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Amoah AGB, Sagoe KW, Quakyi IA, Ayettey Anie HNG, Ayettey-Adamafio MNB, Ayettey Brew RNA, Newman-Nartey M, Nartey NO, Brightson KTC, Kessie G, Ayettey AS, Konotey-Ahulu FID. Further observations on hydrogen peroxide antisepsis and COVID-19 cases among healthcare workers and inpatients. J Hosp Infect 2022; 126:103-108. [PMID: 35594985 PMCID: PMC9113766 DOI: 10.1016/j.jhin.2022.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 04/28/2022] [Accepted: 05/08/2022] [Indexed: 11/29/2022]
Abstract
Background The use of prophylactic antisepsis to protect against coronavirus disease 2019 (COVID-19) has been suggested. This study investigated hydrogen peroxide antisepsis (HPA) at two hospitals in Ghana. Methods Cases of COVID-19 among healthcare workers (HCWs) using hydrogen peroxide (HP-HCWs) or not using hydrogen peroxide (NHP-HCWs), vaccinated or unvaccinated, were recorded at Shai-Osudoku Hospital (SODH), Dodowa, and Mount Olives Hospital (MOH), Techiman, between May 2020 and December 2021. The effect of HPA in all inpatients at MOH was also observed. Permutation tests were used to determine P values. Findings At SODH, there were 62 (13.5%) cases of COVID-19 among 458 NHP-HCWs but no cases among eight HP-HCWs (P=0.622) from May to December 2020. Between January and March 2021, 10 (2.7%) of 372 NHP-HCWs had COVID-19, but there were no cases among 94 HP-HCWs (P=0.206). At MOH, prior to HPA, 17 (20.2%) of 84 HCWs and five (1.4%) of 370 inpatients had COVID-19 in July 2020. From August 2020 to March 2021, two of 54 (3.7%) HCWs who stopped HPA had COVID-19; none of 32 NHP-HCWs contracted COVID-19. At SODH, none of 23 unvaccinated HP-HCWs and 35 (64%) of 55 unvaccinated NHP-HCWs had COVID-19 from April to December 2021 (P<0.0001). None of 34 vaccinated HP-HCWs and 53 (13.6%) of 390 vaccinated NHP-HCWs had COVID-19 (P=0.015). No inpatients on prophylactic HPA (total 7736) contracted COVID-19. Conclusion Regular, daily HPA protects HCWs from COVID-19, and curtails nosocomial spread of SARS-CoV-2.
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Affiliation(s)
- A G B Amoah
- Department of Medicine and Therapeutics, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - K W Sagoe
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - I A Quakyi
- Department of Biological Environmental and Occupational Health Sciences, School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - H N G Ayettey Anie
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle Bu Teaching Hospital, Accra, Ghana
| | - M N B Ayettey-Adamafio
- Department of Dental/Oral and Maxillofacial Surgery, Korle Bu Teaching Hospital, Korle Bu, Accra, Ghana
| | - R N A Ayettey Brew
- Department of Obstetrics and Gynaecology, Holy Family Hospital, Techiman, Bono East Region, Ghana
| | - M Newman-Nartey
- Department of Orthodontics and Pedodontics, University of Ghana Dental School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - N O Nartey
- Department of Oral Pathology and Oral Medicine, University of Ghana Dental School, College of Health Sciences, University of Ghana, Legon, Ghana
| | | | - G Kessie
- Mount Olives Hospital, Techiman, Bono East Region, Ghana
| | - A S Ayettey
- Department of Anatomy, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
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2
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Amoah GB, Quakyi IA, Sagoe KW, Ayettey-Anie HNG, Ayettey-Adamafio MNB, Ayettey Brew RNA, Newman-Nartey M, Nartey NO, Brightson KTC, Kessie G, Ayettey AS, Konotey-Ahulu FID. Re: Oral antiseptics against coronavirus: in-vitro and clinical evidence. J Hosp Infect 2021; 118:108-109. [PMID: 34487774 PMCID: PMC8414839 DOI: 10.1016/j.jhin.2021.08.024] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 08/29/2021] [Indexed: 02/07/2023]
Affiliation(s)
- G B Amoah
- University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
| | - I A Quakyi
- School of Public Health, College of Health Sciences, University of Ghana, Legon, Ghana
| | - K W Sagoe
- Department of Medical Microbiology, University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana.
| | - H N G Ayettey-Anie
- National Radiotherapy Oncology and Nuclear Medicine Centre, Korle Bu Teaching Hospital, Accra, Ghana
| | | | - R N A Ayettey Brew
- Department of Obstetrics and Gynecology, Korle Bu Teaching Hospital, Accra, Ghana
| | - M Newman-Nartey
- University of Ghana Dental School, College of Health Sciences, University of Ghana, Ghana
| | - N O Nartey
- University of Ghana Dental School, College of Health Sciences, University of Ghana, Ghana
| | | | - G Kessie
- Mount Olives Hospital (MO), Techiman, Bono East Region, Ghana
| | - A S Ayettey
- University of Ghana Medical School, College of Health Sciences, University of Ghana, Legon, Ghana
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3
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Ryan JR, Davé K, Collins KM, Hochberg L, Sattabongkot J, Coleman RE, Dunton RF, Bangs MJ, Mbogo CM, Cooper RD, Schoeler GB, Rubio-Palis Y, Magris M, Romer LI, Padilla N, Quakyi IA, Bigoga J, Leke RG, Akinpelu O, Evans B, Walsey M, Patterson P, Wirtz RA, Chan AST. Extensive multiple test centre evaluation of the VecTest malaria antigen panel assay. Med Vet Entomol 2002; 16:321-327. [PMID: 12243234 DOI: 10.1046/j.1365-2915.2002.00368.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
To determine which species and populations of Anopheles transmit malaria in any given situation, immunological assays for malaria sporozoite antigen can replace traditional microscopical examination of freshly dissected Anopheles. We developed a wicking assay for use with mosquitoes that identifies the presence or absence of specific peptide epitopes of circumsporozoite (CS) protein of Plasmodium falciparum and two strains of Plasmodium vivax (variants 210 and 247). The resulting assay (VecTest Malaria) is a rapid, one-step procedure using a 'dipstick' test strip capable of detecting and distinguishing between P. falciparum and P. vivax infections in mosquitoes. The objective of the present study was to test the efficacy, sensitivity, stability and field-user acceptability of this wicking dipstick assay. In collaboration with 16 test centres world-wide, we evaluated more than 40 000 units of this assay, comparing it to the standard CS ELISA. The 'VecTest Malaria' was found to show 92% sensitivity and 98.1% specificity, with 97.8% accuracy overall. In accelerated storage tests, the dipsticks remained stable for > 15 weeks in dry conditions up to 45 degrees C and in humid conditions up to 37 degrees C. Evidently, this quick and easy dipstick test performs at an acceptable level of reliability and offers practical advantages for field workers needing to make rapid surveys of malaria vectors.
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Affiliation(s)
- J R Ryan
- Department of Entomology, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA.
