1
|
Carter LM, Pollitt LC, Wilson LG, Reece SE. Ecological influences on the behaviour and fertility of malaria parasites. Malar J 2016; 15:220. [PMID: 27091194 PMCID: PMC4835847 DOI: 10.1186/s12936-016-1271-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 04/01/2016] [Indexed: 12/26/2022] Open
Abstract
Background Sexual reproduction in the mosquito is essential for the transmission of malaria parasites and a major target for transmission-blocking interventions. Male gametes need to locate and fertilize females in the challenging environment of the mosquito blood meal, but remarkably little is known about the ecology and behaviour of male gametes. Methods Here, a series of experiments explores how some aspects of the chemical and physical environment experienced during mating impacts upon the production, motility, and fertility of male gametes. Results and conclusions Specifically, the data confirm that: (a) rates of male gametogenesis vary when induced by the family of compounds (tryptophan metabolites) thought to trigger gamete differentiation in nature; and (b) complex relationships between gametogenesis and mating success exist across parasite species. In addition, the data reveal that (c) microparticles of the same size as red blood cells negatively affect mating success; and (d) instead of swimming in random directions, male gametes may be attracted by female gametes. Understanding the mating ecology of malaria parasites, may offer novel approaches for blocking transmission and explain adaptation to different species of mosquito vectors. Electronic supplementary material The online version of this article (doi:10.1186/s12936-016-1271-0) contains supplementary material, which is available to authorized users.
Collapse
|
2
|
Aka P, Emmanuel B, Vila MC, Jariwala A, Nkrumah F, Periago MV, Neequaye J, Kiruthu C, Levine PH, Biggar RJ, Bhatia K, Bethony JM, Mbulaiteye SM. Elevated serum levels of interleukin-6 in endemic Burkitt lymphoma in Ghana. Hematol Oncol 2014; 32:218-20. [PMID: 24493366 DOI: 10.1002/hon.2121] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2013] [Revised: 11/06/2013] [Accepted: 11/08/2013] [Indexed: 11/05/2022]
Affiliation(s)
- Peter Aka
- Division of Cancer Epidemiology and Genetics, DCEG, NCI, Bethesda, Maryland, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
3
|
McQueen PG, Williamson KC, McKenzie FE. Host immune constraints on malaria transmission: insights from population biology of within-host parasites. Malar J 2013; 12:206. [PMID: 23767770 PMCID: PMC3691866 DOI: 10.1186/1475-2875-12-206] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Accepted: 05/30/2013] [Indexed: 02/07/2023] Open
Abstract
Background Plasmodium infections trigger complex immune reactions from their hosts against several life stages of the parasite, including gametocytes. These immune responses are highly variable, depending on age, genetics, and exposure history of the host as well as species and strain of parasite. Although the effects of host antibodies that act against gamete stages in the mosquito (due to uptake in the blood meal) are well documented, the effects of host immunity upon within-host gametocytes are not as well understood. This report consists of a theoretical population biology-based analysis to determine constraints that host immunity impose upon gametocyte population growth. The details of the mathematical models used for the analysis were guided by published reports of clinical and animal studies, incorporated plausible modalities of immune reactions to parasites, and were tailored to the life cycl es of the two most widespread human malaria pathogens, Plasmodium falciparum and Plasmodium vivax. Results For the same ability to bind and clear a target, the model simulations suggest that an antibody attacking immature gametocytes would tend to lower the overall density of transmissible mature gametocytes more than an antibody attacking the mature forms directly. Transmission of P. falciparum would be especially vulnerable to complete blocking by antibodies to its immature forms since its gametocytes take much longer to reach maturity than those of P. vivax. On the other hand, antibodies attacking the mature gametocytes directly would reduce the time the mature forms can linger in the host. Simulation results also suggest that varying the standard deviation in the time necessary for individual asexual parasites to develop and produce schizonts can affect the efficiency of production of transmissible gametocytes. Conclusions If mature gametocyte density determines the probability of transmission, both Plasmodium species, but especially P. falciparum, could bolster this probability through evasion or suppression of host immune responses against the immature gametocytes. However, if the long term lingering of mature gametocytes at low density in the host is also important to ensure transmission, then evasion or suppression of antibodies against the mature stages would bolster probability of transmission as well.
