1
|
Carter R, Wijesekera SK, Karunaweera ND, Mendis KN. Mediators and Mechanisms Associated with Paroxysm in Plasmodium vivax Malaria. J Pharm Pharmacol 2011. [DOI: 10.1111/j.2042-7158.1997.tb06158.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- R Carter
- Division of Biological Sciences, ICAPB, University of Edinburgh, Edinburgh EH9 3JT, UK
| | - S K Wijesekera
- University of Colombo, Faculty of Medicine, Malaria Research Unit, Colombo 8, Sri Lanka
| | - N D Karunaweera
- University of Colombo, Faculty of Medicine, Malaria Research Unit, Colombo 8, Sri Lanka
| | - K N Mendis
- University of Colombo, Faculty of Medicine, Malaria Research Unit, Colombo 8, Sri Lanka
| |
Collapse
|
2
|
Abstract
For over a century it has been recognized that many of the clinical symptoms of malaria are caused by toxins released by rupturing schizonts, but it is only in the past few years that the underlying mechanisms have begun to be understood. Dominic Kwiatkowski here focuses on the toxins that cause malaria fever by stimulating host cells to produce tumour necrosis factor a (TNF) and other pyrogenic cytokines. Both TNF and fever have antiparasite properties, and it is proposed that the release of these toxins plays an important role in the regulation of parasite density within the host. Cerebral malaria is related to excessive TNF production. Recent data indicate that this can be the consequence of genetic variation in the host's propensity to produce TNF.
Collapse
Affiliation(s)
- D Kwiatkowski
- Department of Paediatrics, John Radcliffe Hospital, Oxford, UK.
| |
Collapse
|
3
|
Abstract
The paroxysms of Plasmodium vivax malaria are antiparasite responses that, although distressing to the human host, almost never impart serious acute pathology. Using plasma and blood cells from P. vivax patients, the cellular and noncellular mediators of these events have been studied ex vivo. The host response during a P. vivax paroxysm was found to involve T cells, monocytes and neutrophils, and the activity, among others, of the pyrogenic cytokines tumor necrosis factor alpha and interleukin 2 in addition to granulocyte macrophage-colony stimulating factor. However, interferon gamma activity, associated with serious acute pathogenesis in other studies on malaria, was absent. Induction of the cytokines active during a P. vivax paroxysm depends upon the presence of parasite products, which are released into the plasma before the paroxysm. Chemical identification of these natural parasite products will be important for our understanding of pathogenesis and protection in malaria.
Collapse
|
4
|
Boutlis CS, Gowda DC, Naik RS, Maguire GP, Mgone CS, Bockarie MJ, Lagog M, Ibam E, Lorry K, Anstey NM. Antibodies to Plasmodium falciparum glycosylphosphatidylinositols: inverse association with tolerance of parasitemia in Papua New Guinean children and adults. Infect Immun 2002; 70:5052-7. [PMID: 12183552 PMCID: PMC128285 DOI: 10.1128/iai.70.9.5052-5057.2002] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Individuals living in regions of intense malaria transmission exhibit natural immunity that facilitates persistence of parasitemia at controlled densities for much of the time without symptoms. This aspect of immunity has been referred to as malarial "tolerance" and is thought to partly involve inhibition of the chain of events initiated by a parasite toxin(s) that may otherwise result in cytokine release and symptoms such as fever. Antibodies to the candidate Plasmodium falciparum glycosylphosphatidylinositol (GPI) toxin have been viewed as likely mediators of such tolerance. In this study, the relationship between antibodies to P. falciparum GPIs, age, and parasitemia was determined in asymptomatic children and adults living in Madang, Papua New Guinea. The prevalence and intensity of antibody responses increased with age and were lowest in children 1 to 4 years old with the highest-density parasitemias. In children of this age group who were tolerant of parasitemia during the study, only 8.3% had detectable immunoglobulin G (IgG) and none had IgM antibodies to GPI. This suggests that anti-GPI antibodies are unlikely to be the sole mediator of malarial tolerance, especially in children younger than 5 years. Following antimalarial treatment, clearance of parasitemia led to a fall in anti-GPI IgG response in children and adolescents within 6 weeks. As anti-GPI antibodies potentially play a role in protecting against disease progression, our results caution against the treatment of asymptomatic parasitemia and suggest that generation of a sustained antibody response in children poses a challenge to novel antitoxic vaccination strategies.
