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

Antibody formation, endotoxin sensitivity, and resistance to a challenge malarial infection were evaluated in mice fed a diet containing polychlorinated biphenyl (PCB) (Aroclor 1242) or hexachlorobenzene (HCB). Antibody synthesis to the antigen sheep RBC (SRBC) was significantly depressed in the PCB- and HCB-treated (167 ppm) animals as evidenced by the fact that control mice elicited an approximate twofold increase in antibody formation over the chemical-treated mice. Serum IgA concentrations in the PCB- and HCB-treated mice were consistently 40--80 mg/dl lower than control values. Gram-negative endotoxin (Salmonella typhosa) sensitivity in PCB- and HCB-treated mice was increased 5.2- and 32-fold, respectively, following the dietary administration of 167 ppm of Aroclor 1242 or HCB for 6 weeks. An endotoxin hypersusceptibility was also noted at 3 weeks after dietary administration. Decreased resistance to a malaria challenge was also demonstrated in the xenobiotic-treated mice. A 20% decrease in mean survival time of mice fed Aroclor 1242 for 3 to 6 weeks and inoculated with Plasmodium berghei (NYU-2) was observed. Infected mice which had received HCB for 3 or 6 weeks manifested reductions in mean survival time of 24 and 31%, respectively. The data indicated that environmental chemical contaminants impair host resistance and, since no concomitant histopathological alterations were observed in the treated mice, the evaluation of immune parameters may possibly be a sensitive indicator of toxicity.
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PMID:Environmental chemical-induced immune dysfunction. 10 6

Gambian children with past or present Plasmodium falciparum malaria were investigated for the incidence of Coombs positivity using monospecific antisera. Approximately 50% were positive and the most frequent form of erythrocyte sensitization was with C3d. Other specificities, EIgG, EIgGC3d and EIgGC4bC3d were less common. Erthyrocytes were never found sensitized with IgA or IgM. There was no correlation between a positive test and age, tribal status or level of parasitaemia at presentation, although a positive test was often found in association with anaemia. Sensitized erythrocytes were present in the circulation for a period of up to 6 weeks following initial observation. The mechanism of erythrocyte sensitization is not known, but the results suggest a Type III complex-mediated hypersensitivity involving parasite antigen-antibody complexes. It is likely that these reactions contribute to the pathogenesis of the anaemia in falciparum malaria.
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PMID:Direct Coombs antiglobulin reactions in Gambian children with Plasmodium falciparum malaria. I. Incidence and class specificity. 37 80

Data are presented to support a relationship between malaria infection and Burkitt's lymphoma in African children. IgG, IgM and IgA levels were measured in sera from Burkitt's lymphoma patients and from sex- and age-matched, nearest-neighbour controls. All three classes of immunoglobulins were present in significantly lower amounts in the sera from Burkitt's lymphoma patients than in the sera from controls. The mechanism of this apparent B-cell suppression is not yet clear. Malaria-specific IgG and IgM antibody titres were determined in the indirect immunofluorescence test. No significant difference in the IgG malaria-specific antibodies was detected between the two groups of sera. Malaria antibody levels measured using IgM specific conjugates were significantly lower in the sera from Burkitt's lymphoma patients in reactions with Plasmodium falciparum antigen. No significant difference was observed when P. malariae was used. Confirmation of this finding would serve as a positive link between Burkitt's lymphoma and P. falciparum infection.
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PMID:Serum immunoglobulin levels and malaria antibodies in Burkitt's lymphoma. 37 87

Mice were infected with 1X 107 Plasmodium berghei Yoelii parasites intraperitoneally. Circulating parasite, malaria antibody and C3 concentrations were measures: parasitaemia and hypocomplementaemia were transient, but the antibody response was persistent. Animals were sacrificed at intervals and their kidneys examined: a glomerulonephritis associates with predominantly mesangial deposits of C3, IgG1, IgM and some IgA always developed after 7 days and persisted for up to 6 mth. Malaria antigen and antibody were demonstrated within the glomeruli. Microscopic haematuria occurred with proteinuria but without marked deterioration in renal function. Strains producing high and low affinity antibody were equally susceptible to the disease. Treatment with glucocorticoid, immunosuppressive, platelet function inhibiting and/or anticoagulant drugs, or indomethacin from the 1st day of infection failed to prevent development of the disease or to lead to its early cure. Eradication of the infection within its first 3 days prevented glomerular deposition of antibody and complement, and infection with a smaller antigen load followed by later treatment also produced subsequent cure.
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PMID:Mouse malaria nephropathy. 79 19