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4
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Ellis JM, Hoyer RJ, Costello CN, Mshana RN, Quakyi IA, Mshana MN, Diaby B, Traore M, Johnson AH, Hurley CK. HLA-B allele frequencies in Côte d'Ivoire defined by direct DNA sequencing: identification of HLA-B*1405, B*4410, and B*5302. Tissue Antigens 2001; 57:339-43. [PMID: 11380943 DOI: 10.1034/j.1399-0039.2001.057004339.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Direct automated DNA sequencing was used to analyze exons 2 and 3 of HLA-B alleles present in forty-four unrelated individuals residing in the village of Adiopodoume, Côte d'Ivoire (Ivory Coast). Of the 23 HLA-B alleles observed, the most frequently detected allele was HLA-B*5301 (22.7%), which is believed to confer resistance to severe Plasmodium falciparum malaria. B*4501 (9.1%), B*1503 (8.0%), B*0705 (5.7%), B*1510 (5.7%) and B*3501 (5.7%) occurred frequently in the population. A second allele of B53 was identified; B*5302 contains a single amino acid variation at residue 171 (Y-->H). Two additional novel alleles, B* 1405 (a single amino acid variant of B*1402) and B*4410 (a five amino acid variant of B*4403) were characterized.
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Affiliation(s)
- J M Ellis
- Department of Microbiology and Immunology, Georgetown University Medical Center, Washington, DC, USA
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5
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Quakyi IA, Ndoutse L, Ngu J, Lohoue J, Fogako J, Befidi-Mengue R, Harun LT, Eno A, Walker-Abbey A, Folefack A, Alake G, Taylor DW, Tchinda V, Megnekou R, Ndountse L, Tietche F, Wansi E, Leke RG, Titanji V, Leke R, Sama G, Manga L, Johnson AH, Mvondo JL, Nyonglema P, Djokam R, Bomba-Nkolo C, Tsafack M, Hickey MA, Bigoga J, Bomba-Nkolo D, Kouontchou S, Meli J, Njeungue E, Metenou S, Same-Ekobo A. The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa. Am J Trop Med Hyg 2000. [DOI: 10.4269/ajtmh.2000.63.222] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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6
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Quakyi IA, Leke RG, Befidi-Mengue R, Tsafack M, Bomba-Nkolo D, Manga L, Tchinda V, Njeungue E, Kouontchou S, Fogako J, Nyonglema P, Harun LT, Djokam R, Sama G, Eno A, Megnekou R, Metenou S, Ndountse L, Same-Ekobo A, Alake G, Meli J, Ngu J, Tietche F, Lohoue J, Mvondo JL, Wansi E, Leke R, Folefack A, Bigoga J, Bomba-Nkolo C, Titanji V, Walker-Abbey A, Hickey MA, Johnson AH, Taylor DW, Ndoutse L. The epidemiology of Plasmodium falciparum malaria in two Cameroonian villages: Simbok and Etoa. Am J Trop Med Hyg 2000; 63:222-30. [PMID: 11421368] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023] Open
Abstract
In support of ongoing immunologic studies on immunity to Plasmodium falciparum, demographic, entomologic, parasitologic, and clinical studies were conducted in two Cameroonian villages located 3 km apart. Simbok (population = 907) has pools of water present year round that provide breeding sites for Anopheles gambiae, whereas Etoa (population = 485) has swampy areas that dry up annually in which A. funestus breed. Results showed that individuals in Simbok receive an estimated 1.9 and 1.2 infectious bites per night in the wet and dry season, respectively, whereas individuals in Etoa receive 2.4 and 0.4 infectious bites per night, respectively. Although transmission patterns differ, the rate of acquisition of immunity to malaria appears to be similar in both villages. A prevalence of 50-75% was found in children < 10 years old, variable levels in children 11-15 years old, and 31% in adults. Thus, as reported in other parts of Africa, individuals exposed to continuous transmission of P. falciparum slowly acquired significant, but not complete, immunity.
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Affiliation(s)
- I A Quakyi
- Department of Biology, Reiss Science Center, Georgetown University, Washington, District of Columbia 20057, USA
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7
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Parra M, Hui G, Johnson AH, Berzofsky JA, Roberts T, Quakyi IA, Taylor DW. Characterization of conserved T- and B-cell epitopes in Plasmodium falciparum major merozoite surface protein 1. Infect Immun 2000; 68:2685-91. [PMID: 10768960 PMCID: PMC97475 DOI: 10.1128/iai.68.5.2685-2691.2000] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [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] [Indexed: 11/20/2022] Open
Abstract
Vaccines for P. falciparum will need to contain both T- and B-cell epitopes. Conserved epitopes are the most desirable, but they are often poorly immunogenic. The major merozoite surface protein 1 (MSP-1) is currently a leading vaccine candidate antigen. In this study, six peptides from conserved or partly conserved regions of MSP-1 were evaluated for immunogenicity in B10 congenic mice. Following immunization with the peptides, murine T cells were tested for the ability to proliferate in vitro and antibody responses to MSP-1 were evaluated in vivo. The results showed that one highly conserved sequence (MSP-1#1, VTHESYQELVKKLEALEDAV; located at amino acid positions 20 to 39) and one partly conserved sequence (MSP-1#23, GLFHKEKMILNEEEITTKGA; located at positions 44 to 63) contained both T- and B-cell epitopes. Immunization of mice with these peptides resulted in T-cell proliferation and enhanced production of antibody to MSP-1 upon exposure to merozoites. MSP-1#1 stimulated T-cell responses in three of the six strains of mice evaluated, whereas MSP-1#23 was immunogenic in only one strain. Immunization with the other four peptides resulted in T-cell responses to the peptides, but none of the resulting peptide-specific T cells recognized native MSP-1. These results demonstrate that two sequences located in the N terminus of MSP-1 can induce T- and B-cell responses following immunization in a murine model. Clearly, these sequences merit further consideration for inclusion in a vaccine for malaria.
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Affiliation(s)
- M Parra
- Departments of Biology, Georgetown University, Washington, DC 20057, USA.
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8
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Johnson A, Leke R, Harun L, Ginsberg C, Ngogang J, Stowers A, Saul A, Quakyi IA. Interaction of HLA and age on levels of antibody to Plasmodium falciparum rhoptry-associated proteins 1 and 2. Infect Immun 2000; 68:2231-6. [PMID: 10722624 PMCID: PMC97408 DOI: 10.1128/iai.68.4.2231-2236.2000] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [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] [Indexed: 11/20/2022] Open
Abstract
The Plasmodium falciparum rhoptry-associated proteins 1 and 2 (RAP1 and RAP2) are candidate antigens for a subunit malaria vaccine. The design of the study, which looks at the acquisition of immunity to malaria from childhood to old age, has allowed us to document the interaction of HLA and age on levels of antibody to specific malarial antigens. Antibodies reach maximum levels to RAP1 after the age of 15 but to RAP2 only after the age of 30. The effect of HLA-DRB1 and -DQB1 and age on levels of antibody to rRAP1 and rRAP2 was analyzed with a multiple regression model in which all HLA alleles and age were independent variables. DQB1*0301 and -*03032 showed an age-dependent association with levels of antibody to rRAP1, being significant in children 5 to 15 years (P < 0.001) but not in individuals over 15 years of age. DRB1*03011 showed an age-dependent association with antibody levels to rRAP2; however, this association was in adults over the age of 30 years (P < 0.01) but not in individuals under the age of 30 years. No associations were detected between DRB1 alleles and RAP1 antibody levels or between DQB1 alleles and RAP2 antibody levels. Thus, not only the HLA allele but also the age at which an interaction is manifested varies for different malarial antigens. The interaction may influence either the rate of acquisition of antibody or the final level of antibody acquired by adults.
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Affiliation(s)
- A Johnson
- Pediatrics, Georgetown University, Washington, D.C., USA.