Collapse
Affiliation(s)
- Craig S Boutlis
- Department of Tropical Medicine and International Health, Menzies School of Health Research, Casuarina, Australia
| | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Gowda DC, Davidson EA. Protein glycosylation in the malaria parasite. PARASITOLOGY TODAY (PERSONAL ED.) 1999; 15:147-52. [PMID: 10322336 DOI: 10.1016/s0169-4758(99)01412-x] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The nature and extent of glycosylation in Plasmodium falciparum has long been controversial. It has been widely believed that O-glycosylation is the major carbohydrate modification in the intraerythrocytic stage of P. falciparum and that the parasite has no N-glycosylation capacity. Contrary to this, recent studies have demonstrated that P. falciparum has a low N-glycosylation capability, and O-glycosylation is either absent or present at an extremely low level, whereas glycosylphosphatidylinositol (GPI) anchor modification is common and is the major carbohydrate modification in parasite proteins. The GPI anchor moieties are essential for parasite survival. The parasite GPI anchors can activate signaling pathways in host cells, and thereby induce the expression of inflammatory cytokines, adhesion molecules and induced nitric oxide synthase (iNOS). This might cause erythrocyte sequestration, hypoglycemia, triglyceride lipogenesis and immune dysregulation. Thus, the parasite GPI anchor structure and biosynthetic pathways are attractive targets for antimalarial and/or antiparasite drug development, as discussed here by Channe Gowda and Eugene Davidson.
Collapse
Affiliation(s)
- D C Gowda
- Department of Biochemistry and Molecular Biology, Georgetown University Medical Center, Washington, DC 20007, USA.
| | | |
Collapse
|
6
|
McKenzie FE, Bossert WH. Multispecies Plasmodium infections of humans. J Parasitol 1999; 85:12-8. [PMID: 10207356 PMCID: PMC2481388] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023] Open
Abstract
We analyzed point-prevalence data from 19 recent studies of human populations in which either Plasmodium ovale or Plasmodium vivax co-occur with Plasmodium falciparum and Plasmodium malariae. Although the only statistical interactions among, sympatric congeners are pairwise, the frequencies of mixed-species infections relative to standard hypotheses of species sampling independence show no strong relation to overall malaria prevalence. The striking difference between the P. falciparum-P. malariae-P. ovale and the P. falciparum-P. malariae-P. vivax data is that the first typically shows a statistical surplus of mixed-species infections and the second a deficit. This suggests that the number of Plasmodium species present in a human population may be less important in determining the frequencies of mixed-species infections than is the identity of those species.
Collapse
Affiliation(s)
- F E McKenzie
- Department of Organismic and Evolutionary Biology, Harvard University, Cambridge Massachusetts 02138, USA
| | | |
Collapse
|
7
|
Maitland K, Williams TN, Peto TE, Day KP, Clegg JB, Weatherall DJ, Bowden DK. Absence of malaria-specific mortality in children in an area of hyperendemic malaria. Trans R Soc Trop Med Hyg 1997; 91:562-6. [PMID: 9463668 DOI: 10.1016/s0035-9203(97)90026-2] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We conducted a prospective community-based malaria surveillance study on a cohort of children < 10 years old living in an area of hyperendemic malaria (spleen rates > 50% in children aged 2-9 years) in Vanuatu, Melanesia, supported by a concurrent prospective descriptive study of malaria admissions to the local hospital. The incidence of clinical malaria in children < 10 years old was 1.9 episodes/year. The annual incidence of severe malaria (severe malarial anaemia and cerebral malaria) was only 2/1000 in children aged < 5 years. The only manifestation of severe malaria seen in indigenous children was anaemia. No death could be attributed to malaria. While the incidence of uncomplicated clinical malaria in this population was comparable to that in many parts of Africa, the incidence of severe forms of the disease was significantly lower. This could not be attributed to differing rates of malaria transmission, chloroquine resistance, or to host protective or behavioural factors. These findings suggest that studies which compare disease patterns in geographically disparate populations may be instrumental in developing a better understanding of the determinants of clinical outcome in Plasmodium falciparum malaria and that such regional differences must be considered when planning or interpreting the effects of malaria interventions.
