Abstract |
Naturally acquired protective immunity to Plasmodium falciparum malaria takes years to develop. It relies mainly on Abs, particularly IgG specific for Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) proteins on the infected erythrocyte surface. It is only partially understood why acquisition of clinical protection takes years to develop, but it probably involves a range of immune-evasive parasite features, not least of which are PfEMP1 polymorphism and clonal variation. Parasite-induced subversion of immunological memory and expansion of "atypical" memory B cells may also contribute. In this first, to our knowledge, longitudinal study of its kind, we measured B cell subset composition, as well as PfEMP1-specific Ab levels and memory B cell frequencies, in Ghanaian women followed from early pregnancy up to 1 y after delivery. Cell phenotypes and Ag-specific B cell function were assessed three times during and after pregnancy. Levels of IgG specific for pregnancy-restricted, VAR2CSA-type PfEMP1 increased markedly during pregnancy and declined after delivery, whereas IgG levels specific for two PfEMP1 proteins not restricted to pregnancy did not. Changes in VAR2CSA-specific memory B cell frequencies showed typical primary memory induction among primigravidae and recall expansion among multigravidae, followed by contraction postpartum in all. No systematic changes in the frequencies of memory B cells specific for the two other PfEMP1 proteins were identified. The B cell subset analysis confirmed earlier reports of high atypical memory B cell frequencies among residents of P. falciparum-endemic areas, and indicated an additional effect of pregnancy. Our study provides new knowledge regarding immunity to P. falciparum malaria and underpins efforts to develop PfEMP1-based vaccines against this disease.
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Authors | Paulina Ampomah, Liz Stevenson, Michael F Ofori, Lea Barfod, Lars Hviid |
Journal | Journal of immunology (Baltimore, Md. : 1950)
(J Immunol)
Vol. 192
Issue 11
Pg. 5236-44
(Jun 01 2014)
ISSN: 1550-6606 [Electronic] United States |
PMID | 24760153
(Publication Type: Clinical Trial, Journal Article, Research Support, Non-U.S. Gov't)
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Copyright | Copyright © 2014 by The American Association of Immunologists, Inc. |
Chemical References |
- Antibodies, Protozoan
- Immunoglobulin G
- Protozoan Proteins
- erythrocyte membrane protein 1, Plasmodium falciparum
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Topics |
- Adult
- Antibodies, Protozoan
(blood, immunology)
- B-Lymphocytes
(immunology, metabolism)
- Erythrocyte Membrane
(immunology, metabolism, parasitology)
- Female
- Ghana
- Humans
- Immunoglobulin G
(blood, immunology)
- Immunologic Memory
- Malaria, Falciparum
(blood, immunology)
- Plasmodium falciparum
(immunology, metabolism)
- Pregnancy
- Pregnancy Complications, Parasitic
(blood, immunology)
- Protozoan Proteins
(immunology, metabolism)
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