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Malar J. 2019 Jan 18;18(1):11. doi: 10.1186/s12936-019-2647-8.

The impact of early life exposure to Plasmodium falciparum on the development of naturally acquired immunity to malaria in young Malawian children.

Author information

1
The Department of Medicine (RMH), Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, 3000, Australia.
2
Department of Zoology, University of Dhaka, Dhaka, 1000, Bangladesh.
3
Burnet Institute, Melbourne, VIC, 3004, Australia.
4
Department of Microbiology and Central Clinical School, Monash University, Melbourne, VIC, 3800, Australia.
5
School of Public Health and Family Medicine, University of Malawi, Blantyre 3, Malawi.
6
Faculty of Medicine and Life Sciences, University of Tampere and Tampere University Hospital, 33100, Tampere, Finland.
7
Research and Development, Maternal, Newborn and Adolescent Health, World Health Organization, Geneva 27, 1211, Switzerland.
8
The Department of Medicine (RMH), Peter Doherty Institute for Infection and Immunity, The University of Melbourne, Melbourne, VIC, 3000, Australia. sroger@unimelb.edu.au.

Abstract

BACKGROUND:

Antibodies targeting malaria blood-stage antigens are important targets of naturally acquired immunity, and may act as valuable biomarkers of malaria exposure.

METHODS:

Six-hundred and one young Malawian children from a randomized trial of prenatal nutrient supplementation with iron and folic acid or pre- and postnatal multiple micronutrients or lipid-based nutrient supplements were followed up weekly at home and febrile episodes were investigated for malaria from birth to 18 months of age. Antibodies were measured for 601 children against merozoite surface proteins (MSP1 19kD, MSP2), erythrocyte binding antigen 175 (EBA175), reticulocyte binding protein homologue 2 (Rh2A9), schizont extract and variant surface antigens expressed by Plasmodium falciparum-infected erythrocytes (IE) at 18 months of age. The antibody measurement data was related to concurrent malaria infection and to documented episodes of clinical malaria.

RESULTS:

At 18 months of age, antibodies were significantly higher among parasitaemic than aparasitaemic children. Antibody levels against MSP1 19kD, MSP2, schizont extract, and IE variant surface antigens were significantly higher in children who had documented episodes of malaria than in children who did not. Antibody levels did not differ between children with single or multiple malaria episodes before 18 months, nor between children who had malaria before 6 months of age or between 6 and 18 months.

CONCLUSIONS:

Antibodies to merozoite and IE surface antigens increased following infection in early childhood, but neither age at first infection nor number of malaria episodes substantially affected antibody acquisition. These findings have implications for malaria surveillance during early childhood in the context of elimination. Trials registration Clinical Trials Registration: NCT01239693 (Date of registration: 11-10-2010). URL: http://www.ilins.org.

KEYWORDS:

Episodes; Merozoite antigens; Nutrient supplements; Randomized controlled trial; Seroprevalence; Variant surface antigens

PMID:
30658632
PMCID:
PMC6339377
DOI:
10.1186/s12936-019-2647-8
[Indexed for MEDLINE]
Free PMC Article

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