Collapse
Affiliation(s)
- Philip G McQueen
- Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland, USA.
| | | | | |
Collapse
|
4
|
Abeles SR, Chuquiyauri R, Tong C, Vinetz JM. Human host-derived cytokines associated with Plasmodium vivax transmission from acute malaria patients to Anopheles darlingi mosquitoes in the Peruvian Amazon. Am J Trop Med Hyg 2013; 88:1130-7. [PMID: 23478585 DOI: 10.4269/ajtmh.12-0752] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
Infection of mosquitoes by humans is not always successful in the setting of patent gametocytemia. This study tested the hypothesis that pro- or anti-inflammatory cytokines are associated with transmission of Plasmodium vivax to Anopheles darlingi mosquitoes in experimental infection. Blood from adults with acute, non-severe P. vivax malaria was fed to laboratory-reared F1 An. darlingi mosquitoes. A panel of cytokines at the time of mosquito infection was assessed in patient sera and levels compared among subjects who did and did not infect mosquitoes. Overall, blood from 43 of 99 (43%) subjects led to mosquito infection as shown by oocyst counts. Levels of IL-10, IL-6, TNF-α, and IFN-γ were significantly elevated in vivax infection and normalized 3 weeks later. The anti-inflammatory cytokine IL-10 was significantly higher in nontransmitters compared with top transmitters but was not in TNF-α and IFN-γ. The IL-10 elevation during acute malaria was associated with P. vivax transmission blocking.
Collapse
|
5
|
Kastenmüller K, Espinosa DA, Trager L, Stoyanov C, Salazar AM, Pokalwar S, Singh S, Dutta S, Ockenhouse CF, Zavala F, Seder RA. Full-length Plasmodium falciparum circumsporozoite protein administered with long-chain poly(I·C) or the Toll-like receptor 4 agonist glucopyranosyl lipid adjuvant-stable emulsion elicits potent antibody and CD4+ T cell immunity and protection in mice. Infect Immun 2013; 81:789-800. [PMID: 23275094 PMCID: PMC3584875 DOI: 10.1128/iai.01108-12] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2012] [Accepted: 11/29/2012] [Indexed: 01/28/2023] Open
Abstract
The Plasmodium falciparum circumsporozoite (CS) protein (CSP) is a major vaccine target for preventing malaria infection. Thus, developing strong and durable antibody and T cell responses against CSP with novel immunogens and potent adjuvants may improve upon the success of current approaches. Here, we compare four distinct full-length P. falciparum CS proteins expressed in Escherichia coli or Pichia pastoris for their ability to induce immunity and protection in mice when administered with long-chain poly(I · C) [poly(I · C)LC] as an adjuvant. CS proteins expressed in E. coli induced high-titer antibody responses against the NANP repeat region and potent CSP-specific CD4(+) T cell responses. Moreover, E. coli-derived CS proteins in combination with poly(I · C)LC induced potent multifunctional (interleukin 2-positive [IL-2(+)], tumor necrosis factor alpha-positive [TNF-α(+)], gamma interferon-positive [IFN-γ(+)]) CD4(+) effector T cell responses in blood, in spleen, and particularly in liver. Using transgenic Plasmodium berghei expressing the repeat region of P. falciparum CSP [Pb-CS(Pf)], we showed that there was a 1- to 4-log decrease in malaria rRNA in the liver following a high-dose challenge and ~50% sterilizing protection with a low-dose challenge compared to control levels. Protection was directly correlated with high-level antibody titers but not CD4(+) T cell responses. Finally, protective immunity was also induced using the Toll-like receptor 4 agonist glucopyranosyl lipid adjuvant-stable emulsion (GLA-SE) as the adjuvant, which also correlated with high antibody titers yet CD4(+) T cell immunity that was significantly less potent than that with poly(I · C)LC. Overall, these data suggest that full-length CS proteins and poly(I · C)LC or GLA-SE offer a simple vaccine formulation to be used alone or in combination with other vaccines for preventing malaria infection.
Collapse
Affiliation(s)
- Kathrin Kastenmüller
- Vaccine Research Center and Cellular Immunology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| | - Diego A. Espinosa
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Lauren Trager
- Vaccine Research Center and Cellular Immunology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
- Virginia-Maryland Regional College of Veterinary Medicine, Blacksburg, Virginia, USA
| | - Cristina Stoyanov
- Vaccine Research Center and Cellular Immunology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland, USA
| | | | | | | | - Sheetij Dutta
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Christian F. Ockenhouse
- Division of Malaria Vaccine Development, Walter Reed Army Institute of Research, Silver Spring, Maryland, USA
| | - Fidel Zavala
- Department of Molecular Microbiology and Immunology, Bloomberg School of Public Health, The Johns Hopkins University, Baltimore, Maryland, USA
| | - Robert A. Seder
- Vaccine Research Center and Cellular Immunology Section, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland, USA
| |
Collapse
|
6
|
Mideo N, Reece SE, Smith AL, Metcalf CJE. The Cinderella syndrome: why do malaria-infected cells burst at midnight? Trends Parasitol 2013; 29:10-6. [PMID: 23253515 PMCID: PMC3925801 DOI: 10.1016/j.pt.2012.10.006] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Revised: 10/31/2012] [Accepted: 10/31/2012] [Indexed: 11/20/2022]
Abstract
An interesting quirk of many malaria infections is that all parasites within a host – millions of them – progress through their cell cycle synchronously. This surprising coordination has long been recognized, yet there is little understanding of what controls it or why it has evolved. Interestingly, the conventional explanation for coordinated development in other parasite species does not seem to apply here. We argue that for malaria parasites, a critical question has yet to be answered: is the coordination due to parasites bursting at the same time or at a particular time? We explicitly delineate these fundamentally different scenarios, possible underlying mechanistic explanations and evolutionary drivers, and discuss the existing corroborating data and key evidence needed to solve this evolutionary mystery.