Collapse
Affiliation(s)
- K Maitland
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
| | | | | | | | | | | | | |
Collapse
|
8
|
Maitland K, Williams TN, Newbold CI. Plasmodium vevax and P. falciparum: Biological interactions and the possibility of cross-species immunity. ACTA ACUST UNITED AC 1997; 13:227-31. [PMID: 15275075 DOI: 10.1016/s0169-4758(97)01061-2] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The question of whether infection of humans with one species of malaria parasite alters the course of infection with another has been largely ignored because no such interaction was found during studies of induced malaria in patients with neurosyphilis. However, in animal model systems some degree of cross-species interaction is the rule rather than the exception. Furthermore, recent epidemiological observations in Vanuatu in the South Pacific have suggested a biological interaction between the dominant species, Plasmodium vivax, and P. falciparum. Kathryn Maitland, Tom Williams and Chris Newbold here speculate on the basis of these observations and other published findings that infection with P. vivax may result in the development of immunity sufficient to ameliorate the clinical course of subsequent infections with the potentially lethal parasite P. falciparum.
Collapse
Affiliation(s)
- K Maitland
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK.
| | | | | |
Collapse
|
9
|
Williams TN, Maitland K, Bennett S, Ganczakowski M, Peto TE, Newbold CI, Bowden DK, Weatherall DJ, Clegg JB. High incidence of malaria in alpha-thalassaemic children. Nature 1996; 383:522-5. [PMID: 8849722 DOI: 10.1038/383522a0] [Citation(s) in RCA: 203] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The alpha+-thalassaemias are the commonest known human genetic disorders, affecting up to 80 per cent of some populations. Although there is good evidence from both epidemiological and clinical studies that these gene frequencies reflect selection by, and protection from, malaria, the mechanism is unknown. We have studied the epidemiology of malaria in childhood on the southwestern Pacific island of Espiritu Santo in Vanuatu and here we report that, paradoxically, both the incidence of uncomplicated malaria and the prevalence of splenomegaly, an index of malaria infection, are significantly higher in young children with alpha+-thalassaemia than in normal children. Furthermore, this effect is most marked in the youngest children and for the non-lethal parasite Plasmodium vivax. The alpha+-thalassaemias may have been selected for their ability beneficially to increase susceptibility to P. vivax, which, by acting as a natural vaccine in this community, induces limited cross-species protection against subsequent severe P. falciparum malaria.
Collapse
Affiliation(s)
- T N Williams
- Institute of Molecular Medicine, John Radcliffe Hospital, Headington, Oxford, UK
| | | | | | | | | | | | | | | | | |
Collapse
|
10
|
Sheikh NA, Caro HN, Taverne J, Playfair JH, Rademacher TW. Malaria: a tumour necrosis factor inhibitor from parasitized erythrocytes. Immunology 1996; 87:461-6. [PMID: 8778034 PMCID: PMC1384117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The excessive production of tumour necrosis factor (TNF) is associated with the pathology of blood-stage malaria and phosphatidylinositol-containing phospholipid antigens from parasitized erythrocytes stimulate its secretion by macrophages, thus acting as toxins. This brief report describes some properties of an inhibitor present in lysates from erythrocytes infected with malarial parasites that blocked the detection of recombinant TNF in an enzyme-linked immunosorbent assay and diminished or abolished the cytotoxicity of TNF. It was not found in control lysates of normal erythrocytes. Its addition to macrophage cultures stimulated by toxic malarial preparations or by bacterial lipopolysaccharide also blocked the detection of TNF. These findings may explain the contradictory results obtained from different assays for TNF, and emphasize the need for caution when interpreting the results of a single assay system. If released when parasitized erythrocytes rupture in vivo, the inhibitor could help protect both parasite and host from the damaging effects of TNF.
