1
|
Mintsa-Nguema R, Zoa-Assoumou S, Mewono L, M’Bondoukwé NP, Essono P, Mengue-Me-Ngou-Milama K, Boukandou-Mounanga M, Ndong-Ngomo JM, Mintsa-Ndong A, Ngoungou EB, Bouyou-Akotet MK, Mbongo-Kama E. Could pooled samples method affect SARS-CoV-2 diagnosis accuracy using BGI and Sansure-Biotech RT-PCR kits used in Gabon, Central Africa? PLoS One 2022; 17:e0262733. [PMID: 35061822 PMCID: PMC8782308 DOI: 10.1371/journal.pone.0262733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 01/04/2022] [Indexed: 11/29/2022] Open
Abstract
This study aims at establishing specimens pooling approach for the detection of SARS-CoV-2 using the RT-PCR BGI and Sansure-Biotech kits used in Gabon. To validate this approach, 14 positive samples, stored at -20°C for three to five weeks were analyzed individually (as gold standard) and in pools of five, eight and ten in the same plate. We created 14 pools of 5, 8 and 10 samples using 40 μL from each of the selected positive samples mixed with 4, 7 and 9 confirmed negative counterparts in a total volume of 200 μL, 320 μL and 400 μL for the pools of 5, 8 and 10 respectively. Both individual and pooled samples testing was conducted according to the BGI and Sansure-Biotech RT-PCR protocols used at the Professor Daniel Gahouma Laboratory (PDGL). Furthermore, the pooling method was also tested by comparing results of 470 unselected samples tested in 94 pools and individually. Results of our experiment showed that using a BGI single positive sample with cycle threshold (Ct) value of 28.42, confirmed by individual testing, detection occurred in all the pools. On the contrary samples with Ct >31 were not detected in pools of 10 and for these samples (Ct value as high as 37.17) their detection was possible in pool of 8. Regarding the Sansure-Biotech kit, positive samples were detected in all the pool sizes tested, irrespective of their Ct values. The specificity of the pooling method was 100% for the BGI and Sansure-Biotech RT-PCR assays. The present study found an increase in the Ct values with pool size for the BGI and Sansure-Biotech assays. This trend was statistically significant (Pearson’s r = 0.978; p = 0,022) using the BGI method where the mean Ct values were 24.04±1.1, 26.74±1.3, 27.91±1.1 and 28.32±1.1 for the individual, pool of 5, 8 and 10 respectively. The testing of the 470 samples showed that one of the 94 pools had a positive test similar to the individual test using the BGI and Sansure-Biotech kits. The saving of time and economizing test reagents by using the pooling method were demonstrated in this study. Ultimately, the pooling method could be used for the diagnosis of SARS-CoV-2 without modifying the accuracy of results in Gabon. We recommend a maximum pool size of 8 for the BGI kit. For the Sansure-Biotech kit, a maximum pool size of 10 can be used without affecting its accuracy compared to the individual testing.
Collapse
Affiliation(s)
- Rodrigue Mintsa-Nguema
- Research Institute in Tropical Ecology, National Center for Scientific and Technological Research, Libreville, Gabon
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- * E-mail:
| | - Samira Zoa-Assoumou
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- Department of Bacteriology-Virology, University of Health Science, Libreville, Gabon
| | - Ludovic Mewono
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- Department of Biology, Higher Normal School, Libreville, Gabon
| | - Noé P. M’Bondoukwé
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- Department of Parasitology-Mycology, University of Health Science, Libreville, Gabon
| | - Paulin Essono
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- National Laboratory of Public Health, Libreville, Gabon
| | - Krystina Mengue-Me-Ngou-Milama
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- National Laboratory of Public Health, Libreville, Gabon
| | - Marlaine Boukandou-Mounanga
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- Institute of Pharmacopeia and Traditional Medicine, National Center for Scientific and Technological Research, Libreville, Gabon
| | - Jacques M. Ndong-Ngomo
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
- Department of Parasitology-Mycology, University of Health Science, Libreville, Gabon
| | | | - Edgard B. Ngoungou
- Department of Parasitology-Mycology, University of Health Science, Libreville, Gabon
| | | | - Elvyre Mbongo-Kama
- Professor Daniel Gahouma Laboratory, Ministry of Health, Libreville, Gabon
| |
Collapse
|
2
|