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9
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Quakyi IA, Miller LH, Good MF, Ahlers JD, Isaacs SN, Nunberg JH, Houghten RA, Keister DB, Coligan JE, Moss B. Synthetic peptides from P. falciparum sexual stage 25-kDa protein induce antibodies that react with the native protein: the role of IL-2 and conformational structure on immunogenicity of Pfs25. Pept Res 1995; 8:335-44. [PMID: 8838417] [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] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
To identify B-cell epitopes of the Plasmodium falciparum 25-kDa ookinete protein, Pfs25, 41 overlapping synthetic peptides spanning the entire length of the protein were used individually to immunize CAF1 (F1 hybrid of BALB/c female and A/J male) mice. Antipeptide sera were tested for reactivity to live intact zygote/early ookinete (post-fertilization stage) by immunofluorescence, and by Western blot analysis under nonreducing and reducing conditions, immunoprecipitation of 35S-cysteine-labeled antigen, and ELISA using a vaccinia recombinant Pfs25 antigen. Fourteen B-cell epitopes were identified. These peptides were immunogenic only when administered with high-dose recombinant interleukin-2. Antibodies to 11 peptides recognized only the native conformational structure, one peptide induced antibodies that recognized both reduced and native protein, and two other peptides, after primary immunization, made antibodies to denatured Pfs25, but after boosting the antibodies reacted to both denatured and native Pfs25. Anti-sera to peptides in the first (peptide 7) and fourth (peptide 34) epidermal growth factor-like domains of Pfs25 reacted most strongly with zygotes/ookinetes by immunofluorescence assay. The antibodies elicited by immunization with peptide 34 suppressed infectivity of the parasite to mosquitoes. We further observed that the secondary structure of Pfs25 may be important for immunogenicity because monoclonal antibodies (MAbs) 1C7 and 1D2, both transmission-blocking MAbs, protected enzyme cleavage sites in Pfs25 from proteolysis, suggesting that discontinuous segments of Pfs25 may come together to form immunogenic epitopic sites. Thus, definition of B- and T-cell epitopes may be required to construct a Pfs25 vaccine for optimum immunogenicity.
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Affiliation(s)
- I A Quakyi
- Georgetown University, Washington, DC, USA
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10
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. The Journal of Immunology 1994. [DOI: 10.4049/jimmunol.153.5.2082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J Currier
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - A Fell
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - D W Taylor
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - T Roberts
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R A Houghten
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - R D England
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - J A Berzofsky
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - L H Miller
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
| | - M F Good
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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11
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Quakyi IA, Currier J, Fell A, Taylor DW, Roberts T, Houghten RA, England RD, Berzofsky JA, Miller LH, Good MF. Analysis of human T cell clones specific for conserved peptide sequences within malaria proteins. Paucity of clones responsive to intact parasites. J Immunol 1994; 153:2082-92. [PMID: 8051413] [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] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
T cells are thought to be of central importance in malaria immunity. Peptides copying malaria protein sequences often stimulate human CD4+ T cells and it was thought that they represented T cell epitopes present in the parasite and may thus have particular relevance to malaria vaccine development. To verify whether synthetic peptides representing highly conserved regions of parasite Ags may contribute to a malaria vaccine, we searched the data bank for conserved regions of Plasmodium falciparum malaria proteins that were not homologous to known self (human) proteins. We synthesized 24 such peptides representing 11 of the cloned and sequenced malaria asexual stage Ags, which were predicted by algorithms to represent T cell epitopes, and 6 peptides not predicted to be T cell epitopes and used these to generate T cell clones from individuals with an extensive previous history of malaria exposure. The T cell clones responded vigorously to many peptides but only a single clone, specific for a peptide within merozoite surface protein-1, 20-39, VTHESYQELVKKLEALEDAV, and not previously defined to be a T cell epitope responded to malaria parasites by proliferation and secretion of IFN-gamma. This epitope was not revealed by studying parasite-induced T cell lines and is thus subdominant. The clone was able to significantly inhibit parasite growth in vitro. The final step in the inhibition of parasite growth appears to be nonspecific because other activated clones (not specific for malaria sequences) can inhibit parasite growth. Our data suggest that few conserved peptides within malaria parasites can be processed from the intact parasite. However, such peptides that can be processed from malaria parasites may be expected to stimulate parasite-specific T cells that could inhibit parasite growth and as such may be lead candidates for a vaccine aimed at inducing cellular immunity to malaria.
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Affiliation(s)
- I A Quakyi
- Malaria and Arbovirus Unit, Queensland Institute of Medical Research, Brisbane, Australia
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12
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Quakyi IA, Taylor DW, Johnson AH, Allotey JB, Berzofsky JA, Miller LH, Good MF. Development of a malaria T-cell vaccine for blood stage immunity. Scand J Immunol Suppl 1992; 11:9-16. [PMID: 1381110 DOI: 10.1111/j.1365-3083.1992.tb01611.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We have defined a strategy for the development of a T-cell vaccine for blood stage immunity, taking into consideration the central role of T cells and MHC restriction in malaria immune responses. We have used the AMPHI computer algorithm to identify putative T-cell epitopes from conserved regions of 11 Plasmodium falciparum asexual stage proteins. Ten of the eleven proteins are currently candidates for vaccine development. Using this algorithm we selected 22 putative T-cell epitope peptides and 8 control peptides. These peptides were used to test the T-cell responses of three defined populations of Caucasians who have (1) recovered from P. falciparum malaria, (2) been exposed, but never clinically infected, (3) never been exposed or infected. Preliminary analysis of our data shows population differences in T-cell responses to putative T-cell epitope peptides. Ultimately, these studies will help to identify those T epitopes that can be incorporated into a T-cell vaccine for protective immunity.
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Affiliation(s)
- I A Quakyi
- Department of Biology, Georgetown University, Washington DC 20057-1028
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13
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Leke RG, Ndansi R, Southerland NJ, Quakyi IA, Taylor DW. Identification of anti-Plasmodium falciparum antibodies in human breast milk. Scand J Immunol Suppl 1992; 11:17-22. [PMID: 1514035 DOI: 10.1111/j.1365-3083.1992.tb01612.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Malarial infections are rarely observed in neonates. It has been postulated that some immunity may be passively transferred during nursing, but anti-malarial antibodies (Abs) have not been detected in human milk. In this study, milk samples, collected 2-14 days after parturition from women at the Central Maternity Hospital, Yaounde, were evaluated for total IgG and IgA antibody levels by radial diffusion, protein composition by SDS-PAGE, anti-malarial antibodies using an isotype-specific immunofluorescence assay, and the ability to immunoprecipitate Plasmodium falciparum antigens metabolically labelled with 35S-methionine. Results showed that anti-P. falciparum antibodies were present in breast milk, and that paired milk and serum samples from individual women contained Abs that recognized similar malarial antigens.
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Affiliation(s)
- R G Leke
- University Centre for Health Sciences, University of Yaounde, Cameroun
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14
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Barr PJ, Green KM, Gibson HL, Bathurst IC, Quakyi IA, Kaslow DC. Recombinant Pfs25 protein of Plasmodium falciparum elicits malaria transmission-blocking immunity in experimental animals. J Exp Med 1991; 174:1203-8. [PMID: 1940798 PMCID: PMC2118997 DOI: 10.1084/jem.174.5.1203] [Citation(s) in RCA: 169] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Pfs25 is a sexual stage antigen of Plasmodium falciparum that is expressed on the surface of zygote and ookinete forms of the parasite. Monoclonal antibodies directed against native Pfs25 can block completely the development of P. falciparum oocysts in the midgut of the mosquito vector. Thus, this 25-kD protein is a potential vaccine candidate for eliciting transmission-blocking immunity in inhabitants of malaria endemic regions. We have synthesized, by secretion from yeast, a polypeptide analogue of Pfs25 that reacts with conformation-dependent monoclonal antibodies, and elicits transmission-blocking antibodies when used to immunize mice and monkeys in conjunction with a muramyl tripeptide adjuvant. Our results suggest the further evaluation of recombinant DNA-derived Pfs25 in transmission-blocking vaccination studies in humans.
