Format

Send to

Choose Destination
J Infect Dis. 2017 Oct 17;216(7):887-898. doi: 10.1093/infdis/jix370.

Declining Malaria Transmission Differentially Impacts the Maintenance of Humoral Immunity to Plasmodium falciparum in Children.

Author information

1
Kenya Medical Research Institute (KEMRI), Centre for Geographic Medicine, Coast, KEMRI-Wellcome Trust Research Programme, Kilifi.
2
Burnet Institute, Melbourne.
3
Department of Medicine, Royal Melbourne Hospital, University of Melbourne, Victoria, Australia.
4
Department of Infectious Diseases, Parasitology, Universitätsklinikum Heidelberg, Germany.
5
Department of Epidemiology and Preventive Medicine, Monash University.
6
Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Victoria, Australia.
7
Centre for Infectious Disease Research, Seattle, Washington.
8
Imperial College, London, United Kingdom.
9
Central Clinical School and Department of Microbiology, Monash University, Melbourne, Victoria, Australia.

Abstract

Background:

We investigated the poorly understood impact of declining malaria transmission on maintenance of antibodies to Plasmodium falciparum merozoite antigens and infected erythrocytes (IEs), including functional immunity.

Methods:

In a 3-year longitudinal cohort of 300 Kenyan children, antibodies to different AMA1 and MSP2 alleles of merozoites, IE surface antigens, and antibody functional activities were quantified.

Results:

Over a period in which malaria transmission declined markedly, AMA1 and MSP2 antibodies decreased substantially; estimated half-lives of antibody duration were 0.8 year and 1-3 years, respectively. However, 69%-74% of children maintained their seropositivity to AMA1 alleles and 42%-52% to MSP2 alleles. Levels and prevalence of antimerozoite antibodies were consistently associated with increasing age and concurrent parasitemia. Antibodies promoting opsonic phagocytosis of merozoites declined rapidly (half-life, 0.15 years). In contrast, complement-fixing antibodies to merozoites did not decline and antibodies to IE surface antigens expressing virulent phenotypes were much better maintained (half-life, 4-10 years).

Conclusions:

A decline in malaria transmission is associated with reduction in naturally acquired immunity. However, loss of immunity is not universal; some key functional responses and antibodies to IEs were better maintained and these may continue to provide some protection. Findings have implications for malaria surveillance and control measures and informing vaccine development.

KEYWORDS:

Africa; antibodies; complement; immunity; phagocytosis

PMID:
28973483
PMCID:
PMC5853596
DOI:
10.1093/infdis/jix370
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Silverchair Information Systems Icon for PubMed Central
Loading ...
Support Center