Mengome LE, Mewono L, Mboma R, Engohang-Ndong J, Aboughe Angone S. Ethnobotanical survey and phytochemical screening of anti-snakebite plants used in Bissok District of Gabon. Biodiversitas 2021. [DOI: 10.13057/biodiv/d220821] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Abstract. Mengome, Mewono L, Mboma R, Engohang-Ndong J, Angone SA. 2021. Ethnobotanical survey and phytochemical screening of anti-snakebite plants used in Bissok District of Gabon. Biodiversitas 22: 3264-3275. Snakebites remain a major health issue in tropical and subtropical regions in the world. The limited access of antivenom sera in remote areas of many countries forces populations to rely on plant-based remedies to manage snakebite-induced injury. In this study, we conducted an ethnobotanical survey of medicinal plants used for the management of snakebites in the district of Bissok (Northern Gabon). After collecting and verifying the authenticity of the plants, we further performed their phytochemical analysis. The procedure used in this study involved a structured questionnaire and direct interviews of local populations. Overall, data collected on-site included local names, the part of the plant used, the preparation, and the route of administration. The presence of some phytochemical compounds was determined according to standard methods. Overall, a total of 29 species of plants belonging to 20 different families were reported to be used to treat snakebites. The plants used were herbs (44.80%), trees (24.10%), shrubs (20.70%), liana (10.30%), and rhizomes (6.90%). They were mainly used as poultice or crush, and to a lesser extent as decoction and maceration. Regarding the route of administration, interviewees reported mainly external use on the site of the bite. Concerning the chemical composition, we found that the antivenom plants were rich in chemical compounds known to have antivenom, antipyretic and antimicrobial properties, e.g. alkaloids, terpenoids, flavonoids, steroids, coumarins, phenols, tannins gallic Our results open avenues to develop venom enzyme inhibitory assays.
Collapse
|
3
|
Drakeley C, Abdulla S, Agnandji ST, Fernandes JF, Kremsner P, Lell B, Mewono L, Bache BE, Mihayo MG, Juma O, Tanner M, Tahita MC, Tinto H, Diallo S, Lompo P, D'Alessandro U, Ogutu B, Otieno L, Otieno S, Otieno W, Oyieko J, Asante KP, Dery DBE, Adjei G, Adeniji E, Atibilla D, Owusu-Agyei S, Greenwood B, Gesase S, Lusingu J, Mahende C, Mongi R, Segeja M, Adjei S, Agbenyega T, Agyekum A, Ansong D, Bawa JT, Boateng HO, Dandalo L, Escamilla V, Hoffman I, Maenje P, Martinson F, Carter T, Leboulleux D, Kaslow DC, Usuf E, Pirçon JY, Bahmanyar ER. Longitudinal estimation of Plasmodium falciparum prevalence in relation to malaria prevention measures in six sub-Saharan African countries. Malar J 2017; 16:433. [PMID: 29078773 PMCID: PMC5658967 DOI: 10.1186/s12936-017-2078-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 10/19/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Plasmodium falciparum prevalence (PfPR) is a widely used metric for assessing malaria transmission intensity. This study was carried out concurrently with the RTS,S/AS01 candidate malaria vaccine Phase III trial and estimated PfPR over ≤ 4 standardized cross-sectional surveys. METHODS This epidemiology study (NCT01190202) was conducted in 8 sites from 6 countries (Burkina Faso, Gabon, Ghana, Kenya, Malawi, and Tanzania), between March 2011 and December 2013. Participants were enrolled in a 2:1:1 ratio according to age category: 6 months-4 years, 5-19 years, and ≥ 20 years, respectively, per year and per centre. All sites carried out surveys 1-3 while survey 4 was conducted only in 3 sites. Surveys were usually performed during the peak malaria parasite transmission season, in one home visit, when medical history and malaria risk factors/prevention measures were collected, and a blood sample taken for rapid diagnostic test, microscopy, and haemoglobin measurement. PfPR was estimated by site and age category. RESULTS Overall, 6401 (survey 1), 6411 (survey 2), 6400 (survey 3), and 2399 (survey 4) individuals were included in the analyses. In the 6 months-4 years age group, the lowest prevalence (assessed using microscopy) was observed in 2 Tanzanian centres (4.6% for Korogwe and 9.95% for Bagamoyo) and Lambaréné, Gabon (6.0%), while the highest PfPR was recorded for Nanoro, Burkina Faso (52.5%). PfPR significantly decreased over the 3 years in Agogo (Ghana), Kombewa (Kenya), Lilongwe (Malawi), and Bagamoyo (Tanzania), and a trend for increased PfPR was observed over the 4 surveys for Kintampo, Ghana. Over the 4 surveys, for all sites, PfPR was predominantly higher in the 5-19 years group than in the other age categories. Occurrence of fever and anaemia was associated with high P. falciparum parasitaemia. Univariate analyses showed a significant association of anti-malarial treatment in 4 surveys (odds ratios [ORs]: 0.52, 0.52, 0.68, 0.41) and bed net use in 2 surveys (ORs: 0.63, 0.68, 1.03, 1.78) with lower risk of malaria infection. CONCLUSION Local PfPR differed substantially between sites and age groups. In children 6 months-4 years old, a significant decrease in prevalence over the 3 years was observed in 4 out of the 8 study sites. Trial registration Clinical Trials.gov identifier: NCT01190202:NCT. GSK Study ID numbers: 114001.