Collapse
Affiliation(s)
- N A Sheikh
- Department of Immunology, University College London Medical School, UK
| | | | | | | | | |
Collapse
|
11
|
Willimann K, Matile H, Weiss NA, Imhof BA. In vivo sequestration of Plasmodium falciparum-infected human erythrocytes: a severe combined immunodeficiency mouse model for cerebral malaria. J Exp Med 1995; 182:643-53. [PMID: 7650476 PMCID: PMC2192159 DOI: 10.1084/jem.182.3.643] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Cerebral malaria is a fatal complication of infection by Plasmodium falciparum in man. The neurological symptoms that characterize this form of malarial disease are accompanied by the adhesion of infected erythrocytes to the vasculature of the brain. To study this phenomenon in vivo, an acute phase severe combined immunodeficiency (SCID) mouse model was developed in which sequestration of P. falciparum-infected human erythrocytes took place. During acute cerebral malaria in humans, the expression of intercellular adhesion molecule-1 (ICAM-1) is induced in vascular endothelium by inflammatory reactions. Acute phase ICAM-1 expression can also be obtained in SCID mice. The endothelium of the midbrain region was the most responsive to such inflammatory stimulus. It is noteworthy that the reticular formation in the midbrain controls the level of consciousness, and loss of consciousness is a symptom of cerebral malaria. We found that infected human erythrocytes were retained 24 times more than normal erythrocytes in ICAM-1-positive mouse brain. Sequestration to the brain was reduced by anti-ICAM-1 antibodies. These in vivo results were confirmed by the binding of P. falciparum-infected erythrocytes to the ICAM-1-positive endothelium in tissue sections of mouse brain. We conclude that the SCID mouse serves as a versatile in vivo model that allows the study of P. falciparum-infected erythrocyte adhesion as it occurs in human cerebral malaria. Upregulation of ICAM-1 expression in the region of the midbrain correlates with increased retention of malaria-infected erythrocytes and with the symptoms of cerebral malaria.
Collapse
MESH Headings
- Animals
- Base Sequence
- Cell Adhesion
- Endothelium, Vascular/physiopathology
- Erythrocytes/parasitology
- Female
- Host-Parasite Interactions
- Intercellular Adhesion Molecule-1/genetics
- Intercellular Adhesion Molecule-1/physiology
- L Cells
- Lung/parasitology
- Malaria, Cerebral/blood
- Malaria, Cerebral/complications
- Malaria, Cerebral/parasitology
- Malaria, Falciparum/blood
- Malaria, Falciparum/complications
- Malaria, Falciparum/parasitology
- Mesencephalon/parasitology
- Mice
- Mice, Inbred BALB C
- Mice, SCID/blood
- Mice, SCID/parasitology
- Molecular Sequence Data
- Plasmodium falciparum/physiology
- Recombinant Proteins/metabolism
- Severe Combined Immunodeficiency/complications
- Specific Pathogen-Free Organisms
- Transfection
Collapse
Affiliation(s)
- K Willimann
- Department of Medical Parasitology, Swiss Tropical Institute, Basel
| | | | | | | |
Collapse
|
12
|
Abstract
In this review the old concept of severe malaria as a toxic disease is re-examined in the light of recent discoveries in the field of cytokines. Animal studies suggest that the induction of TNF by parasite-derived molecules may be partly responsible for cerebral malaria and anemia, while hypoglycaemia may be due to direct effects of similar molecules on glucose metabolism. These molecules appear to be phospholipids and we suggest that when fully characterized they might form the basis of antitoxic therapy for malaria.