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Affiliation(s)
- P J Barr
- Chiron Corporation, Emeryville, California 94608
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15
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Rodriguez-del Valle M, Quakyi IA, Amuesi J, Quaye JT, Nkrumah FK, Taylor DW. Detection of antigens and antibodies in the urine of humans with Plasmodium falciparum malaria. J Clin Microbiol 1991; 29:1236-42. [PMID: 1864942 PMCID: PMC269976 DOI: 10.1128/jcm.29.6.1236-1242.1991] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Humans infected with Plasmodium falciparum frequently have elevated levels of proteins in their urine, but it is unclear if any of these proteins are parasite antigens or antimalarial antibodies. To resolve this question, urine samples from malaria patients and controls living in Thailand and Ghana were evaluated. Urine samples from 85% of the patients had elevated protein levels and contained proteins with Mrs ranging from less than 29,000 to greater than 224,000 as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Antisera were produced against urine from infected and control subjects. Antisera raised against infected, but not control, urine were positive by indirect immunofluorescence on P. falciparum parasites and immunoprecipitated approximately 12 unique bands from extracts of parasites metabolically labeled with 35S-methionine. These data suggest that a variety of P. falciparum antigens are released into urine during acute infection. It is also likely that anti-P. falciparum antibodies are present in the urine of malaria patients because samples from these patients, but not controls, were positive in indirect immunofluorescence assays and immunoprecipitated at least 19 P. falciparum antigens from extracts of metabolically labeled parasites. The detection of malarial antigens and antibodies in urine may lead to a new approach for the diagnosis of malaria.
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16
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Kaslow DC, Isaacs SN, Quakyi IA, Gwadz RW, Moss B, Keister DB. Induction of Plasmodium falciparum transmission-blocking antibodies by recombinant vaccinia virus. Science 1991; 252:1310-3. [PMID: 1925544 DOI: 10.1126/science.1925544] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Many candidate antigens of malaria vaccines have limited immunological recognition. One exception is Pfs25, a cysteine-rich, 25-kilodalton sexual stage surface protein of Plasmodium falciparum. Pfs25 is a target of monoclonal antibodies that block transmission of malaria from vertebrate host to mosquito vector. The surface of mammalian cells infected with a recombinant vaccinia virus that expressed Pfs25 specifically bound transmission-blocking monoclonal antibodies. Furthermore, major histocompatibility complex-disparate congenic mouse strains immunized with recombinant Pfs25 elicited transmission-blocking antibodies, demonstrating that the capacity to develop transmission-blocking antibodies is not genetically restricted in mice. Live recombinant viruses may provide an inexpensive, easily administered alternative to subunit vaccines prepared from purified recombinant proteins to block transmission of malaria in developing countries.
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Affiliation(s)
- D C Kaslow
- Malaria Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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17
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Carter R, Graves PM, Keister DB, Quakyi IA. Properties of epitopes of Pfs 48/45, a target of transmission blocking monoclonal antibodies, on gametes of different isolates of Plasmodium falciparum. Parasite Immunol 1990; 12:587-603. [PMID: 1707506 DOI: 10.1111/j.1365-3024.1990.tb00990.x] [Citation(s) in RCA: 96] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
We have studied the properties of epitopes on Plasmodium falciparum gamete surface protein Pfs 48/45, a target antigen of malaria transmission blocking antibodies. Using a two site immunoradiometric assay we have defined three spacially separate, non-repeated, epitope regions on the peptides representing this antigen. Epitope region I is a target of monoclonal antibodies (MoAbs) which strongly suppress infectivity of gametocytes of P. falciparum to mosquitoes; the effect is complement independent and is mediated as effectively by the monovalent Fab fragments as by intact MoAb. Epitope region II consists of two spacially close subregions, IIa and IIb; variant forms of epitopes IIa and IIb occurred in different isolates of P. falciparum. Epitope region III also showed slight structural modification between isolates. MoAbs against regions II or III were relatively ineffective in suppressing gametocyte infectivity compared to MoAbs against region I. However, certain combinations of MoAbs against regions II and III together acted synergistically to suppress infectivity to mosquitoes. All these epitopes failed to react with MoAb when the antigen was presented in reduced form. A fourth epitope, however, was identified which reacted strongly with MoAb when the antigen was presented in reduced form. The MoAb against this epitope had no effect on the infectivity of gametocytes of P. falciparum to mosquitoes.
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Affiliation(s)
- R Carter
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892
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18
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Good MF, Kumar S, De Groot AS, Weiss WR, Quakyi IA, Dontfraid F, Smith GE, Cochran M, Berzofsky JA, Miller LH. Evidence implicating MHC genes in the immunological nonresponsiveness to the Plasmodium falciparum CS protein. Bull World Health Organ 1990; 68 Suppl:80-4. [PMID: 1709836 PMCID: PMC2393035] [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] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The circumsporozoite (CS) protein is a major candidate vaccine antigen for the sporozoite stage of malaria. Both cytotoxic T cells (CTL) and antibody specific for the CS protein are thought to be important in protection. By examining the immune response in mice and humans we have shown that genes mapping to the major histocompatibility complex (MHC) are important for immune responsiveness. F1 mice between high antibody responders and low antibody responders are high antibody responders, suggesting that in this model immune suppressor genes do not control the immune response. Using synthetic peptides to map epitopes for CTL and helper T cells (which are important for the antibody response) we have shown that the T-cell epitopes are located in the polymorphic region of the protein, and we hypothesize that T cells have indeed selected the variation observed in the CS protein. The success of subunit vaccines will depend on the pattern of variation in different geographical locations, the ability to construct multivalent vaccines containing different variant epitopes from this protein, and on the existence of other sporozoite and liver-stage proteins involved in protection.
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Affiliation(s)
- M F Good
- Laboratory of Parasitic Diseases, N.I.A.I.D., National Institutes of Health, Bethesda, MD
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19
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Quakyi IA, Otoo LN, Pombo D, Sugars LY, Menon A, De Groot AS, Johnson A, Alling D, Miller LH, Good MF. Differential non-responsiveness in humans of candidate Plasmodium falciparum vaccine antigens. Am J Trop Med Hyg 1989; 41:125-34. [PMID: 2672834] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Synthetic subunit vaccines to sporozoites, merozoites, and gametes are being developed for malaria. The vaccine strategy assumes that the population to be immunized will respond favorably to these vaccine antigens. Using sera of 35 adults and 50 children from the The Gambia, West Africa, where Plasmodium falciparum is highly endemic, we examined the humoral immune response to candidate malaria vaccine antigens from sporozoites, merozoites, and gametes. We observed widespread restricted immunogenicity to defined parasite antigens in children and adults. HLA typing of adult lymphocytes demonstrated a marked diversity in HLA haplotypes in this population. Our results and those from our studies in mice suggest that genetic factors may partly explain the immunological non-responsiveness. This may necessitate re-evaluation of the malaria vaccine strategy.