Collapse
Affiliation(s)
- Chris Drakeley
- London School of Hygiene and Tropical Medicine, London, UK
| | - Salim Abdulla
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania.
| | - Selidji Todagbe Agnandji
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - José Francisco Fernandes
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Peter Kremsner
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Bertrand Lell
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Ludovic Mewono
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Bache Emmanuel Bache
- Albert Schweitzer Hospital, Lambaréné, Gabon and Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Michael Gabriel Mihayo
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania
| | - Omar Juma
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania
| | - Marcel Tanner
- Ifakara Institute of Health, Bagamoyo Research and Training Centre, Bagamoyo District Hospital, P.O. Box 74, Bagamoyo, Tanzania.,Swiss Tropical and Public Health Institute, Basel, Switzerland.,University of Basel, Basel, Switzerland
| | | | - Halidou Tinto
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | - Salou Diallo
- Institut de Recherche en Sciences de la Santé, Nanoro, Burkina Faso
| | | | - Umberto D'Alessandro
- London School of Hygiene and Tropical Medicine, London, UK.,Medical Research Council Unit, The Gambia, Banjul, Gambia
| | | | | | | | | | | | | | | | - George Adjei
- Kintampo Health Research Center, Kintampo, Ghana
| | | | | | - Seth Owusu-Agyei
- London School of Hygiene and Tropical Medicine, London, UK.,Kintampo Health Research Center, Kintampo, Ghana
| | - Brian Greenwood
- London School of Hygiene and Tropical Medicine, London, UK.,Kintampo Health Research Center, Kintampo, Ghana
| | - Samwel Gesase
- National Institute for Medical Research, Korogwe, Tanzania
| | - John Lusingu
- National Institute for Medical Research, Korogwe, Tanzania
| | - Coline Mahende
- National Institute for Medical Research, Korogwe, Tanzania
| | - Robert Mongi
- National Institute for Medical Research, Korogwe, Tanzania
| | - Method Segeja
- National Institute for Medical Research, Korogwe, Tanzania
| | - Samuel Adjei
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Tsiri Agbenyega
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Alex Agyekum
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - Daniel Ansong
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | - John Tanko Bawa
- Kwame Nkrumah University of Science and Technology, Agogo, Ghana
| | | | | | | | | | - Peter Maenje
- University of North Carolina Project, Lilongwe, Malawi
| | | | - Terrell Carter
- The PATH Malaria Vaccine Initiative, Washington, D.C., USA
| | | | - David C Kaslow
- The PATH Malaria Vaccine Initiative, Washington, D.C., USA
| | - Effua Usuf
- Medical Research Council Unit, The Gambia, Banjul, Gambia.,GSK Vaccines, Wavre, Belgium
| | | | | |
Collapse
|
4
|
Boukandou Mounanga M, Mewono L, Aboughe Angone S. Toxicity studies of medicinal plants used in sub-Saharan Africa. J Ethnopharmacol 2015; 174:618-627. [PMID: 26087230 DOI: 10.1016/j.jep.2015.06.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2015] [Revised: 05/13/2015] [Accepted: 06/07/2015] [Indexed: 06/04/2023]
Abstract
In sub-Saharan Africa, traditional medicine is widely used in rural and urban areas also. This is essentially due to the prohibitive cost of pharmaceutical-based medicine and the low incomes of a major part of the population. In addition, the efficacies of many of these traditional and plant-based medicines are proven, but the fact remains that certain plants used in traditional medicine have toxic effects. It is in this perspective that we investigated by bibliographic literature on the toxicity of plants used in traditional medicine. It is crucial to gain knowledge on these plant-based medicines prepared and prescribed by practitioners, particularly in terms of toxicity, composition, specific efficacy of disease and to advise practitioners of this alternative medicine on the protection and security of patients.
