Do antibody responses to malaria vaccine candidates influenced by the level of malaria transmission protect from malaria?
OBJECTIVE
To examine whether the humoural response to malaria vaccine candidate antigens, Plasmodium falciparum [circumsporozoite repetitive sequence (NANP)(5) GLURP fragments (R0 and R2) and MSP3] varies with the level of malaria transmission and to determine whether the antibodies (IgG) present at the beginning of the malaria transmission season protect against clinical malaria.


METHODS
Cross-sectional surveys were conducted to measure antibody response before, at the peak and at the end of the transmission season in children aged 6 months to 10 years in two villages with different levels of malaria transmission. A cohort study was performed to estimate the incidence of clinical malaria.


RESULTS
Antibodies to these antigens showed different seasonal patterns. IgG concentrations to any of the four antigens were higher in the village with high entomological inoculation rate. Multivariate analysis of combined data from the two villages indicated that children who were classified as responders to the selected antigens were at lower risk of clinical malaria than children classified as non-responders [(NANP)(5) (incidence rate ratio (IRR) = 0.65, 95% CI: 0.46-0.92; P = 0.016), R0 (IRR = 0.69, 95% CI: 0.48-0.97; P = 0.032), R2 (IRR = 0.73, 95% CI: 0.50-1.06; P = 0.09), MSP3 (IRR = 0.52, 95% CI: 0.32-0.85; P = 0.009)]. Fitting a model with all four antibody responses showed that MSP3 looked the best malaria vaccine candidate (IRR = 0.63; 95% CI: 0.38-1.05; P = 0.08).


CONCLUSIONS
Antibody levels to the four antigens are affected by the intensity of malaria transmission and associated with protection against clinical malaria. It is worthwhile investing in the development of these antigens as potential malaria vaccine candidates.
Nebie
I
I
Centre National de Recherche et de Formation sur le paludisme, Ouagadougou, Burkina Faso. issanebie.cnlp@fasonet.bf
Tiono
A B
AB
Diallo
D A
DA
Samandoulougou
S
S
Diarra
A
A
Konate
A T
AT
Cuzin-Ouattara
N
N
Theisen
M
M
Corradin
G
G
Cousens
S
S
Ouattara
A S
AS
Ilboudo-Sanogo
E
E
Sirima
B S
BS
D000818:Animals; D000913:Antibodies, Protozoan / Q000097:blood / Q000276:immunology*; D000953:Antigens, Protozoan / Q000276:immunology*; D002050:Burkina Faso; D002648:Child; D002675:Child, Preschool; D003430:Cross-Sectional Studies; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000276:immunology; D007223:Infant; D017780:Malaria Vaccines / Q000276:immunology*; D016778:Malaria, Falciparum / Q000276:immunology / Q000469:parasitology / Q000517:prevention & control* / Q000635:transmission*; D010963:Plasmodium falciparum / Q000276:immunology; D015800:Protozoan Proteins / Q000276:immunology; D012621:Seasons
D000913:Antibodies, Protozoan; D000953:Antigens, Protozoan; D007074:Immunoglobulin G; D017780:Malaria Vaccines; D015800:Protozoan Proteins; C089133:merozoite surface protein 3, Plasmodium