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Affiliation(s)
- I A Quakyi
- National Institutes of Health, Bethesda, Maryland
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20
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de Groot AS, Johnson AH, Maloy WL, Quakyi IA, Riley EM, Menon A, Banks SM, Berzofsky JA, Good MF. Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein. The Journal of Immunology 1989. [DOI: 10.4049/jimmunol.142.11.4000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.
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Affiliation(s)
- A S de Groot
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - A H Johnson
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - W L Maloy
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - I A Quakyi
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - E M Riley
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - A Menon
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - S M Banks
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - J A Berzofsky
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
| | - M F Good
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
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21
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de Groot AS, Johnson AH, Maloy WL, Quakyi IA, Riley EM, Menon A, Banks SM, Berzofsky JA, Good MF. Human T cell recognition of polymorphic epitopes from malaria circumsporozoite protein. J Immunol 1989; 142:4000-5. [PMID: 2469729] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lymphocytes obtained from forty individuals living in a malaria endemic area of West Africa were tested for in vitro proliferative responses to peptides representing variant regions of the immunodominant T cell domain of the circumsporozoite protein (amino acids 326 to 345, referred to as Th2R, and 361 to 380, referred to as Th3R) from three distinct strains of Plasmodium falciparum. A total of 83% of the individuals responded to at least one of the six peptides tested, confirming that these epitopes are immunodominant. A much greater number of individuals than expected by chance (32% of the responders to Th2R and 27% of the responders to Th3R) reacted to all three of the variant peptides for that epitope, indicating interdependency of the T cell responses, suggestive of cross-reactivity. Nevertheless, some subjects' T cells were clearly able to distinguish each variant peptide from the others. Using EBV transformed B cells, lymphocytes from 10 of the individuals were HLA typed. In this small group, HLA DRw13 was associated with a positive response to any of the peptides, whereas there was a negative association between DQw3 and response to any of the peptides. These results, although limited by the small sample size, suggest that recognition of T epitopes may be Ir gene linked. Our findings suggest that it may be possible to broaden the immunogenicity of an anti-sporozoite malaria vaccine.
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Affiliation(s)
- A S de Groot
- Laboratory of Parasitic Diseases, National Institutes of Allergy and Infectious Disease, Bethesda, MD 20892
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22
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Quakyi IA, Matsumoto Y, Carter R, Udomsangpetch R, Sjolander A, Berzins K, Perlmann P, Aikawa M, Miller LH. Movement of a falciparum malaria protein through the erythrocyte cytoplasm to the erythrocyte membrane is associated with lysis of the erythrocyte and release of gametes. Infect Immun 1989; 57:833-9. [PMID: 2645212 PMCID: PMC313185 DOI: 10.1128/iai.57.3.833-839.1989] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [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] [Indexed: 01/01/2023] Open
Abstract
Erythrocytes containing mature gametocytes of Plasmodium falciparum circulate in the blood until they are ingested by a mosquito, an event that triggers gametogenesis and lysis of the infected erythrocyte. It was previously shown that a parasite protein (Pf155/RESA) accumulates in the erythrocyte cytoplasm next to the parasitophorous vacuolar membrane (S. Uni, A. Masuda, M. J. Stewart, R. Nussenzweig, and M. Aikawa, Am. J. Trop. Med. Hyg., 36:481-488, 1987). Using a monoclonal antibody to Pf155/RESA and rabbit sera to two different repeat peptides of Pf155/RESA, we have studied the location of Pf155/RESA after induction of gametogenesis. Five minutes after triggering gametogenesis, the parasitophorous membrane no longer surrounded the parasite, bringing the parasite membrane in contact with the erythrocyte cytoplasm. Clear spaces appeared throughout the hemoglobin-rich host cytoplasm; Pf155/RESA was now localized in the cytoplasm directly surrounding the spaces. No membrane existed between the spaces and the erythrocyte cytoplasm. The spaces with surrounding Pf155/RESA protein extended to the erythrocyte membrane. After lysis of the erythrocyte membrane (15 min after triggering gametogenesis), the protein was distributed along the erythrocyte membrane and throughout the space between the gamete and the erythrocyte membrane. The mechanism by which Pf155/RESA remained aggregated around the spaces and its role in erythrocyte lysis are unknown. It is of interest that the parasite appeared to use the same molecule during invasion of erythrocytes and during release of gametes from infected erythrocytes.
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Affiliation(s)
- I A Quakyi
- Malaria Section, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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23
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Affiliation(s)
- D C Kaslow
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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24
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Carter R, Graves PM, Quakyi IA, Good MF. Restricted or absent immune responses in human populations to Plasmodium falciparum gamete antigens that are targets of malaria transmission-blocking antibodies. J Exp Med 1989; 169:135-47. [PMID: 2642527 PMCID: PMC2189199 DOI: 10.1084/jem.169.1.135] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
We have studied the antibodies to sexual stage antigens of Plasmodium falciparum in human sera from Papua New Guinea where intense transmission of P. falciparum occurs as well as the less prevalent P. malariae and P. vivax. In extracts of gametes of P. falciparum we have studied the reactivity of serum antibodies with antigens labeled with 125I on the surface of the gametes as well as intracellular gamete antigens. A prominent 27-kD sexual stage-specific intracellular protein was recognized more or less in proportion to the general antibody response to gamete proteins. The response to the gamete surface proteins, however, was quite unrepresentative of the general antibody response to the intracellular gamete proteins. No antibodies were detected against Pfs25, a 21-kD protein expressed on zygotes and ookinetes of P. falciparum and known to be a sensitive target of malaria transmission-blocking antibodies. The antibody response to two other target antigens of transmission-blocking antibodies on the surface of gametes of P. falciparum, a 230- and a 48- and 45-kD protein doublet, was very variable and independent of the response to the internal protein antigens. Several possibilities are discussed that may account for the variable response to these gamete surface antigens in individuals with otherwise good antibody responses to internal sexual stage proteins. Among these is the possibility that there is MHC restriction of the immune response to the gamete surface antigens in the human population. This interpretation accords well with evidence for MHC-restricted immune response to the same P. falciparum gamete surface antigens in studies with H-2 congenic mice (24).
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Affiliation(s)
- R Carter
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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25
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Dontfraid F, Cochran MA, Pombo D, Knell JD, Quakyi IA, Kumar S, Houghten RA, Berzofsky JA, Miller LH, Good MF. Human and murine CD4 T cell epitopes map to the same region of the malaria circumsporozoite protein: limited immunogenicity of sporozoites and circumsporozoite protein. Mol Biol Med 1988; 5:185-96. [PMID: 2468986] [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] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The circumsporozoite (CS) protein is a candidate vaccine antigen for the sporozoite stage in the life cycle of the malaria parasite. Using CS protein purified from recombinant baculovirus-infected cells and a panel of H-2 congenic mice, we are able to demonstrate that this protein is poorly immunogenic in terms of antibody production as a result of Ir gene control. The immune response to the protein is also restricted following immunization with a CS-recombinant vaccinia virus or with sporozoites. Using a panel of overlapping peptides spanning the entire protein, we are able to show that the high responder mice recognize helper T cell epitopes from the same region of the protein as do humans. This region, however, is the polymorphic segment of the protein, which has implications for vaccine development. However, the close overlap of human and murine T cell epitopes demonstrates that murine models may be very useful in epitope mapping and vaccine development for human pathogens. The T cell antigenic regions of this protein fulfil the predictive requirements for the amphipathic helicity algorithm.