Collapse
Affiliation(s)
- Marlaine Boukandou Mounanga
- Pharmacopeia and Traditional Medicine Institute: National Center of Technological and Scientific Research, Libreville, Gabon.
| | - Ludovic Mewono
- Groupe de Recherche en Immunologie, Microbiologie appliquée, Hygiène et Physiologie (GRIMAH.P), Département des Sciences de la Vie et de la Terre- Ecole Normale Supérieure, BP 17009 Libreville, Gabon.
| | - Sophie Aboughe Angone
- Pharmacopeia and Traditional Medicine Institute: National Center of Technological and Scientific Research, Libreville, Gabon.
| |
Collapse
|
5
|
Angone SA, Mewono L, Mounanga MB, Medzegue S, Ella Mendene HF, Mba Ndong JG, Djoba Siawaya JF, Souza A. Phytochemical screening and cytotoxicity studies of Chrysophyllum pruniforme Pierre ex Engl. barks. Pharmacognosy Res 2013; 5:195-9. [PMID: 23900977 PMCID: PMC3719262 DOI: 10.4103/0974-8490.112427] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 11/06/2012] [Accepted: 05/22/2013] [Indexed: 12/31/2022] Open
Abstract
Background: Chrysophyllum pruniforme of family sapotaceae is a plant used in traditional medicine in Gabon. Materials and Methods: In this study, C. pruniforme barks were subjected to phytochemical screening and cytotoxicity investigations. Different concentrations of aqueous and total phenolic extract were tested on mice and on human erythrocytes. Results: Phytochemical screening of C. pruniforme barks revealed the presence of flavonoids, saponins, and tannins, reducing sugars, polyphenols and traces of anthraquinones. When tested in vitro, aqueous and the phenolic extracts showed hemolytic activities on human erythrocytes with phenolic compounds being more cytotoxic than aqueous extracts. In vivo study of toxicity, allowed to determine the LD50 at 90 mg/kg for the doses of 50, 150 and 250 mg/kg of body weight. Conclusion: These data indicate in one hand that C. pruniforme is rich in phenolic compounds and that the aqueous and total phenolic extracts could be considered as toxic for mice and maybe potentially toxic to humans in the other hand.
Collapse
Affiliation(s)
- Sophie Aboughe Angone
- Pharmacopea and Traditional Medicine Institute, National Center of Technological and Scientific Research, Lambaréné, Gabon
| | | | | | | | | | | | | | | |
Collapse
|
6
|
Labuda LA, Ateba-Ngoa U, Feugap EN, Heeringa JJ, van der Vlugt LEPM, Pires RBA, Mewono L, Kremsner PG, van Zelm MC, Adegnika AA, Yazdanbakhsh M, Smits HH. Alterations in peripheral blood B cell subsets and dynamics of B cell responses during human schistosomiasis. PLoS Negl Trop Dis 2013; 7:e2094. [PMID: 23505586 PMCID: PMC3591311 DOI: 10.1371/journal.pntd.0002094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Accepted: 01/23/2013] [Indexed: 11/19/2022] Open
Abstract
Antibody responses are thought to play an important role in control of Schistosoma infections, yet little is known about the phenotype and function of B cells in human schistosomiasis. We set out to characterize B cell subsets and B cell responses to B cell receptor and Toll-like receptor 9 stimulation in Gabonese schoolchildren with Schistosoma haematobium infection. Frequencies of memory B cell (MBC) subsets were increased, whereas naive B cell frequencies were reduced in the schistosome-infected group. At the functional level, isolated B cells from schistosome-infected children showed higher expression of the activation marker CD23 upon stimulation, but lower proliferation and TNF-α production. Importantly, 6-months after 3 rounds of praziquantel treatment, frequencies of naive B cells were increased, MBC frequencies were decreased and with the exception of TNF-α production, B cell responsiveness was restored to what was seen in uninfected children. These data show that S. haematobium infection leads to significant changes in the B cell compartment, both at the phenotypic and functional level. Schistosomiasis affects over 200 million people and especially children in developing countries. It causes general hyporesponsiveness of the immune system, which until now has predominantly been described for various T cell subsets as well as dendritic cells. B cells in this context have not yet been investigated. To address this question, we phenotyped B cell subsets present in peripheral blood from S. haematobium infected and uninfected schoolchildren living in an endemic area in Lambaréné, Gabon. Children with schistosomiasis had an increased frequency of various memory B cell subsets, including subsets associated with B cell exhaustion, and a concomitant decrease in naive B cells. To study the effect of Schistosoma infection on B cells in more detail we isolated peripheral blood B cells and found that B cells from infected children had a reduced capacity to proliferate and produce TNF-α in response to both B cell receptor and Toll-like receptor stimulation. These results provide new insights into the role of B cells in the host immune response to schistosomiasis and may provide a novel target for therapeutic strategies.
