Structure of the RESA gene of<i>Piasmodium falciparum</i>

SUMMARYMechanisms responsible for the increase in malaria susceptibility during pregnancy, and in particular during the first pregnancy, have not been elucidated. T and B cell responses to leucoagglutinin, bacille Calmette-Guérin (BCG) and to six Plasmodium falciparum antigens were longitudinally investigated in 33 pregnant women during their first pregnancy, after delivery, and during second pregnancy. Parasitological data obtained from the same women during and after the first pregnancy demonstrated the higher risk of P. falciparum infection during this pregnancy. Plasma levels of antibodies to Pf155/ RESA were lower during pregnancy than after delivery. Conversely, antibodies to P. falciparum asexual blood stages were higher during pregnancy than after delivery, suggesting that during pregnancy the regulation of antibody production may be variously impaired depending upon the antigens. The most striking finding of the present study is the impairment of the IL-2 cellular response during the first pregnancy. Conversely, proliferative responses, as well as IL-4 and interferon-gamma (IFN-g) responses, were either unaffected or moderately enhanced. No difference in humoral and cellular responses was observed between first and second pregnancy. The impairment of the IL-2 responses involved the response to malaria peptides and proteins, as well as the response to non-malarial antigens and to the mitogen leucoagglutinin. Thus, the alteration of malaria immunity might rather fall into the general frame of the depression of cellular immunity during pregnancy than involve a specific malaria phenomenon.

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“…944-959 (EENVEHDA) 4 T þ B * Position according to [17]. † The sequences are given in one-letter code.…”

Section: In Vitro Production Of Ifn-g Il-2 and Il-4mentioning

confidence: 99%

Immune response to Plasmodium falciparum antigens in Cameroonian primigravidae: evolution after delivery and during second pregnancy

Fiévet

Cot

Ringwald

et al. 1997

Clinical and Experimental Immunology

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“…The synthetic peptides NDKKAKKYDTQDVVGYl (aa 850 66), representing a common allelic form ofa non-repeated antigenic sequence from the blood stage antigen Pfl55/RESA ( [20]; L, Aslund. manuscript in preparation) and the repeat SVTEEIAEEDKSVIEEAV (aa 2-19) from antigen Pf332 [21] were synthesized and purified to homogeneity by high-pressure liquid chromatography as described [22].…”

Section: Antigen Synthetic Peptidesmentioning

confidence: 99%

IgE elevation and IgE anti-malarial antibodies in Plasmodium falciparum malaria; association of high IgE levels with cerebral malaria

Perlmann

Helmby

Hagstedt

et al. 1994

Clinical and Experimental Immunology

113

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SUMMARYIn the course of studying immunoregulation in human Plasmodium falciparum malaria we have investigated IgE levels and IgE anti-plasmodial antibodies in children and adults from areas of high malaria endeniicity in both Africa and Asia. On average, 85% of all donors had significantly elevated levels of total IgE. A fraction of the IgE had anti-plasmodial activity as revealed by ELISA with lysates of infected crythrocytes as antigen. Using synthetic peptides representing antigenic regions of two major plasmodial blood stage antigens, IgE antibody concentrations ranged from 5 to 15 ng/ml serum for each of the peptides. On average, the concentrations of the corresponding IgG antibodies were x500-I000 higher. Immunobiotting of parasite lysates showed that most donors had IgE antibodies against one or several of a restricted number of plasmodial polypeptides, with antibodies against an antigen of moi.wt 45 kD already being present in all donors at an early age. Donors having IgE antibodies to particular antigens also frequently had corresponding IgG4 arffWvdies. reflecting underlying IL-4-dependent cellular mechanisms controlling formation of these isotypes. As infection with other parasites sueh as helminths is known lo induce IgE elevation, the results do not prove that plasmodial infections were the primary cause of IgE induction. However, the importance of plasmodial infection for IgE elevation was supported by the finding of significantly higher levels of IgE., but not of IgG, in children with cerebral malaria compared with patients with uneomplicated disease.

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“…The molecule of Pfl 55/RESA includes amino acid repeated sequences [11], a feature of numerous Plasmodium antigens. Dominant B cell epitopes and some T cell epitopes are located within these repeats.…”

Section: Introductionmentioning

confidence: 99%

Quantification of antibody-secreting lymphocytes that react with Pf155/RESA fromPlasmodium falciparum: an ELISPOT assay for field studies

Fiévet

Chougnet

Dubois

et al. 1993

Clinical and Experimental Immunology

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SUMMARYWe have adapted the enzyme-linked immunospot assay (ELISPOT) to enumerate the cells from Plasmodium falciparum-primed donors that produce IgG in vitro in response to malaria antigens. In vitro activation of cell cultures with two synthetic peptides (EENVEHDA)4, and (LGRSGGDIIKMQTL) corresponding to immunodominant T cell epitopes of the ring-infected erythrocyte surface antigen (Pf 155/RESA) gave specific antibody-secreting cells (ASC) in five and six of the 15 P, falciparum-primed donors from Cameroon. Antibodies produced after a stimulation by synthetic peptides reacted also with total parasite proteins. However, crude P, falciparum antigen did not trigger a higher number of cells than did synthetic peptides. The absence of significant relation between the presence of sera antibodies and in vitro ASC against the same peptide suggests that the kinetics of circulating primed lymphocytes and antibodies are different. We evaluated 004-0-29% of peripheral blood B cells to be the frequency of memory cells specific to a single Pfl 55/RESA epitope in these donors. This study suggests that the ELISPOT assay should permit the analysis of B cell responses to malarial antigens at the single-cell level and its applicability to epidemiological field studies. This assay should be well suited to the identification of T helper epitopes capable of inducing the production of antibodies by human B cells, and will constitute an important tool for the selection of immunogens to be included in a subunit vaccine.

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Structure of the RESA gene ofPiasmodium falciparum

Cited by 181 publications

References 22 publications

Immune response to Plasmodium falciparum antigens in Cameroonian primigravidae: evolution after delivery and during second pregnancy

Immune response to Plasmodium falciparum antigens in Cameroonian primigravidae: evolution after delivery and during second pregnancy

IgE elevation and IgE anti-malarial antibodies in Plasmodium falciparum malaria; association of high IgE levels with cerebral malaria

Quantification of antibody-secreting lymphocytes that react with Pf155/RESA fromPlasmodium falciparum: an ELISPOT assay for field studies

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