B-cell responses to pregnancy-restricted and -unrestricted Plasmodium falciparum erythrocyte membrane protein 1 antigens in Ghanaian women naturally exposed to malaria parasites

dc.contributor.authorAmpomah, P.
dc.contributor.authorStevenson, L.
dc.contributor.authorOfori, M.F.
dc.contributor.authorBarfod, L.
dc.contributor.authorHviid, L.
dc.date.accessioned2018-11-21T16:49:41Z
dc.date.available2018-11-21T16:49:41Z
dc.date.issued2014
dc.description.abstractProtective immunity to Plasmodium falciparum malaria acquired after natural exposure is largely antibody mediated. IgG-specific P. falciparum EMP1 (PfEMP1) proteins on the infected erythrocyte surface are particularly important. The transient antibody responses and the slowly acquired protective immunity probably reflect the clonal antigenic variation and allelic polymorphism of PfEMP1. However, it is likely that other immune-evasive mechanisms are also involved, such as interference with formation and maintenance of immunological memory. We measured PfEMP1-specific antibody levels by enzyme-linked immunosorbent assay (ELISA) and memory B-cell frequencies by enzyme-linked immunosorbent spot (ELISPOT) assay in a cohort of P. falciparum-exposed nonpregnant Ghanaian women. The antigens used were a VAR2CSA-type PfEMP1 (IT4VAR04) with expression restricted to parasites infecting the placenta, as well as two commonly recognized PfEMP1 proteins (HB3VAR06 and IT4VAR60) implicated in rosetting and not pregnancy restricted. This enabled, for the first time, a direct comparison in the same individuals of immune responses specific for a clinically important parasite antigen expressed only during well-defined periods (pregnancy) to responses specific for comparable antigens expressed independent of pregnancy. Our data indicate that PfEMP1- specific B-cell memory is adequately acquired even when antigen exposure is infrequent (e.g., VAR2CSA-type PfEMP1). Furthermore, immunological memory specific for VAR2CSA-type PfEMP1 can be maintained for many years without antigen reexposure and after circulating antigen-specific IgG has disappeared. The study provides evidence that natural exposure to P. falciparum leads to formation of durable B-cell immunity to clinically important PfEMP1 antigens. This has encouraging implications for current efforts to develop PfEMP1-based vaccines. © 2014, American Society for Microbiology.en_US
dc.identifier.other10.1128/IAI.01514-13
dc.identifier.urihttp://ugspace.ug.edu.gh/handle/123456789/25674
dc.language.isoenen_US
dc.publisherInfection and Immunityen_US
dc.subjectB-cellen_US
dc.subjectPlasmodium falciparumen_US
dc.subjecterythrocyte membraneen_US
dc.subjectprotein 1 antigensen_US
dc.subjectGhanaen_US
dc.subjectmalaria parasitesen_US
dc.titleB-cell responses to pregnancy-restricted and -unrestricted Plasmodium falciparum erythrocyte membrane protein 1 antigens in Ghanaian women naturally exposed to malaria parasitesen_US
dc.typeArticleen_US

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