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Affiliation(s)
- F Dontfraid
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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26
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Good MF, Miller LH, Kumar S, Quakyi IA, Keister D, Adams JH, Moss B, Berzofsky JA, Carter R. Limited immunological recognition of critical malaria vaccine candidate antigens. Science 1988; 242:574-7. [PMID: 2902690 DOI: 10.1126/science.2902690] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Current vaccine development strategies for malaria depend on widespread immunological responsiveness to candidate antigens such as the zygote surface antigens and the sporozoite coat protein, the circumsporozoite (CS) protein. Since immunological responsiveness is controlled mainly by genes mapping within the major histocompatibility complex (MHC), the humoral immune response to the zygote surface antigens and the cytotoxic T lymphocyte (CTL) response to the CS protein were examined in MHC-disparate congenic mouse strains. Only two of six strains responded to the 230-kilodalton zygote surface antigen and another two strains responded to the 48/45-kilodalton surface antigen. From two mouse strains, expressing between them five different class I MHC molecules, there was recognition of only a single CTL epitope from the CS protein, which was from a polymorphic segment of the molecule. The restricted CTL response to this protein parallels the restricted antibody response to this protein observed in humans and mice. These findings suggest that subunit malaria vaccines now being developed may be ineffective.
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Affiliation(s)
- M F Good
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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27
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Kumar S, Miller LH, Quakyi IA, Keister DB, Houghten RA, Maloy WL, Moss B, Berzofsky JA, Good MF. Cytotoxic T cells specific for the circumsporozoite protein of Plasmodium falciparum. Nature 1988; 334:258-60. [PMID: 2456467 DOI: 10.1038/334258a0] [Citation(s) in RCA: 149] [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] [Indexed: 01/01/2023]
Abstract
Malaria is initiated by the inoculation of a susceptible host with sporozoites from an infected mosquito. The sporozoites enter hepatocytes and develop for a period as exoerythrocyte or hepatic stage parasites. Vaccination with irradiated sporozoites can provide protective immunity and a recent study shows that this can also be conferred by immunization with a recombinant salmonella expressing only the circumsporozoite protein that normally covers the sporozoites. Protection against infection is likely to be mediated by cytotoxic CD8+ cells, as depletion of CD8+ T cells in a sporozoite-immunized animal can completely abrogate immunity. Here we demonstrate directly the existence of CD8+ cytotoxic T lymphocytes (CTL) that recognize the circumsporozoite protein. B10.BR mice immunized with sporozoites or with recombinant vaccinia virus expressing the CS protein of Plasmodium falciparum contain CTL that specifically kill L cell fibroblasts transfected with the gene encoding the same CS protein. The peptide epitope from the CS protein that is recognized by CTL from this strain of mice is from a variant region of the protein.
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Affiliation(s)
- S Kumar
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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28
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Kaslow DC, Quakyi IA, Syin C, Raum MG, Keister DB, Coligan JE, McCutchan TF, Miller LH. A vaccine candidate from the sexual stage of human malaria that contains EGF-like domains. Nature 1988; 333:74-6. [PMID: 3283563 DOI: 10.1038/333074a0] [Citation(s) in RCA: 315] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Malaria vaccines are being developed against different stages in the parasite's life cycle, each increasing the opportunity to control malaria in its diverse settings. Sporozoite vaccines are designed to prevent mosquito-induced infection; first generation recombinant or synthetic peptide vaccines have been tested in humans. Asexual erythrocytic stage vaccines, developed to prevent or reduce the severity of disease, have been tested in animals and in humans. A third strategy is to produce sexual stage vaccines that would induce antibodies which would prevent infection of mosquitoes when ingested in a bloodmeal containing sexual stage parasites. Although not directly protective, the sexual stage vaccine combined with a sporozoite or asexual stage vaccine (protective component) could prolong the useful life of the protective component by reducing transmission of resistant vaccine-induced mutants. In areas of low endemnicity, the sexual stage vaccine could reduce transmission below the critical threshold required to maintain the infected population, thereby assisting in the control or eradication of malaria. Transmission of Plasmodium falciparum, the major human malaria, can be blocked by monoclonal antibodies against three sexual stage-specific antigens. We have cloned the gene encoding the surface protein of relative molecular mass Mr 25,000 (25K; Pfs25), expressed on zygotes and ookinetes of P. falciparum. The deduced amino-acid sequence consists of a signal sequence, a hydrophobic C-terminus, and four tandem epidermal growth factor EGF-like domains.
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Affiliation(s)
- D C Kaslow
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, Maryland 20892
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29
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Abstract
Sera from individuals living in malaria endemic areas of Papua New Guinea were tested for their effect on infectivity of Plasmodium falciparum gametocytes grown in culture to Anopheles freeborni mosquitoes. Consistent reduction of infectivity to less than 5% of control was observed with nine out of the 41 sera from the endemic area tested and also with three out of seven sera tested from individuals rarely exposed to malaria infection. Gamete surface antigens recognized by the sera were investigated by immunoprecipitation from 125I surface-labelled gametes extracted in SDS and Triton X-100. The main antigens recognized were of the same mol. wt (230, 48 and 45 kD) as those known to be targets of transmission-blocking monoclonal antibodies. A significant negative correlation was observed between the total ct/min immunoprecipitated from surface-labelled gametes by the sera and the average number of oocysts per gut observed in membrane feeding experiments with these sera. Spearmann's rank correlation coefficient indicated that suppression of infectivity correlated strongly with the presence of antibodies against the 230 kD protein; there was no significant correlation between suppression and antibodies to the 48/45 kD proteins. The antibody response to the different gamete surface antigens varied greatly in sera from the endemic areas suggesting that individuals respond differently to each gamete antigen.
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Affiliation(s)
- P M Graves
- Papua New Guinea Institute of Medical Research, Madang
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30
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Good MF, Pombo D, Quakyi IA, Riley EM, Houghten RA, Menon A, Alling DW, Berzofsky JA, Miller LH. Human T-cell recognition of the circumsporozoite protein of Plasmodium falciparum: immunodominant T-cell domains map to the polymorphic regions of the molecule. Proc Natl Acad Sci U S A 1988; 85:1199-203. [PMID: 2448793 PMCID: PMC279734 DOI: 10.1073/pnas.85.4.1199] [Citation(s) in RCA: 181] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
The definition of human T-cell antigenic sites is important for subunit vaccine development of a peptide immunogen if the goal is to allow antibody boosting during infection or to stimulate antibody-independent T-cell immunity. To identify such sites on the circumsporozoite (CS) protein of Plasmodium falciparum, 29 overlapping synthetic peptides spanning the entire CS protein were made and tested for their ability to stimulate peripheral blood lymphocytes from 35 adults living in a P. falciparum malaria-endemic region of West Africa. Three immunodominant domains were located outside the repetitive region. These domains, however, occurred in the polymorphic regions of the molecule, suggesting that parasite mutation and selection has occurred in response to immune pressure from T cells. Such polymorphism may impose an obstacle for vaccine development.
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Affiliation(s)
- M F Good
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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31
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Szarfman A, Walliker D, McBride JS, Lyon JA, Quakyi IA, Carter R. Allelic forms of gp195, a major blood-stage antigen of Plasmodium falciparum, are expressed in liver stages. J Exp Med 1988; 167:231-6. [PMID: 3275737 PMCID: PMC2188805 DOI: 10.1084/jem.167.1.231] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Mature exoerythrocytic (EE) forms of two cloned lines (3D7 and HB3) of Plasmodium falciparum were obtained in the livers of splenectomized chimpanzees. Sectioned preparations were examined by immunofluorescence (IFA) using mAbs that distinguished allelic variants of the blood-form antigen gp195 and mAbs that recognized multiple conserved epitopes of gp195. EE forms and blood schizonts exhibited identical IFA reactions for each respective clone, showing that the antigen was expressed identically in liver and blood-stage parasites. A third chimpanzee was infected with sporozoites derived from a mixture of 3D7 and HB3 gametocytes that had undergone cross-fertilization in the mosquitoes. IFAs on the EE forms in this animal showed that segregation of each gp195 allele had occurred earlier in the life cycle, providing evidence that the parasite is haploid for the whole of its mammalian development.