Collapse
Affiliation(s)
- P H Jakobsen
- Department of Infectious Disease M7722, University Hospital, Copenhagen, Denmark
| | | | | | | |
Collapse
|
13
|
Jakobsen PH, Morris-Jones S, Rønn A, Hviid L, Theander TG, Elhassan IM, Bygbjerg IC, Greenwood BM. Increased plasma concentrations of sICAM-1, sVCAM-1 and sELAM-1 in patients with Plasmodium falciparum or P. vivax malaria and association with disease severity. Immunology 1994; 83:665-9. [PMID: 7533138 PMCID: PMC1415057] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Increased serum concentrations of soluble intercellular adhesion molecule-1 (sICAM-1), soluble endothelial leucocyte adhesion molecule-1 (sELAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were detected in Danish malaria patients infected with sequestering Plasmodium falciparum or non-sequestering P. vivax parasites, as well as in patients with sepsis or meningitis. Levels of soluble adhesion molecules remained elevated in the P. falciparum patients for several weeks after initiation of treatment. Plasma concentrations of sICAM-1, sVCAM-1 and sELAM-1 were higher in Gambian children with severe P. falciparum malaria than in children with mild malaria. Plasma levels of sVCAM-1 and sELAM-1 were significantly correlated. Plasma levels of sELAM-1 and sVCAM-1 may reflect endothelial inflammatory reactions and these reactions may be harmful for humans infected with malaria parasites.
Collapse
Affiliation(s)
- P H Jakobsen
- Department of Infectious Diseases, University Hospital (Rigshospitalet), Copenhagen, Denmark
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Bate CA, Kwiatkowski D. Inhibitory immunoglobulin M antibodies to tumor necrosis factor-inducing toxins in patients with malaria. Infect Immun 1994; 62:3086-91. [PMID: 8039876 PMCID: PMC302931 DOI: 10.1128/iai.62.8.3086-3091.1994] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cytokines such as tumor necrosis factor alpha (TNF) appear to play an important role in the pathogenesis of malaria. We have previously shown that TNF is produced in response to substances released at schizont rupture, which we have called malaria toxins. In mice these toxins stimulate a T cell-independent antibody response, generating short-lived immunoglobulin M (IgM) antibodies that inhibit the TNF-inducing activity of the toxins. We report here that a similar antibody response is seen in humans. Serum from a European adult infected with Plasmodium falciparum inhibited the induction of TNF by malaria toxins derived from P. falciparum-infected erythrocytes. We found that IgM antibodies were responsible for the inhibitory activity. These inhibitory antibodies could not be detected in convalescent-phase serum collected from the same patient 6 weeks later or in sera from healthy European and African controls. The antibodies appeared to be malaria specific in that they inhibited TNF induction by a variety of P. falciparum isolates but failed to inhibit TNF induction by bacterial lipopolysaccharide or lipoteichoic acid. The inhibitory antibodies bound to liposomes containing phosphatidylinositol but not other phospholipids. Serum from a European adult infected with P. vivax also inhibited the activity of toxins derived from P. falciparum-infected erythrocytes, and this too was mediated by IgM antibodies which were malaria specific and bound to phosphatidylinositol liposomes.
Collapse
Affiliation(s)
- C A Bate
- Department of Paediatrics, John Radcliffe Hospital, Oxford, United Kingdom
| | | |
Collapse
|
15
|
Bate C, Kwiatkowski DP, Taverne J, Playfair JH. Immunizing against toxic malarial antigens: Reply. ACTA ACUST UNITED AC 1994; 10:24. [PMID: 15275560 DOI: 10.1016/0169-4758(94)90351-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
16
|
Affiliation(s)
- A A Holder
- Division of Parasitology, National Institute for Medical Research, London, UK
| |
Collapse
|
17
|
Hommel M. Amplification of cytoadherence in cerebral malaria: towards a more rational explanation of disease pathophysiology. ANNALS OF TROPICAL MEDICINE AND PARASITOLOGY 1993; 87:627-35. [PMID: 8122926 DOI: 10.1080/00034983.1993.11812821] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cerebral malaria in man and in mice is the consequence of a cascade of events, involving the production of toxins by the parasite and cytokines by the host, and eventually leading to the amplification of the expression of the receptors for cytoadherence on brain capillary endothelial cells. Variations in the intrinsic characteristics of parasite isolates or the genetic make-up of the host and the degree of antimalarial immunity can modulate this sequence of events. A working hypothesis is proposed in which two features of the parasite, the ability to cytoadhere and to produce toxins, are clearly dissociated and where the amplification of cytoadherence receptors is considered crucial. This hypothesis, illustrated by new data from human malaria and rodent models, suggests that cerebral malaria may occur when these features occur together during an infection, while not necessarily within the same parasite clone.