Collapse
|
7
|
Karunaweera N, Wanasekara D, Chandrasekharan V, Mendis K, Carter R. Plasmodium vivax: paroxysm-associated lipids mediate leukocyte aggregation. Malar J 2007; 6:62. [PMID: 17517147 PMCID: PMC1891311 DOI: 10.1186/1475-2875-6-62] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2007] [Accepted: 05/22/2007] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Paroxysms are recurrent febrile episodes, characteristic of Plasmodium vivax infections, which coincide with the rupture of schizont-infected erythrocytes in the patients' circulation. The present study describes the formation of prominent aggregates of leukocytes in vitro in the presence of parasite and host factors released during paroxysms. METHODS Whole blood cells from uninfected malaria-naïve donors were incubated with plasma taken during a paroxysm or normal human plasma as a control and cell smears were observed under the microscope for the presence of leukocyte aggregates. Plasma factors involved in mediating the leukocyte aggregation were identified using immune depletion and reconstitution experiments. Furthermore, biochemical characterization was carried out to determine the chemical nature of the active moieties in plasma present during paroxysms. RESULTS Leukocyte aggregates were seen exclusively when cells were incubated in plasma collected during a paroxysm. Immune depletion and reconstitution experiments revealed that the host cytokines TNF-alpha, GM-CSF, IL-6 and IL-10 and two lipid fractions of paroxysm plasma comprise the necessary and sufficient mediators of this phenomenon. The two lipid components of the paroxysm plasmas speculated to be of putative parasite origin, were a phospholipid-containing fraction and another containing cholesterol and triglycerides. The phospholipid fraction was dependent upon the presence of cytokines for its activity unlike the cholesterol/triglyceride-containing fraction which in the absence of added cytokines was much more active than the phospholipids fraction. The biological activity of the paroxysm plasmas from non-immune patients who presented with acute P. vivax infections was neutralized by immune sera raised against schizont extracts of either P. vivax or Plasmodium falciparum. However, immune sera against P. vivax were more effective than that against P. falciparum indicating that the parasite activity involved may be antigenically at least partially parasite species-specific. CONCLUSION Leukocyte aggregation was identified as associated with paroxysms in P. vivax infections. This phenomenon is mediated by plasma factors including host-derived cytokines and lipids of putative parasite origin. The characteristics of the phospholipid fraction in paroxysm plasma are congruent with those of the parasite-derived, TNF-inducing GPI moieties described by others. The more active cholesterol/triglyceride(s), however, represent a novel malarial toxin, which is a new class of biologically active lipid associated with the paroxysm of P. vivax malaria.
Collapse
Affiliation(s)
- Nadira Karunaweera
- Malaria Research Unit, Department of Parasitology, Faculty of Medicine, University of Colombo,, P.O. Box 271, Kynsey Road, Colombo 08, Sri Lanka
| | - Deepani Wanasekara
- Malaria Research Unit, Department of Parasitology, Faculty of Medicine, University of Colombo,, P.O. Box 271, Kynsey Road, Colombo 08, Sri Lanka
| | | | - Kamini Mendis
- Malaria Research Unit, Department of Parasitology, Faculty of Medicine, University of Colombo,, P.O. Box 271, Kynsey Road, Colombo 08, Sri Lanka
| | - Richard Carter
- Institute of Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
8
|
Abstract
Mosquitoes of the genus Anopheles transmit malaria parasites to humans. Anopheles mosquito species vary in their vector potential because of environmental conditions and factors affecting their abundance, blood-feeding behavior, survival, and ability to support malaria parasite development. In the complex life cycle of the parasite in female mosquitoes, a process termed sporogony, mosquitoes acquire gametocyte-stage parasites from blood-feeding on an infected host. The parasites carry out fertilization in the midgut, transform to ookinetes, then oocysts, which produce sporozoites. Sporozoites invade the salivary glands and are transmitted when the mosquito feeds on another host. Most individual mosquitoes that ingest gametocytes do not support development to the sporozoite stage. Bottle-necks occur at every stage of the cycle in the mosquito. Powerful new techniques and approaches exist for evaluating malaria parasite development and for identifying mechanisms regulating malaria parasite-vector interactions. This review focuses on those interactions that are important for the development of new approaches for evaluating and blocking transmission in nature.