Collapse
Affiliation(s)
- Lucja A. Labuda
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Ulysse Ateba-Ngoa
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Eliane Ngoune Feugap
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Jorn J. Heeringa
- Department of Immunology, Erasmus MC, Rotterdam, The Netherlands
| | | | - Regina B. A. Pires
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Ludovic Mewono
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
| | - Peter G. Kremsner
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | | | - Ayola A. Adegnika
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- Centre de Recherches Médicales de Lambaréné (CERMEL), Lambaréné, Gabon
- Institute of Tropical Medicine, University of Tübingen, Tübingen, Germany
| | - Maria Yazdanbakhsh
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
| | - Hermelijn H. Smits
- Department of Parasitology, Leiden University Medical Center, Leiden, The Netherlands
- * E-mail:
| |
Collapse
|
7
|
Agnandji ST, Fendel R, Mestré M, Janssens M, Vekemans J, Held J, Gnansounou F, Haertle S, von Glasenapp I, Oyakhirome S, Mewono L, Moris P, Lievens M, Demoitie MA, Dubois PM, Villafana T, Jongert E, Olivier A, Cohen J, Esen M, Kremsner PG, Lell B, Mordmüller B. Induction of Plasmodium falciparum-specific CD4+ T cells and memory B cells in Gabonese children vaccinated with RTS,S/AS01(E) and RTS,S/AS02(D). PLoS One 2011; 6:e18559. [PMID: 21494604 PMCID: PMC3073948 DOI: 10.1371/journal.pone.0018559] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 03/11/2011] [Indexed: 12/04/2022] Open
Abstract
UNLABELLED The recombinant circumsporozoite protein (CS) based vaccine, RTS,S, confers protection against Plasmodium falciparum infection in controlled challenge trials and in field studies. The RTS,S recombinant antigen has been formulated with two adjuvant systems, AS01 and AS02, which have both been shown to induce strong specific antibody responses and CD4 T cell responses in adults. As infants and young children are particularly susceptible to malaria infection and constitute the main target population for a malaria vaccine, we have evaluated the induction of adaptive immune responses in young children living in malaria endemic regions following vaccination with RTS,S/AS01(E) and RTS,S/AS02(D). Our data show that a CS-specific memory B cell response is induced one month after the second and third vaccine dose and that CS-specific antibodies and memory B cells persist up to 12 months after the last vaccine injection. Both formulations also induced low but significant amounts of CS-specific IL-2(+) CD4(+) T cells one month after the second and third vaccine dose, upon short-term in vitro stimulation of whole blood cells with peptides covering the entire CS derived sequence in RTS,S. These results provide evidence that both RTS,S/AS01(E) and RTS,S/AS02(D) induced adaptive immune responses including antibodies, circulating memory B cells and CD4(+) T cells directed against P. falciparum CS protein. TRIAL REGISTRATION ClinicalTrials.gov NCT00307021.