Collapse
Affiliation(s)
- M Hommel
- School of Tropical Medicine, Liverpool, U.K
| |
Collapse
|
18
|
Abstract
Those developmental stages of malaria parasites that infect erythrocytes are responsible for the severe morbidity and mortality associated with this disease. The nature and specificity of the slowly acquired immunity seen in endemic populations remain to be defined, but significant progress has been made recently in identifying specific blood-stage proteins, characterizing immune responses to them, and exploring the dynamics of non-specific host responses to infection.
Collapse
Affiliation(s)
- C A Long
- Department of Microbiology and Immunology, Hahnemann University, Philadelphia, Pennsylvania 19102-1192
| |
Collapse
|
19
|
Prada J, Prager C, Neifer S, Bienzle U, Kremsner PG. Production of interleukin-6 by human and murine mononuclear leukocytes stimulated with Plasmodium antigens is enhanced by pentoxifylline, and tumor necrosis factor secretion is reduced. Infect Immun 1993; 61:2737-40. [PMID: 8500916 PMCID: PMC280911 DOI: 10.1128/iai.61.6.2737-2740.1993] [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: 01/31/2023] Open
Abstract
When pentoxifylline was present during stimulation of human mononuclear leukocytes with Plasmodium falciparum exogenous antigens, an increase in interleukin-6 production was observed simultaneously with a reduction of tumor necrosis factor secretion. Similar results were obtained in murine macrophages stimulated with P. vinckei antigens. This indicates the independence of interleukin-6 and tumor necrosis factor secretion in response to malaria antigens.
Collapse
Affiliation(s)
- J Prada
- Landesinstitut für Tropenmedizin Berlin, Germany
| | | | | | | | | |
Collapse
|
20
|
Bate CA, Taverne J, Kwiatkowski D, Playfair JH. Phospholipids coupled to a carrier induce IgG antibody that blocks tumour necrosis factor induction by toxic malaria antigens. Immunology 1993; 79:138-45. [PMID: 8509134 PMCID: PMC1422040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Phospholipid-containing antigens of malaria parasites stimulate macrophages to secrete tumour necrosis factor (TNF), induce hypoglycaemia and are toxic to mice. This TNF induction is inhibited by antisera made against the antigens, the inhibitory activity of which can be removed specifically by adsorption to phosphatidylinositol (PI) liposomes. Although the same was true of antisera made against PI, the inhibitory activity of antisera made against some other phospholipids appeared to be directed against a common determinant, probably the phosphate ester head group. We have shown previously that the activity of all the antisera was associated mainly with IgM and was not boosted by repeated injections of the antigens. To try and induce a secondary response against the parasite antigens using non-toxic molecules, mice were immunized with various phosphorylated compounds coupled to keyhole limpet haemocyanin (KLH). Three injections of PI-KLH or of phosphatidylserine (PS) coupled to KLH induced significantly higher titres of inhibitory antibody than one; furthermore, the inhibitory activity was mainly in the IgG fraction. The antisera did not inhibit TNF induction by lipopolysaccharide (LPS) or lipoteichoic acid. However, antisera against PS-KLH, though not PI-KLH, inhibited the induction of TNF by the phospholipid, platelet-activating factor (PAF). These antisera, and antisera from mice immunized with phospho-threonine or galactosamine-1-phosphate conjugated to KLH, contained inhibitory antibodies of differing specificities. Mice immunized with PI-KLH, PS-KLH or phospho-threonine-KLH did not develop hypoglycaemia when challenged with the parasite toxic antigens. These results indicate that the antigenicity of non-toxic analogues can be dramatically enhanced by coupling to a protein carrier.
