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Query: UMLS:C0024530 (malaria)
 44,886 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Burkitt's lymphoma is characterized by particular epidemiological features. It is a frequent childhood tumor in children in tropical Africa and occurs at a much lesser frequency all over the world. Chromosomal translocation affecting the long arm of chromosome 8 (band 8q24) and one of the chromosomes carrying the immunoglobulin loci (chromosomes 2, 14 or 22) are regularly observed in Burkitt's lymphoma, regardless of whether the tumor occurred in high or low incidence areas. The prevalence of Burkitt's lymphoma in Africa appears to be related to two factors: holo- or hyperendemic malaria and presence of Epstein-Barr virus genomes in the tumor cells. We present a model of pathogenesis, in which stimulation of B cells by malaria is the primary event in the development of the disease. The risk of the chromosomal translocation should be increased by increasing the number of new B cells generated per time. According to our model, the translocation leads to constitutive c-myc activation and makes the cells responsive to growth factors without inducing proliferation on its own. Infection of a translocation-carrying cell with EBV may provide an additional growth advantage and drive the cell further towards a fully malignant state.
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PMID:[Chromosome translocations and Epstein-Barr virus in Burkitt's lymphoma]. 282 99

A demographic and serological survey of Epstein-Barr virus infection was carried out in 5 geographically representative regions of Ethiopia. 80% of the 500 people studied were under 15 years of age. 82% of children under 5 years of age and 94% under 10 years of age were positive for IgG anti-viral capsid antigen (VCA) antibody. 51 of 100 children under 12 months of age and from 5 different provinces were positive for anti-VCA antibody. Of these, 23 were under 6 months. The distribution of anti-VCA antibody positivity was comparable in both sexes, in each age group and in the different provinces at different altitudes. Economic status, expressed in terms of estimated income, type of water supply, mode of excreta disposal and family size, did not significantly influence the distribution of anti-VCA antibody. Thus, early exposure to Epstein-Barr virus, with asymptomatic or subclinical presentation, probably accounts for the rarity of typical infectious mononucleosis in young adult Ethiopians. The lack of a relationship between Epstein-Barr virus infection and Burkitt's lymphoma, nasopharyngeal carcinoma, malaria as well as liver diseases is briefly discussed.
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PMID:Serological and demographic survey of Epstein-Barr virus infection in Ethiopia. 283 81

Plasmodium brasilianum causes chronic quartan malaria in the common marmoset Callithrix jacchus, whereas Epstein-Barr virus (EBV) infection is followed by an infectious mononucleosis-like syndrome that resolves. We infected weanling marmosets with one or both of these pathogens. Timing of the infections influenced outcome. Six animals were simultaneously infected with both agents; four became seriously ill (with accompanying proteinuria and edema) and either died or were killed. Histopathology indicated that glomerulonephritis had developed. The two survivors had more-prolonged parasitemia than did animals infected with P. brasilianum alone, as did animals infected with EBV before P. brasilianum. Five of the six simultaneously infected animals had absent or low titers of antibody to Epstein-Barr viral capsid antigens when compared with the other EBV-infected animals. Our results suggest that combined infection may be part of the etiology of quartan malarial nephropathy.
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PMID:Glomerulonephritis in common marmosets infected with Plasmodium brasilianum and Epstein-Barr virus. 284 17

The recognition of Burkitt lymphoma (BL) as a clinical syndrome and a pathological entity in African children resulted from astute clinical observations (bedside epidemiology), the availability of cancer registry data and accurate pathological interpretation. Following the early studies in Africa, it soon became evident that this tumor occurred worldwide and the excess of cases in Africa was an incidence phenomenon associated with specific environmental factors. The sentinel discovery of the Epstein Barr virus (EBV) and its association with BL stimulated a wide variety of scientific investigations which have had an impact of virtually every discipline and biology. Epidemiological observations linked to modern laboratory techniques have provided etiological insights which implicate specific environmental factors and genetic events in the pathogenesis of BL and other immunoproliferative diseases. Early infection with EBV and holoendemic malaria are clearly of paramount importance in the development of endemic BL (eBL). These factors do not play a role in the majority of sporadic BL (sBL) cases, but immunosuppression and T-cell deregulation almost certainly are common denominators. The final or principle genetic event in both instances would appear to be the chromosome 8 translocation involving the c-myc oncogene and structural alteration. It is expected that the BL model will continue to be a useful one for identifying basic mechanisms in carcinogenesis which may be applicable as well to a variety of non-neoplastic diseases.
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PMID:Malignant lymphoma in African children: three decades of discovery. 285 87

The Epstein-Barr virus (EBV), a B lymphotropic virus, is involved in a growing number of immunopathological disorders benign or malignant. The X-linked lymphoproliferative syndrome and its multifaceted clinical expression in a unique situation described in this issue by Purtilo. Among recent findings, the association between EBV and idiopathic interstitial pneumopathy (also named cryptogenic fibrosing alveolitis), is to be noted (6). From a molecular biology view-point, in vitro immortalization of B lymphocytes by EBV is under a pluri-genic (EBNA 2, EBNA 1, LYDMA) control. The role of EBV in oncogenesis appears different in Burkitt's Lymphoma (BL) and in nasopharyngeal carcinoma (NPC). In development of African BL, EBV appears to initiate the multistage carcinogenic event, through an early and massive infection. Other events include specific depression of T-cell immunity by hyperendemic malaria and c-myc onc-gene activation through chromosome translocation. In the genesis of NPC, the role of EBV still remain to be clarified although the strong and consistent association between EBV and the undifferentiated carcinoma of the nasopharyngeal (NPC) around the world favours an etiological relationship. The simple detection of IgA antibodies to VCA and EA allows early detection of the NPC, thus permitting a 95% cure rate at 5 years post-radiotherapy. Such an early diagnostic is of paramount public health importance. Furthermore, IgA/VCA and IgA/EA antibodies characterize precancerous conditions, giving the theoretical possibility of preventive interventions.
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PMID:The Epstein-Barr virus (EBV): a Rosetta Stone for understanding the role of viruses in immunopathological disorders and in human carcinogenesis. 299 May 89

