Correlation of high levels of antibodies to multiple pre-erythrocytic Plasmodium falciparum antigens and protection from infection.
High levels of antibodies to multiple antigens may be more strongly associated with protection from infection than antibodies to a single antigen. Antibody-associated protection against Plasmodium falciparum infection was assessed in a cohort of 68 adults living in an area of holoendemic malaria in Kenya. Antibodies to the pre-erythrocytic antigens circumsporozoite protein (CSP), liver-stage antigen-1 (LSA-1), thrombospondin-related adhesive protein (TRAP), and blood-stage antigens apical membrane antigen-1 (AMA-1), erythrocyte binding antigen-175 (EBA-175), and merozoite surface protein 1 (MSP-1) were tested. Peptides were used for CSP (NANP repeat) and LSA-1 (central repeat), and recombinant antigens were used for TRAP (aa D(48)-K(394)), AMA-1 (ectodomain, non-glycosylated), EBA-175 (non-glycosylated), and MSP-1 (MSP-1(19)). Weekly microscopy testing for P. falciparum infection was performed over a 12-week period after drug-mediated clearance of P. falciparum parasitemia. Individuals with high levels of IgG antibodies (> 2 arbitrary units) to CSP, LSA-1, and TRAP had a 57% decrease in the risk of infection (95% confidence interval = 20-77%, P = 0.016). This decreased risk remained significant after adjustment for age, prior parasitemia, bed net use, sickle cell trait, and village of residence. In contrast, protection against infection did not correlate with high levels of IgG antibodies to blood-stage antigens or IgM antibodies to pre-erythrocytic or blood-stage antigens. High levels of IgG antibodies to CSP, LSA-1, and TRAP may be useful immune correlates of protection against P. falciparum infection in malaria-endemic populations.
John
Chandy C
CC
Center for Global Health and Diseases, Rainbow Center for International Child Health, Division of Pediatric Infectious Diseases, Case Western Reserve University, Cleveland, Ohio, USA. chandy.john@case.edu
Moormann
Ann M
AM
Pregibon
Daniel C
DC
Sumba
Peter Odada
PO
McHugh
Marilyn M
MM
Narum
David L
DL
Lanar
David E
DE
Schluchter
Mark D
MD
Kazura
James W
JW
D000328:Adult; D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood*; D000953:Antigens, Protozoan / Q000276:immunology*; D004912:Erythrocytes / Q000469:parasitology*; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood*; D016778:Malaria, Falciparum / Q000097:blood* / Q000276:immunology* / Q000517:prevention & control; D008297:Male; D010963:Plasmodium falciparum / Q000235:genetics / Q000276:immunology*; D016133:Polymerase Chain Reaction; D015800:Protozoan Proteins / Q000276:immunology; D012008:Recurrence
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D015800:Protozoan Proteins; C041595:circumsporozoite protein, Protozoan