Collapse
Affiliation(s)
- J C Beier
- Department of Tropical Medicine, School of Public Health and Tropical Medicine, Tulane University, New Orleans, Louisiana 70112, USA.
| |
Collapse
|
9
|
Perlmann P, Perlmann H, Flyg BW, Hagstedt M, Elghazali G, Worku S, Fernandez V, Rutta AS, Troye-Blomberg M. Immunoglobulin E, a pathogenic factor in Plasmodium falciparum malaria. Infect Immun 1997; 65:116-21. [PMID: 8975900 PMCID: PMC174564 DOI: 10.1128/iai.65.1.116-121.1997] [Citation(s) in RCA: 69] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Most children and adults living in areas where the endemicity of Plasmodium falciparum malaria is high have significantly elevated levels of both total immunoglobulin E (IgE) and IgE antimalarial antibodies in blood. This elevation is highest in patients with cerebral malaria, suggesting a pathogenic role for this immunoglobulin isotype. In this study, we show that IgE elevation may also be seen in severe malaria without cerebral involvement and parallels an elevation of tumor necrosis factor alpha (TNF). IgE-containing serum from malaria immune donors was added to tissue culture plates coated with rabbit anti-human IgE antibodies or with P. falciparum antigen. IgE-anti-IgE complexes as well as antigen-binding IgE antibodies induced TNF release from peripheral blood mononuclear cells (PBMC). Nonmalaria control sera with no IgE elevation induced significantly less of this cytokine, and the TNF-inducing capacity of malaria sera was also strongly reduced by passing them over anti-IgE Sepharose columns. The cells giving rise to TNF were adherent PBMC. The release of this cytokine probably reflects cross-linking of their low-affinity receptors for IgE (CD23) by IgE-containing immune complexes known to give rise to monocyte activation via the NO transduction pathway. In line with this, adherent monocytic cells exposed to IgE complexes displayed increased expression of CD23. As the malaria sera contained IgG anti-IgE antibodies, such complexes probably also play a role in the induction of TNF in vivo. Overproduction of TNF is considered a major pathogenic mechanism responsible for fever and tissue lesions in P. falciparum malaria. This overproduction is generally assumed to reflect a direct stimulation of effector cells by certain parasite-derived toxins. Our results suggest that IgE elevation constitutes yet another important mechanism involved in excessive TNF induction in this disease.
Collapse
Affiliation(s)
- P Perlmann
- Department of Immunology, Stockholm University, Sweden.
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
The gametocytes of Plasmodium vinckei petteri, their morphological stages, periodicity and infectivity. Int J Parasitol 1996. [DOI: 10.1016/s0020-7519(96)80008-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
11
|
Abstract
The purpose of this review is to summarize the biology of Plasmodium in the mosquito including recent data to contribute to better understanding of the developmental interaction between mosquito and malarial parasite. The entire sporogonic cycle is discussed taking into consideration different parasite/vector interactions and factors affecting parasite development to the mosquito.
Collapse
Affiliation(s)
- A B Simonetti
- Departamento de Microbiologia, Universidade Federal do Rio Grande do Sul, Porto Alegre, Brasil.
| |
Collapse
|
12
|
Palmer GH, McElwain TF. Molecular basis for vaccine development against anaplasmosis and babesiosis. Vet Parasitol 1995; 57:233-53. [PMID: 7597787 DOI: 10.1016/0304-4017(94)03123-e] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Immunization of livestock against the erythroparasitic pathogens Anaplasma marginale, Babesia bigemina, and Babesia bovis with safe and effective killed vaccines is not yet feasible on a practical basis. However, the immune protection afforded by recovery from natural infection and premunition indicates that microbial epitopes capable of inducing immunity exist and that the bovine immune system can be primed appropriately. Induction of protection by immunization with killed parasite fractions, enriched for polypeptides with surface exposed epitopes, supports a focus on surface epitopes, including apical complex organellar epitopes in Babesia, for vaccine development. Cloning, sequencing, and expression of genes encoding these key surface polypeptides has allowed examination of polypeptide function and detailed analysis of epitope conservation in light of genetic polymorphism. In this paper, the characterization of these polypeptides at the epitope level and their roles in inducing protective immunity are reviewed. Definition of these epitopes, in combination with improved understanding of immune mechanisms, provides the basis for development of effective recombinant vaccines against anaplasmosis and babesiosis.
Collapse
Affiliation(s)
- G H Palmer
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman 99164, USA
| | | |
Collapse
|
13
|
Abstract
Immunity to malaria involves both cell-mediated and humoral immune mechanisms. T cells are essential both in regulating antibody formation and in inducing antibody-independent immunity. Thus, acquisition and maintenance of protective immunity to malaria is T-cell dependent. Although relatively neglected until recently basic knowledge of T-cell subsets and cytokine production determining the course of a malaria infection is advancing rapidly at present. In this paper we will review recent findings contributing to the understanding of immune mechanisms against the asexual blood stages of human P. falciparum malaria.