Burkitt's lymphoma (BL) in tropical Africa represents by far the most common tumour in children between 0 and 14 years of age, 97% of the tumours being associated with Epstein-Barr virus (EBV). In North Africa, the tumour is about ten times less frequent than in equatorial Africa, but, according to reports from Algeria, 85% of the cases appear to be associated with EBV. In Western countries, BL represents about 3% of childhood tumours, 10 to 15% of them EBV-associated. Thus, from the northern industrialized countries to the equatorial developing countries, increasing incidences of lymphomas of the BL type are paralleled by an increasing proportion of EBV-associated cases. The Ugandan BL prospective study showed that high antibody titres to viral capsid antigen (VCA) preceded BL development by many years, with a quantifiable relationship between the level of VCA antibodies and tumour risk. If an early and/or massive EBV primary infection seems to represent the critical event for BL development in equatorial Africa, the favourable conditions for EBV-associated tumours in North Africa and in Europe remain to be investigated. Malaria appears to favour BL development through an EBV-specific T-cell immune deficiency. Chromosomal translocations and oncogene activation, considered as the final step in lymphoma development, do not appear to be related to EBV. Intervention against the virus may represent the ultimate proof of a causal relationship between EBV and the majority of BL cases around the world.
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PMID:Epstein-Barr virus and Burkitt's lymphoma worldwide: the causal relationship revisited. 299 87

Events surrounding infection and disease in infectious mononucleosis are a model for epidemiological factors that may affect the phase of initiation, the phase of promotion and the phase of tumour development in African Burkitt's lymphoma (BL). Consideration of the circumstances of early Epstein-Barr virus (EBV) infection as the initiator, and of malaria as the promoter, of African BL reveal some shortcomings in the evidence incriminating malaria. Possible factors leading to the emergence of the clinical tumour suggest that other factors may be involved. The absence of EBV and malarial infection in some cases of American BL indicate that they are neither necessary nor sufficient causes of the tumour in all settings.
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PMID:Epidemiology of Burkitt's lymphoma: other risk factors. 299 89

Supernatants from Epstein-Barr virus (EBV)--stimulated B lymphocytes obtained from two adult Gambians who were partially immune to malaria markedly inhibited the growth of Plasmodium falciparum in vitro (55-95% inhibition). When 22 separate colonies were derived by micromanipulation from one of these primary cultures and their supernatants assayed, the degree of inhibition correlated with levels of IgG fluorescent antibody and total IgG. The inhibitory anti-P. falciparum IgG immunoprecipitated an antigen of mol. wt 195,000, identified as the major schizont surface glycoprotein by dual biosynthetic labelling with 3H-glucosamine or 35S-methionine. Other studies on the analogous schizont surface protein of rodent malarias have shown that this antigen stimulates protective immunity. Production of this inhibitory antibody by adult Gambians may therefore contribute to their immunity to malaria. Human antibodies produced by EBV-stimulated B lymphocytes may be used to identify other important P. falciparum antigens and have potential applications for immunotherapy.
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PMID:Inhibition of Plasmodium falciparum growth by IgG antibody produced by human lymphocytes transformed with Epstein-Barr virus. 300 52

Stable human hybridomas were generated that produced inhibitory anti-Plasmodium falciparum monoclonal antibodies. Peripheral blood lymphocytes, obtained from adults in Liberia, a malaria endemic area, were immortalized with Epstein-Barr virus and then fused with KR4, a human, lymphoblastoid cell line. Stable hybridomas that produced anti-P. falciparum monoclonal antibody were identified by an ELISA assay that used the trophozoite and schizont antigens of both the Honduras I and FCR3 parasite strains. Monoclonal antibodies produced by selected hybridomas derived from lymphocytes of two individuals were subsequently studied. The anti-parasite antibodies were produced at 1-3 micrograms/ml in culture supernatants. All of the monoclonal antibodies bound specifically to trophozoites and schizonts of both strains of parasite in an indirect immunofluorescence assay and inhibited production of ring stage parasites by more than 90% when added to trophozoite or schizont containing erythrocytes in culture. Western immunoblot analysis of antigens obtained from trophozoites and schizonts (parasite age span of 36 to 48 h) was performed using either affinity purified or ammonium sulfate-concentrated monoclonal antibody. Antibody from three hybridomas which bound primarily to antigens of the Honduras 1 strain had Mr of approximately 140,000, 130,000 and 123,000.
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PMID:Plasmodium falciparum-inhibitory monoclonal antibodies produced by human hybridomas. 329 24

Pf 155, a protein of the human malaria parasite Plasmodium falciparum, is strongly immunogenic in humans and is believed to be a prime candidate for the preparation of a vaccine. Human monoclonal antibodies to Pf 155 were obtained by cloning B cells that had been prepared from an immune donor and transformed with Epstein-Barr virus. When examined by indirect immunofluorescence, these antibodies stained the surface of infected erythrocytes, free merozoites, segmented schizonts, and gametocytes. They bound to a major polypeptide with a relative molecular weight of 155K and to two minor ones (135K and 120K), all having high affinity for human glycophorin. The antibodies strongly inhibited merozoite reinvasion in vitro, suggesting that they might be appropriate reagents for therapeutic administration in vivo.
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PMID:Human monoclonal antibodies to Pf 155, a major antigen of malaria parasite Plasmodium falciparum. 351 Apr 52


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