incorporated to enhance the vaccine construct's immunogenicity (GRAVY index: 0.394, instability index: 38.99, antigenicity: 0.8). The theoretical model of immunological simulations indicated favorable responses from both innate and adaptive immune cells, with memory cells expected to remain active for up to 350 days post-vaccination, while the antigen was eliminated from the body within 24 h. Notably, strong interactions were observed between the vaccine construct and TLR-4 (- 11.9 kcal/mol) and TLR-3 (- 18.2 kcal/mol).
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Affiliation(s)
- Muhammad Naveed
- Department of Biotechnology, Faculty of Science and Technology, University of Central Punjab, Lahore, 54590, Punjab, Pakistan.
| | - Urooj Ali
- Department of Biotechnology, Quaid-I-Azam University Islamabad, Islamabad, 45320, Pakistan
| | - Tariq Aziz
- Laboratory of Animal Health, Food Hygiene and Quality, Department of Agriculture, University of Ioannina, 47132, Arta, Greece.
| | - Khizra Jabeen
- Department of Biotechnology, Faculty of Science and Technology, University of Central Punjab, Lahore, 54590, Punjab, Pakistan
| | - Muhammad Hammad Arif
- Department of Biotechnology, Faculty of Science and Technology, University of Central Punjab, Lahore, 54590, Punjab, Pakistan
| | - Metab Alharbi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, 11451, Riyadh, Saudi Arabia
| | - Abdullah F Alasmari
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, 11451, Riyadh, Saudi Arabia
| | - Thamer H Albekairi
- Department of Pharmacology and Toxicology, College of Pharmacy, King Saud University, Post Box 2455, 11451, Riyadh, Saudi Arabia
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