Schistosomiasis, the second major parasitic disease in the world after malaria affects at least 200 million people, 500 million being exposed to the risk of infection. It is widely agreed that a vaccine strategy which could lead to the induction of effector mechanisms reducing the level of reinfection and ideally parasite fecundity would deeply affect the incidence of pathological manifestations as well as the parasite transmission potentialities. Extensive studies performed in the rat model have allowed the identification of novel effector mechanisms involving IgE antibodies and various inflammatory cell populations (eosinophils, macrophages and platelets) whereas regulation of immune response by blocking antibodies has been evidenced. Recent epidemiological studies have now entirely confirmed in human populations the role of IgE antibodies in the acquisition of resistance and the association of IgG4 blocking antibodies with increased susceptibility. On the basis of these concepts, several schistosome target proteins have been identified and their encoding genes cloned. One of them, a schistosome glutathione S-transferase (Sm 28 GST) appears as a promising vaccine candidate. Immunization experiments have shown that two complementary goals can be achieved: (a) a partial but significant reduction of the worm population (up to 60% in rats); (b) a significant reduction of parasite fecundity (up to 70% in mice and 85% in cattle) and egg viability (up to 80%). At least two distinct immunological mechanisms account for these two effects. IgE antibodies appear as a major humoral component of acquired resistance whereas IgA antibodies appear as a major humoral factor affecting parasite fecundity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Vaccine strategies against schistosomiasis. 134 2

Humoral immune response of normal rhesus monkeys was studied after giving a standard dose of primaquine. The drug did not effect the level of complement (C3) and its haemolytic activity. Levels of Immunoglobulin i.e. IgG, IgM & IgA and number of immunoglobulin secreting cells also remained unaffected. Results of this study suggested that primaquine did not suppress the immune status of the host and could be given safely to the malaria patients.
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PMID:Humoral immune response of normal rhesus monkeys during primaquine administration. 184 4

Anti-malarial antibodies were quantified in cerebrospinal fluid (CSF) of 17 cases of cerebral malaria, 16 presumptive cases (no demonstrable parasitaemia in peripheral blood but responding to i.v. quinine therapy) of cerebral malaria, and 15 controls. A schizont-enriched Plasmodium knowlesi antigen was used in an ELISA. Anti-malarial antibodies of IgA and IgM isotypes were not detectable in most of the CSF samples analysed, although serum antibody titres were high. However, 88% of CSF from cerebral malaria and 56% of presumptive cerebral malaria cases had significant levels of IgG anti-malarial antibodies in comparison to control CSF. The antibody levels did not correlate with the severity of coma but correlated well with the duration of coma. The CSF malarial antibody titres were independent of degree of parasitaemia. The possible role of CSF anti-malarial antibodies in cerebral malaria in the light of recent demonstrations of intrathecal synthesis of immunoglobulins and deposition of immune complex in cerebral tissues is discussed.
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PMID:Human cerebral malaria: characterization of malarial antibodies in cerebrospinal fluid. 191 32

ELISA was evaluated for the serodiagnosis of Plasmodium vivax using homologous antigen. This was a crude fraction obtained after detergent (NP-40) lysis of human parasitized red blood cells. Antibodies of the classes IgM, IgG, IgA were determined in a pool of eleven sera from patients with P. vivax malaria. The protein A was introduced as secondary probe to screen P. vivax antibodies in 30 sera of patients harbouring a first episode of P. vivax malaria. There was a correlation of 93% with the parasitological diagnosis and the test resulted specific and reproducible.
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PMID:[The immunoenzymatic assay (ELISA) in the serodiagnosis of Plasmodium vivax]. 213 72

The magnitude of humoral response to soluble antigen extracted from Plasmodium falciparum schizonts and merozoites was assessed in 744 blood samples collected from different parts of India. In this study, parasitological and immunological data were considered for assessment of antibody during natural infections at various seasons. The antibody response has been measured by enzyme-immuno assay. Survey was done in all age groups. Overall antimalarial IgG level had started increasing after five years which shows that the rate of infection was high in the small age groups. Elevated level of IgG in populations indicates that the study area is undergoing a period prevalence of the disease. In most of the individuals with active infection, IgG and IgM levels were high. Positivity in IgM denoted the active transmission of malaria. Elevated levels of antigen specific IgA was observed in some cases but the mechanism is not yet understood. Presence of circulating immune complexes during acute infection shows the failure of detection of circulating free antibodies in some individuals. The significance of findings in relation to serological status in individuals exposed naturally to malaria has been discussed.
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PMID:The natural occurrence of circulating antibodies in populations of endemic malarious areas. 229 17

The sera of 55 Nigerian children (30 malarious and 25 healthy) were analysed for heterophile antibodies against normal sheep erythrocytes by the passive haemagglutination technique. Fluorescent antibodies to Plasmodium falciparum were quantified by the indirect immunofluorescence method while the three major immunoglobulins (IgG, IgA and IgM) were estimated by the radial immunodiffusion technique. An increasing age gradient was demonstrated in the heterophile antibody titres within the malarious and control groups, but there was no significant difference in the levels of immunoglobulins and malarial antibodies between the two groups. An indication of higher malarial antibody titre was only observed in the malarious group, particularly in late childhood. These results show an increasing level of heterophile antibodies with age. It is concluded that malarial antigens may play a contributory, but not a dominant role in the acquisition of heterophile antibodies. There is also a need to define the exact serum factors (antibody or non-antibody) which are associated with clinical immunity to malaria in Nigerian children.
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PMID:Immunity in malaria: II. Heterophile and malarial antibodies in acute Plasmodium falciparum infection. 255 Nov 66


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