Collapse
|
14
|
Gyan B, Troye-Blomberg M, Perlmann P, Björkman A. Human monocytes cultured with and without interferon-gamma inhibit Plasmodium falciparum parasite growth in vitro via secretion of reactive nitrogen intermediates. Parasite Immunol 1994; 16:371-5. [PMID: 7970876 DOI: 10.1111/j.1365-3024.1994.tb00362.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Adherent cells from human peripheral blood were studied for their interaction with asexual blood forms of Plasmodium falciparum in vitro. Freshly isolated monocytes only showed weak anti-parasitic effects. However, an enhancement of this anti-parasitic activity was apparent when monocytes were allowed to mature in vitro. Monocytes activated with IFN-gamma for two or three days had an enhanced anti-parasitic effect. In contrast, the inhibition mediated by cells incubated for five days was the same with or without IFN-gamma treatment. There was no evidence of toxicity when IFN-gamma at high concentrations was added directly to P. falciparum cultures. The anti-parasitic activity of the activated cells seemed to be due to nitric oxide since incubation of macrophages with L-NMMA reduced the level of inhibition. However, inhibition was only partial suggesting that other factors also were involved in inhibition of parasite growth.
Collapse
Affiliation(s)
- B Gyan
- Department of Immunology, Stockholm University, Sweden
| | | | | | | |
Collapse
|
15
|
Landau I, Chabaud A. Plasmodium species infecting Thamnomys rutilans: a zoological study. ADVANCES IN PARASITOLOGY 1994; 33:49-90. [PMID: 8122568 DOI: 10.1016/s0065-308x(08)60411-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- I Landau
- Biologie Parasitaire, Muséum National d'Histoire Naturelle, Paris, France
| | | |
Collapse
|
16
|
|
17
|
Hellriegel B. Modelling the immune response to malaria with ecological concepts: short-term behaviour against long-term equilibrium. Proc Biol Sci 1993; 250:249-56. [PMID: 1362993 DOI: 10.1098/rspb.1992.0156] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
A model for the human immune response to the malaria parasite Plasmodium falciparum is used to analyse the dynamics of an infection within an individual patient. Previous models either looked at competition between two parasite genotypes or at one parasite clone and the immune response to it. This model describes the course of an infection caused by the blood stages of two parasite genotypes differing in reproductive rate and in the immune response they elicit. The interactions between the genotypes can be interpreted as exploitative competition for red blood cells. Interactions between omnipotent immune cells and parasites resemble a predator-prey relation. In analysing these kinds of models, classical theoretical ecology usually deals with long-term behaviours, i.e. looks for equilibria and conditions for coexistence. However, especially in endemic regions with ongoing transmission, an equilibrium state of infections is unlikely. When reinfections with another parasite genotype were considered, the short-term dynamics of the infection changed dramatically, depending on which genotype was first, when the second one appeared, and what kind of immune response was elicited. If the slow development of immunity to malaria really is due to its genotype specificity, the effects of superinfections will be of great importance.
Collapse
|
18
|
Motard A, Landau I, Nussler A, Grau G, Baccam D, Mazier D, Targett GA. The role of reactive nitrogen intermediates in modulation of gametocyte infectivity of rodent malaria parasites. Parasite Immunol 1993; 15:21-6. [PMID: 8433851 DOI: 10.1111/j.1365-3024.1993.tb00568.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Direct feeding of Anopheles stephensi mosquitoes on mice infected with Plasmodium vinckei petteri showed that, during the periods of schizogony in the blood, the infectivity of gametocytes was markedly reduced. This could be prevented by prior injection of the L-arginine analogue, Nw-nitro-L-arginine (NwNLA) showing that the altered infectivity was due to reactive nitrogen intermediates (RNI). Similar effects on transmission of P. yoelii nigeriensis were demonstrated in vitro by membrane feeding of the mosquitoes. The in vitro reduction in infectivity could be reversed by injecting the L-arginine analogue either into the infected mouse donor of serum, or into the membrane feeding chamber. Elevated levels of TNF and IL-6 were demonstrated during the course of infection but did not correlate well with nitrogen radical activity. Similarly, direct measurements of NO2- and NO3- did not reflect the nitrogen radical activity revealed by addition of the specific L-arginine analogue.
