This Article Full Text (PDF) Other Versions of this Article: IAI.01333-07v1 76/4/1748    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Akpogheneta, O. J. Articles by Conway, D. J. Search for Related Content PubMed PubMed Citation Articles by Akpogheneta, O. J. Articles by Conway, D. J.

 Previous Article  |  Next Article 

Infect. Immun. doi:10.1128/IAI.01333-07
Copyright (c) 2008, American Society for Microbiology and/or the Listed Authors/Institutions. All Rights Reserved.

Duration of naturally acquired antibody responses to blood stage Plasmodium falciparum is age dependent and antigen specific

Medical Research Council Laboratories, Fajara, The Gambia, Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, Keppel St, London WC1E 7HT, United Kingdom, Department of Immunology, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA

^* To whom correspondence should be addressed. Email: dconway{at}mrc.gm.

	Abstract

Naturally acquired antibody responses provide partial protection from clinical malaria, and blood stage vaccines under development aim to prime such responses. To investigate the determinants of antibody response longevity, serum IgG to several blood stage vaccine candidate antigens was examined in two cohorts of children aged up to 6 years during the dry seasons of 2003 and 2004 in The Gambia. The first cohort showed that most antibodies were lost within less than four months of the first sampling, if a persistent infection was not present, so the second year cohort involved sampling of individuals every 2 weeks over a three month period. Antibody responses in this second cohort were also influenced by persistent malaria infection, so analysis focused particularly on children who did not have parasites detected after the first time point. Antibodies to most antigens declined more slowly in the oldest age group of children (> 5 years old), and more rapidly in the youngest (< 3 years old). However, antibodies to merozoite surface protein 2 (MSP2) were shorter-lived and were not more persistent in older children. The age-specific and antigen-specific differences were not explained by different IgG subclass response profiles, indicating the probable importance of differential longevity of plasma cell populations rather than antibody molecules. It is likely that young children mostly have short-lived plasma cells and thus experience rapid decline in antibody levels, while older children have longer lasting antibody responses that depend on long-lived plasma cells.