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Affiliation(s)
- A Szarfman
- Infectious Diseases Department, Naval Medical Research Institute, Bethesda, Maryland
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Quakyi IA, Carter R, Rener J, Kumar N, Good MF, Miller LH. The 230-kDa gamete surface protein of Plasmodium falciparum is also a target for transmission-blocking antibodies. J Immunol 1987; 139:4213-7. [PMID: 2447164] [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] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Immunization with extracellular sexual stages of the malaria parasites can induce the production of antibodies which block the development of the parasites in the midgut of a mosquito after a blood meal. We have generated a number of monoclonal antibodies against gametes and zygotes of the human malaria Plasmodium falciparum. Two monoclonal antibodies (mAb) reacting with a 230-kDa gamete surface protein (mAb 1B3 and 2B4 both isotype IgG2a) were found to block transmission of P. falciparum to mosquitoes. Blocking was complement dependent and this was verified in vitro by the rapid lysis of newly formed gametes and zygotes in the presence of the mAb and active complement. Both mAb reacted by immunofluorescence with the surface of gametes and zygotes from isolates of P. falciparum from various geographical areas. Each mAb immunoprecipitated a 230-kDa protein from 125I-labeled surface proteins of newly formed gametes and zygotes and immunoblotted a protein doublet of about molecular mass 260 and 230 kDa from gametocytes and gametes of P. falciparum. Only the 230-kDa protein is expressed on the surface of newly formed macrogametes and zygotes. The 230-kDa gamete surface protein forms a molecular complex with two proteins of 48 and 45 kDa. The 48- and 45-kDa gamete surface proteins have previously been shown to be targets of mAb which block infectivity of P. falciparum to mosquitoes. The present study now demonstrates that antibodies against the 230-kDa gamete surface protein block transmission of P. falciparum to mosquitoes. The 230-kDa gamete protein is thus a potential candidate for a gamete vaccine.
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Affiliation(s)
- I A Quakyi
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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Quakyi IA, Carter R, Rener J, Kumar N, Good MF, Miller LH. The 230-kDa gamete surface protein of Plasmodium falciparum is also a target for transmission-blocking antibodies. The Journal of Immunology 1987. [DOI: 10.4049/jimmunol.139.12.4213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Immunization with extracellular sexual stages of the malaria parasites can induce the production of antibodies which block the development of the parasites in the midgut of a mosquito after a blood meal. We have generated a number of monoclonal antibodies against gametes and zygotes of the human malaria Plasmodium falciparum. Two monoclonal antibodies (mAb) reacting with a 230-kDa gamete surface protein (mAb 1B3 and 2B4 both isotype IgG2a) were found to block transmission of P. falciparum to mosquitoes. Blocking was complement dependent and this was verified in vitro by the rapid lysis of newly formed gametes and zygotes in the presence of the mAb and active complement. Both mAb reacted by immunofluorescence with the surface of gametes and zygotes from isolates of P. falciparum from various geographical areas. Each mAb immunoprecipitated a 230-kDa protein from 125I-labeled surface proteins of newly formed gametes and zygotes and immunoblotted a protein doublet of about molecular mass 260 and 230 kDa from gametocytes and gametes of P. falciparum. Only the 230-kDa protein is expressed on the surface of newly formed macrogametes and zygotes. The 230-kDa gamete surface protein forms a molecular complex with two proteins of 48 and 45 kDa. The 48- and 45-kDa gamete surface proteins have previously been shown to be targets of mAb which block infectivity of P. falciparum to mosquitoes. The present study now demonstrates that antibodies against the 230-kDa gamete surface protein block transmission of P. falciparum to mosquitoes. The 230-kDa gamete protein is thus a potential candidate for a gamete vaccine.
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Affiliation(s)
- I A Quakyi
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - R Carter
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - J Rener
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - N Kumar
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - M F Good
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
| | - L H Miller
- Laboratory of Parasitic Diseases, National Institute of Allergy and Infectious Diseases, Bethesda, MD 20892
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Walliker D, Quakyi IA, Wellems TE, McCutchan TF, Szarfman A, London WT, Corcoran LM, Burkot TR, Carter R. Genetic analysis of the human malaria parasite Plasmodium falciparum. Science 1987; 236:1661-6. [PMID: 3299700 DOI: 10.1126/science.3299700] [Citation(s) in RCA: 556] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Malaria parasites are haploid for most of their life cycle, with zygote formation and meiosis occurring during the mosquito phase of development. The parasites can be analyzed genetically by transmitting mixtures of cloned parasites through mosquitoes to permit cross-fertilization of gametes to occur. A cross was made between two clones of Plasmodium falciparum differing in enzymes, drug sensitivity, antigens, and chromosome patterns. Parasites showing recombination between the parent clone markers were detected at a high frequency. Novel forms of certain chromosomes, detected by pulsed-field gradient gel electrophoresis, were produced readily, showing that extensive rearrangements occur in the parasite genome after cross-fertilization. Since patients are frequently infected with mixtures of genetically distinct parasites, mosquito transmission is likely to provide the principal mechanisms for generating parasites with novel genotypes.
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Good MF, Quakyi IA, Saul A, Berzofsky JA, Carter R, Miller LH. Human T clones reactive to the sexual stages of Plasmodium falciparum malaria. High frequency of gamete-reactive T cells in peripheral blood from nonexposed donors. J Immunol 1987; 138:306-11. [PMID: 2431058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Malarial gametocytes, which are taken up by mosquitoes during a blood meal, develop in the gut of the mosquito into gametes. Gametes and gametocytes contain the target antigens of transmission-blocking immunity. Here, we show that the peripheral blood of nonexposed donors contains Plasmodium falciparum gamete-reactive T cells at frequencies ranging from 1/300 to 1/4000. Studies on long-term clones demonstrated that these cells often recognized antigens shared between gametes and asexual stage parasites or even between heterologous gametes, although it has been possible to derive a P. falciparum gamete-specific T clone. The T clones examined were T3+, T4+, T8-, and either HLA-DR- or HLA-DQ-restricted. They responded to gametes by both proliferation and the secretion of gamma-interferon. The gamete-specific clone and other asexual cross-reactive clones examined could be stimulated in vitro by a preparation of mature gametocytes within RBC, but not by RBC alone, suggesting that gametocytes are immunogenic or can become immunogenic for T cells in vivo. The significance of these observations to mosquito transmission of malaria and development and application of a gamete vaccine are discussed.