Collapse
Affiliation(s)
- A Motard
- Muséum National d'Histoire Naturelle, Paris, France
| | | | | | | | | | | | | |
Collapse
|
19
|
Singh PP, Dutta GP. Comparative evaluation of the colony-stimulating factors induction potential of Plasmodium cynomolgi-infected monkey erythrocytes and soluble antigens. Acta Trop 1992; 51:247-55. [PMID: 1359752 DOI: 10.1016/0001-706x(92)90043-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Plasmodium cynomolgi total antigens soluble in culture medium (P.c.SA), and noninfective P. cynomolgi-infected monkey erythrocytes (P.c.IE) were compared for their potential to induce colony-stimulating factors (CSFs). When injected intravenously in monkeys, both preparations induced an increase in the serum CSFs levels; P.c.IE appeared to be 1.6-fold more potent than the P.c.SA. In vitro P.c.IE induced 1.8-fold more CSF by monkey blood monocyte-derived macrophages than P.c. However, both in vivo and in vitro, the peak CSFs levels induced by P.c.SA were attained apparently 8 h earlier. CSF generated by P.c.SA and P.c.IE induced the formation of macrophage, granulocyte and granulocyte-macrophage colonies, in vitro; P.c.IE-generated CSF induced the formation of significantly (P < 0.01) higher numbers of granulocyte-macrophage colonies, indicating that the CSF induced by them stimulated different biological responses. The CSF induction appeared to be LPS-independent.
Collapse
Affiliation(s)
- P P Singh
- Division of Microbiology, Central Drug Research Institute, Lucknow, India
| | | |
Collapse
|
20
|
Karunaweera ND, Carter R, Grau GE, Kwiatkowski D, Del Giudice G, Mendis KN. Tumour necrosis factor-dependent parasite-killing effects during paroxysms in non-immune Plasmodium vivax malaria patients. Clin Exp Immunol 1992; 88:499-505. [PMID: 1351432 PMCID: PMC1554505 DOI: 10.1111/j.1365-2249.1992.tb06478.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Plasmodium vivax malaria infections in non-immune individuals manifest as periodic clinical episodes of fever with chills and rigors known as paroxysms. We have demonstrated that in non-immune patients the period of paroxysm is associated with the transient presence of plasma factors which kill gametocytes, the intra-erythrocytic sexual stages of the malaria parasite which transmit the infection from humans to mosquito, rendering them non-infectious to mosquitoes. Gametocyte killing in paroxysm plasma is mediated by tumour necrosis factor (TNF) acting in conjunction with other essential serum factor(s). Plasma TNF levels were elevated during a paroxysm. In semi-immune individuals from a P. vivax-endemic area clinical symptoms of malaria are mild and the parasite killing factors are not induced during paroxysm. Serum TNF levels were correspondingly lower in endemic patients during a paroxysm. Human peripheral blood mononuclear cells (PBMC) can be stimulated in vitro by extracts of P. vivax blood stage parasites to produce TNF and associated parasite killing factor(s), thus simulating in vitro the events that occur during a paroxysm, this being the release of parasite exo-antigens by rupturing schizonts and the subsequent induction of PBMC to produce TNF and other parasite-killing factors. We were able to show that convalescent serum from P. vivax semi-immune individuals block the induction of TNF and parasite-killing factors by malaria antigens in vitro, presumably through antibodies that neutralize parasite exo-antigens. Thus, individuals living in malaria-endemic areas appear to acquire clinical immunity to malaria by avoiding their induction during infection; we have shown that one such mechanism is the neutralization of parasite exo-antigens that induce the production of parasite killing factors.
Collapse
Affiliation(s)
- N D Karunaweera
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | | | | | | | | |
Collapse
|
21
|
Kumaratilake LM, Robinson BS, Ferrante A, Poulos A. Antimalarial properties of n-3 and n-6 polyunsaturated fatty acids: in vitro effects on Plasmodium falciparum and in vivo effects on P. berghei. J Clin Invest 1992; 89:961-7. [PMID: 1541684 PMCID: PMC442944 DOI: 10.1172/jci115678] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The polyunsaturated fatty acids docosahexaenoic acid (C22:6,n-3), eicosapentaenoic acid, arachidonic acid, and linoleic acid caused marked in vitro growth inhibition of Plasmodium falciparum, assessed by a radiometric assay. In contrast, negligible parasite killing was seen with oleic acid or docosanoic acid. Parasite killing was significantly increased when oxidized forms of polyunsaturated fatty acids were used. Antioxidants greatly reduced the fatty acid-induced killing. Mice infected with P. berghei and treated for 4 d with C22:6,n-3 showed marked reduction in parasitemia. The anemia associated with the infection was also alleviated by treatment with C22:6,n-3. The data provide new information that could be explored in order to develop new strategies in malaria treatment.