Collapse
Affiliation(s)
- C A Bate
- Department of Paediatrics, John Radcliffe Hospital, Headington, Oxford, U.K
| | | | | | | |
Collapse
|
21
|
Kremsner PG, Nüssler A, Neifer S, Chaves MF, Bienzle U, Senaldi G, Grau GE. Malaria antigen and cytokine-induced production of reactive nitrogen intermediates by murine macrophages: no relevance to the development of experimental cerebral malaria. Immunology 1993; 78:286-90. [PMID: 8473017 PMCID: PMC1421792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The in vitro production of reactive nitrogen intermediates (RNI) by murine macrophages was evaluated in response to heat-stable malaria antigen and cytokines. Malaria antigen, interferon-gamma (IFN-gamma) and tumour necrosis factor (TNF) induced RNI production in macrophages in a dose-dependent way. RNI production steadily increased over a 2-day period and was enhanced when the malaria antigen was co-incubated with IFN-gamma and/or TNF. RNI production induced by either IFN-gamma or malaria antigen or a combination of the two was suppressed by pentoxifylline in a dose-dependent manner. Pentoxifylline did not significantly influence TNF-induced RNI production. L-N-monomethyl arginine reduced malaria antigen, IFN-gamma and TNF-induced RNI production when these reagents were used in combination or alone. An anti-TNF monoclonal antibody (mAb) reduced IFN-gamma-induced RNI production, but did not significantly alter the malaria antigen-induced RNI synthesis by macrophages. The influence of inhibitors of nitric oxide synthase, L-N-monomethyl arginine and N omega-nitro-L-arginine, was studied in experimental cerebral malaria. They did not exert any significant effect on the development of cerebral malaria in Plasmodium berghei ANKA-infected CBA/J mice.
Collapse
Affiliation(s)
- P G Kremsner
- Landesinstitut für Tropenmedizin Berlin, Germany
| | | | | | | | | | | | | |
Collapse
|
22
|
Abstract
For the hundreds of millions of people presently infected with malaria, survival may depend on relatively non-specific immune effector mechanisms. Progress has been made in understanding the anti-parasitic properties of tumor necrosis factor-alpha, interferon-gamma and nitric oxide, in defining the parasite toxins that induce tumor necrosis factor-alpha production, and in exploring the role of cytokines and adhesion molecules in the pathogenesis of cerebral malaria.
Collapse
Affiliation(s)
- D Kwiatkowski
- Institute of Molecular Medicine, John Radcliffe Hospital, Oxford, UK
| |
Collapse
|
23
|
Bate CA, Taverne J, Playfair JH. Detoxified exoantigens and phosphatidylinositol derivatives inhibit tumor necrosis factor induction by malarial exoantigens. Infect Immun 1992; 60:1894-901. [PMID: 1563780 PMCID: PMC257091 DOI: 10.1128/iai.60.5.1894-1901.1992] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
We have previously shown that malaria parasites liberate exoantigens which, through a phospholipid component, stimulate mouse macrophages to secrete tumor necrosis factor (TNF), which are toxic to D-galactosamine-sensitized mice, and which therefore might be involved in pathology. Plasmodium yoelii exoantigens detoxified by dephosphorylation or digestion with lipases do not induce TNF production. However, these partial structures inhibited its production in response to the exoantigens, although not to bacterial lipopolysaccharide (LPS). When pure phospholipids were tested in a macrophage assay, none stimulated the production of TNF, but phosphatidylinositol (PI) inhibited TNF induction by P. yoelii exoantigens. Moreover, inositol monophosphate (IMP) was the only one of a number of monophosphate saccharides tested which was inhibitory; inositol was not. Macrophages pretreated with PI, IMP, or detoxified exoantigens and then incubated with parasite exoantigens also yielded much less TNF. PI, IMP, and lipase-digested exoantigens of P. yoelii similarly inhibited the TNF-inducing activity of exoantigens of the human parasites Plasmodium falciparum and Plasmodium vivax. Neither PI nor IMP diminished TNF production in response to LPS, in contrast to a platelet-activating factor antagonist [1-O-hexadecyl-2-acetyl- sn-glycero-3-phospho(N,N,N-trimethyl hexanolamine)] which inhibited both exoantigen- and LPS-induced production of TNF. We conclude that at least two different parts of the molecule are involved in the induction of TNF secretion by parasite exoantigens: one requires the presence of a phosphate bound to inositol, and, since dephosphorylated exoantigens were also inhibitory, one does not. It would seem that both affect interactions between parasite-derived exoantigens and the macrophage receptors.
Collapse
Affiliation(s)
- C A Bate
- Department of Immunology, University College & Middlesex School of Medicine, London, United Kingdom
| | | | | |
Collapse
|