Collapse
|
8
|
Mordmüller B, Szywon K, Greutelaers B, Esen M, Mewono L, Treut C, Mürbeth RE, Chilengi R, Noor R, Kilama WL, Imoukhuede EB, Imbault N, Leroy O, Theisen M, Jepsen S, Milligan P, Fendel R, Kremsner PG, Issifou S. Safety and immunogenicity of the malaria vaccine candidate GMZ2 in malaria-exposed, adult individuals from Lambaréné, Gabon. Vaccine 2010; 28:6698-703. [PMID: 20696154 DOI: 10.1016/j.vaccine.2010.07.085] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2010] [Revised: 07/23/2010] [Accepted: 07/27/2010] [Indexed: 11/18/2022]
Abstract
Malaria is still one of the major public health threats in sub-Saharan Africa. An effective vaccine could be a sustainable control measure that can be integrated into existing health infrastructures. The malaria vaccine candidate GMZ2 is a recombinant fusion protein of conserved parts of Plasmodium falciparum Glutamate Rich Protein and Merozoite Surface Protein 3 adjuvanted with aluminium hydroxide. GMZ2 is immunogenic and well tolerated in malaria-naive adults from Germany. To assess safety and immunogenicity in malaria-exposed individuals, 40 adults from Lambaréné, Gabon were randomly assigned to receive either 100 μg GMZ2 or a rabies control vaccine three times in monthly intervals. Both vaccines were well tolerated. One month after a full course of vaccination, GMZ2-vaccinated individuals had 1.4-fold (95% confidence interval: [1.1, 1.7]) higher baseline-corrected anti-GMZ2 antibody levels and more GMZ2-specific memory B-cells compared to the rabies group (p=0.039), despite a high prevalence of GMZ2-specific immune reactivity due to previous intense exposure to P. falciparum.
Collapse
|
9
|
Mewono L, Agnandji ST, Matondo Maya DW, Mouima AMN, Iroungou BA, Issifou S, Kremsner PG. Malaria antigen-mediated enhancement of interleukin-21 responses of peripheral blood mononuclear cells in African adults. Exp Parasitol 2009; 122:37-40. [PMID: 19545527 DOI: 10.1016/j.exppara.2009.01.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2009] [Accepted: 01/13/2009] [Indexed: 10/21/2022]
Abstract
We recently showed that IL-21 is associated with high level of anti-EBA-175 IgG1 and IgG3. Here we have investigated the ability of two malarial antigens, Glutamate-rich protein and merozoite surface protein 3 to induce IL-21 production from PBMCs from malaria-exposed and non-exposed donors. We found that malaria-exposed donors produced significantly more IL-21 compared to non-exposed donors. These data suggest that IL-21 could be involved in the acquisition of immunity to malaria.
Collapse
Affiliation(s)
- Ludovic Mewono
- Medical Research Unit, Albert Schweitzer Hospital, P.O. Box 118, Lambaréné, Gabon.
| | | | | | | | | | | | | |
Collapse
|
10
|
Mewono L, Agnandji ST, Matondo Maya DW, Mouima AMN, Iroungou BA, Issifou S, Kremsner PG, Mavoungou E. WITHDRAWN: Malaria Antigen-Mediated Enhancement of Interleukin-21 responses of Peripheral Blood Mononuclear Cells in African Adults. Exp Parasitol 2008. [DOI: 10.1016/j.exppara.2008.11.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
|
11
|
Mavoungou E, Held J, Mewono L, Kremsner PG. A Duffy binding-like domain is involved in the NKp30-mediated recognition of Plasmodium falciparum-parasitized erythrocytes by natural killer cells. J Infect Dis 2007; 195:1521-31. [PMID: 17436233 DOI: 10.1086/515579] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2006] [Accepted: 12/14/2006] [Indexed: 11/04/2022] Open
Abstract
The recent demonstration that purified natural killer (NK) cells lyse Plasmodium falciparum-parasitized red blood cells (Pf-pRBCs) suggests that innate immunity is important in malaria. NK cell killing--presumably an early host response to infection--requires intimate contact between NK natural cytotoxicity receptors (NCRs) and ligands expressed on the surface of Pf-pRBCs. We investigated whether the Duffy binding-like (DBL)-1 alpha domain of P. falciparum erythrocyte membrane protein-1 (PfEMP-1) expressed on parasitized erythrocytes rendered Pf-pRBCs susceptible to NK cell lysis. We showed that with NKp30-immunoglobulin and NKp46-immunoglobulin fusion proteins and DBL-1alpha peptides NCRs are involved in the NK cell-Pf-pRBC interaction. This interaction was direct, specific, and functional, leading to perforin production and granzyme B release. The prior treatment of NK cells with DBL-1 alpha peptides abolished both this interaction and killing activity, suggesting that DBL-1 alpha -NCRs interaction is the key recognition mechanism leading to parasite killing by NK cells.
Collapse
Affiliation(s)
- Elie Mavoungou
- Medical Research Unit, Albert Schweitzer Hospital, Lambarene, Gabon.
| | | | | | | |
Collapse
|