Collapse
Affiliation(s)
- L M Kumaratilake
- Department of Immunology, Adelaide Children's Hospital, Australia
| | | | | | | |
Collapse
|
22
|
Bate CA, Taverne J, Karunaweera ND, Mendis KN, Kwiatkowski D, Playfair JH. Serological relationship of tumor necrosis factor-inducing exoantigens of Plasmodium falciparum and Plasmodium vivax. Infect Immun 1992; 60:1241-3. [PMID: 1541540 PMCID: PMC257621 DOI: 10.1128/iai.60.3.1241-1243.1992] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Exoantigens of Plasmodium vivax-parasitized erythrocytes stimulated macrophages to secrete tumor necrosis factor, and antisera raised against the exoantigens inhibited this secretion. The antisera also inhibited the activity of Plasmodium falciparum and Plasmodium yoelii exoantigens, and conversely, antisera against the latter cross-reacted with the exoantigens of P. vivax.
Collapse
Affiliation(s)
- C A Bate
- Department of Immunology, University College and Middlesex School of Medicine, London, United Kingdom
| | | | | | | | | | | |
Collapse
|
23
|
Affiliation(s)
- R S Phillips
- Department of Zoology, University of Glasgow, U.K
| |
Collapse
|
24
|
Mendis C, Del Giudice G, Gamage-Mendis AC, Tougne C, Pessi A, Weerasinghe S, Carter R, Mendis KN. Anti-circumsporozoite protein antibodies measure age related exposure to malaria in Kataragama, Sri Lanka. Parasite Immunol 1992; 14:75-86. [PMID: 1557232 DOI: 10.1111/j.1365-3024.1992.tb00007.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Antibodies to two peptides DDAAD and (NANP)40 representing the repetitive sequence of circumsporozoite antigens (CS protein) of P. vivax and P. falciparum respectively were measured in a cohort of 149 and 107 individuals respectively at four, 6 monthly blood surveys performed on residents of Kataragama, a P. vivax malaria endemic region in southern Sri Lanka. The prevalence of antibodies to the CS protein of both species was relatively low being less than 20% to either peptide in the population as a whole, this being consistent with the low entomological inoculation rates in the area. A marked age related prevalence pattern was evident, with the prevalence of antibodies increasing with age to reach between 25 to 30% in the 25-50 year age group in both P. vivax and P. falciparum. The population had had a life long exposure to P. vivax malaria but not to P. falciparum, an epidemic of which occurred in this region a few months prior to the beginning of this study. Nevertheless, the age-related prevalence of these antibodies was identical with respect to the two species. This suggests that the age-related prevalence pattern reflected differences in inoculation rates between the age groups due to differences in exposure to inoculation rather than an age acquired response resulting from a cumulative experience over several years. An analysis of antibody prevalence in individuals showed first, that sporozoite inoculations must have been clustered rather than homogeneously distributed in the population and secondly, that sero-conversion did not correlate with malaria infections in these individuals.
Collapse
Affiliation(s)
- C Mendis
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Brown AE, Teja-Isavadharm P, Webster HK. Macrophage activation in vivax malaria: fever is associated with increased levels of neopterin and interferon-gamma. Parasite Immunol 1991; 13:673-9. [PMID: 1811217 DOI: 10.1111/j.1365-3024.1991.tb00562.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In order to evaluate the relationship between fever and macrophage activation in vivax malaria, serum interferon-gamma (IFN-gamma) and urinary neopterin concentrations were determined in Thai adults with Plasmodium vivax parasitaemia. Magnitude of fever, after controlling for parasite density, was found to be positively correlated with both IFN-gamma (r = 0.47) and neopterin (r = 0.57). In the 26 febrile patients, neopterin excretion increased further during the first two days of chemotherapy (P = 0.0002). Mean neopterin values for both groups had fallen to within the normal range by the sixth day post-treatment. Thus, the fever of vivax malaria was associated with IFN-gamma induced macrophage activation, as reflected by neopterin excretion.
Collapse
Affiliation(s)
- A E Brown
- Department of Immunology and Biochemistry, Armed Forces Research Institute for Medical Sciences, Bangkok, Thailand
| | | | | |
Collapse
|
26
|
Affiliation(s)
- V A Snewin
- Unité d'Immunoparasitologie, CNRS URA 361, Institut Pasteur, Paris
| | | | | |
Collapse
|
27
|
Behr C, Dubois P. Evaluation of human T-cell response to malaria antigens in naturally acquired immunity. RESEARCH IN IMMUNOLOGY 1991; 142:643-9. [PMID: 1817291 DOI: 10.1016/0923-2494(91)90142-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- C Behr
- Unité de Parasitologie expérimentale, Institut Pasteur, Paris
| | | |
Collapse
|
28
|
Affiliation(s)
- D Kwiatkowski
- Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK
| |
Collapse
|
29
|
Kwiatkowski D, Nowak M. Periodic and chaotic host-parasite interactions in human malaria. Proc Natl Acad Sci U S A 1991; 88:5111-3. [PMID: 2052590 PMCID: PMC51821 DOI: 10.1073/pnas.88.12.5111] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
It has been recognized since ancient times that malaria fever is highly periodic but the mechanism has been poorly understood. Malaria fever is related to the parasite growth cycle in erythrocytes. After a fixed period of replication, a mature parasite (schizont) causes the infected erythrocyte to rupture, releasing progeny that quickly invade other erythrocytes. Simultaneous rupture of a large number of schizonts stimulates a host fever response. Febrile temperatures are damaging to Plasmodium falciparum, particularly in the second half of its 48-hr replicative cycle. Using a mathematical model, we show that these interactions naturally tend to generate periodic fever. The model predicts chaotic parasite population dynamics at high multiplication rates, consistent with the classical observation that P. falciparum causes less regular fever than other species of parasite.