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Good MF, Quakyi IA, Saul A, Berzofsky JA, Carter R, Miller LH. Human T clones reactive to the sexual stages of Plasmodium falciparum malaria. High frequency of gamete-reactive T cells in peripheral blood from nonexposed donors. The Journal of Immunology 1987. [DOI: 10.4049/jimmunol.138.1.306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
Malarial gametocytes, which are taken up by mosquitoes during a blood meal, develop in the gut of the mosquito into gametes. Gametes and gametocytes contain the target antigens of transmission-blocking immunity. Here, we show that the peripheral blood of nonexposed donors contains Plasmodium falciparum gamete-reactive T cells at frequencies ranging from 1/300 to 1/4000. Studies on long-term clones demonstrated that these cells often recognized antigens shared between gametes and asexual stage parasites or even between heterologous gametes, although it has been possible to derive a P. falciparum gamete-specific T clone. The T clones examined were T3+, T4+, T8-, and either HLA-DR- or HLA-DQ-restricted. They responded to gametes by both proliferation and the secretion of gamma-interferon. The gamete-specific clone and other asexual cross-reactive clones examined could be stimulated in vitro by a preparation of mature gametocytes within RBC, but not by RBC alone, suggesting that gametocytes are immunogenic or can become immunogenic for T cells in vivo. The significance of these observations to mosquito transmission of malaria and development and application of a gamete vaccine are discussed.
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Sherwood JA, Spitalnik SL, Aley SB, Quakyi IA, Howard RJ. Plasmodium falciparum and P. knowlesi: initial identification and characterization of malaria synthesized glycolipids. Exp Parasitol 1986; 62:127-41. [PMID: 3522260 DOI: 10.1016/0014-4894(86)90016-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
This is the first report establishing the existence of glycolipids synthesized by plasmodia, in particular Plasmodium falciparum. Trophozoites, schizonts, gametocytes, and gametes were metabolically labeled in vitro with [3H]glucosamine, [3H]galactose, [3H]glucose, [3H]mannose, [3H]fucose, [32P]inorganic phosphate, or [35S]sulfate, and total lipid extracts analyzed by high-performance thin-layer chromatography and autoradiography or fluorography. Parasites incorporated [3H]monosaccharides into distinctly different series of molecules previously undescribed. Three properties of [3H]glucosamine labeled molecules indicate they are glycolipids. First, labeled molecules have lipid solubility properties. Second, mobility on thin-layer chromatography was characteristic of glycolipids. Third, following acid hydrolysis, [3H]glucosamine was recovered from a total lipid extract of labeled parasites demonstrating that glucosamine is a constituent of some of these lipid molecules. Most of these glycolipids are neutral and alkali labile. The majority of these glycolipids differs from several synthesized phospholipids. None of these glycolipids was sulfated. Plasmodial glycolipid synthesis occurs concomitantly with glycoprotein synthesis, and both increase during schizogony. Many of these glycolipids appear to be identical among three strains of P. falciparum and between two species, P. falciparum and P. knowlesi. In contrast, there are stage specific differences in glycolipid synthesis among rings, schizonts, gametocytes, and a mixture of gametes plus zygotes of P. falciparum, examples of both erythrocytic and vector forms of the parasite.
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Chulay JD, Schneider I, Cosgriff TM, Hoffman SL, Ballou WR, Quakyi IA, Carter R, Trosper JH, Hockmeyer WT. Malaria transmitted to humans by mosquitoes infected from cultured Plasmodium falciparum. Am J Trop Med Hyg 1986; 35:66-8. [PMID: 3511753 DOI: 10.4269/ajtmh.1986.35.66] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Malaria was transmitted to six normal human volunteers by mosquitoes infected from cultured gametocytes of Plasmodium falciparum. This method, which offers advantages over other methods of infecting volunteers, will be useful for evaluating the efficacy of human malaria vaccines.
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McCutchan TF, Welsh JA, Dame JB, Quakyi IA, Graves PM, Drake JC, Allegra CJ. Mechanism of pyrimethamine resistance in recent isolates of Plasmodium falciparum. Antimicrob Agents Chemother 1984; 26:656-9. [PMID: 6393866 PMCID: PMC179988 DOI: 10.1128/aac.26.5.656] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Clones of Plasmodium falciparum prepared from recent isolates of infected blood were studied to determine the molecular mechanism of naturally occurring pyrimethamine resistance. Total DNA, as well as thymidylate synthetase and dihydrofolate reductase activities, were characterized from these lines. Restriction analysis of DNA from pyrimethamine-susceptible and -resistant lines of the parasite showed no obvious amplification of any DNA fragment. Further, analysis of DNA from resistant and susceptible lines by centrifugation in cesium chloride-ethidium bromide revealed no extrachromosomal amplification in the resistant line. Comparison of the dihydrofolate reductase enzyme activity in the two lines revealed similar KmS for substrate but a large difference in the inhibition constant for pyrimethamine. Additionally, the enzyme from the resistant line was considerably more stable in vitro than the corresponding enzyme from the susceptible line. The thymidylate synthetase activity in the two lines was similar and unaffected by pyrimethamine. The mechanism of drug resistance in this isolate involves altered properties of the dihydrofolate reductase conferring both a different affinity for the drug and increased stability.
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Adu D, Williams DG, Quakyi IA, Voller A, Anim-Addo Y, Bruce-Tagoe AA, Johnson GD, Holborow EJ. Anti-ssDNA and antinuclear antibodies in human malaria. Clin Exp Immunol 1982; 49:310-6. [PMID: 6982135 PMCID: PMC1536512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
The incidence of serum antinuclear antibodies and serum antibodies to single stranded (ss) and double stranded (ds) DNA was investigated following acute malaria in 58 Caucasians visiting tropical countries but resident in Britain and in 24 Ghanaians resident in Ghana. In Caucasians this infection was associated with a significant increase in the incidence of speckled antinuclear antibodies (38% compared to 3% in controls; P less than 0.001) and a significant rise in antibody levels against ssDNA (14% compared to 5%; P less than 0.05), but no rise in antibodies against dsDNA. Acute malaria in Ghanaians was associated with an incidence of 25% of antinuclear antibodies and 4% of antibodies to ssDNA; these were similar to those found in healthy Ghanaians who are chronically exposed to malaria. Antibodies against dsDNA were not detected. The incidence of antinuclear antibodies and levels of anti-ssDNA antibodies was higher in the Ghanaian healthy population than in normal Caucasians. These observations indicate that malaria is associated with the development of antinuclear and anti-ssDNA antibodies. Ghanaian patients with a tropical splenomegaly syndrome or with a nephrotic syndrome, both of which conditions are suspected of having a malarial aetiology, had serum levels of anti-ssDNA higher than healthy controls. This observation adds further circumstantial evidence to the role of malaria in causing anti-DNA antibodies.
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Quakyi IA. The development and validation of an enzyme linked immunosorbent assay for malaria. Tropenmed Parasitol 1980; 31:325-33. [PMID: 7003852] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
ELISA has been evaluated and validated for malaria. It is sensitive, specific and reproducible. A comparison of ELISA and IFAT has been made, and there is a good correlation between the two tests. ELISA results can be assessed objectively. A small study on Caucasians with clinical malaria shows the value of ELISA as an immunodiagnostic tool. Its seroepidemiological value is also demonstrated, since it quickly reflects the changes in malaria transmission after a WHO malaria control programme in a malaria endemic area.
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Riches PG, Quakyi IA, Gibbs MR, Addison AE. Normal serum immunoglobulin and albumin levels in adult Ghanaians compared with levels in adults in Europe. Trop Geogr Med 1980; 32:151-7. [PMID: 7423604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Serum immunoglobulin and albumin levels have been determined in 50 male and 50 female Ghanaians from the greater Accra region. The subjects, as far as could be ascertained, were healthy, with no observed parasitaemia or fever within a fortnight of sampling. The results have been analysed and compared with European values obtained from blood-donors of laboratory workers in South East England. As a result of this study normal ranges at the 95% confidence limits are suggested for IgG, IgA, IgM and albumin for urban Ghanaians.
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