Collapse
Affiliation(s)
- D Kwiatkowski
- Institute of Molecular Medicine, Oxford University, John Radcliffe Hospital, United Kingdom
| | | |
Collapse
|
30
|
|
31
|
Mendis KN, David PH, Carter R. Antigenic polymorphism in malaria: is it an important mechanism for immune evasion? IMMUNOLOGY TODAY 1991; 12:A34-7. [PMID: 2069676 DOI: 10.1016/s0167-5699(05)80010-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Malarial infections do not readily evoke an effective protective immunity against re-infection. Possible reasons for this include the ability of the parasites to interfere with the host's immune response and to evade the response in an immune host, by, for example, exploiting antigenic polymorphism or variation. Antigenic polymorphism undoubtedly exists in malaria parasite populations but does this polymorphism actually contribute to immune evasion by the parasite? Here, Kamini Mendis and colleagues examine the evidence for this and its implications for future malaria vaccines.
Collapse
Affiliation(s)
- K N Mendis
- Dept of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | | |
Collapse
|
32
|
Mazier D, Mattei D. Parasite heat-shock proteins and host responses: the balance between protection and immunopathology. SPRINGER SEMINARS IN IMMUNOPATHOLOGY 1991; 13:37-53. [PMID: 1723224 DOI: 10.1007/bf01225277] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- D Mazier
- INSERM U 313, Groupe Hospitalier Pitié-Salpetrière, Paris, France
| | | |
Collapse
|
33
|
Naotunne TS, Karunaweera ND, Del Giudice G, Kularatne MU, Grau GE, Carter R, Mendis KN. Cytokines kill malaria parasites during infection crisis: extracellular complementary factors are essential. J Exp Med 1991; 173:523-9. [PMID: 1900073 PMCID: PMC2118826 DOI: 10.1084/jem.173.3.523] [Citation(s) in RCA: 103] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Malaria infection crisis, at which the parasitemia drops precipitously and the parasite loses infectivity to the mosquito vector, occurs in many natural malaria systems, and has not been explained. We demonstrate that in a simian malaria parasite (Plasmodium cynomolgi in its natural host, the toque monkey), the loss of infectivity during crisis is due to the death of circulating intraerythrocytic gametocytes mediated by crisis serum. These parasite-killing effects in crisis serum are due to the presence in the serum of cytokines tumor necrosis factor and interferon gamma, which are produced by the host as a result of the malaria infection. The killing activity of each cytokine is absolutely dependent upon the presence of additional, as yet unidentified factor(s) in the crisis serum.
Collapse
Affiliation(s)
- T S Naotunne
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | | | | | | | | | | |
Collapse
|
34
|
Mendis KN, Naotunne TD, Karunaweera ND, Del Giudice G, Grau GE, Carter R. Anti-parasite effects of cytokines in malaria. Immunol Lett 1990; 25:217-20. [PMID: 2126526 DOI: 10.1016/0165-2478(90)90118-a] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cytokines induced during natural malaria infections, e.g., at crisis of a blood infection of Plasmodium cynomolgi, and during clinical paroxysms in human Plasmodium vivax infections, mediate killing of intra-erythrocytic blood stage malaria parasites. These cytokines, TNF and IFN-gamma, require additional, yet unidentified complementary factors that are present in "crisis" and "paroxysm" serum to kill intra-erythrocytic blood stage parasites. In contrast, cytokines, (mainly IFN-gamma) are able to effect killing of intra-hepatic stages of the parasite by themselves independent of serum complementary factors, suggesting that the mechanisms of killing may be different with respect to the two parasite stages. Cytokines also appear to be critical intermediates in mechanisms of clinical disease in malaria. Serum cytokine (TNF) levels and killing effects on blood stage malaria parasites were lower in patients who were exposed to endemic P. vivax malaria who had partial clinical immunity, than in non-immune patients. Evidence suggest that individuals acquire natural immunity to the disease by avoiding the induction of high levels of cytokines and complementary factors.
Collapse
Affiliation(s)
- K N Mendis
- Department of Parasitology, Faculty of Medicine, University of Colombo, Sri Lanka
| | | | | | | | | | | |
Collapse
|