Immunogenicity

Immunoglobulin G (IgG) against GMZ2, as well as the GLURP_27-500 and MSP3_212-380, was measured by an enzyme-linked immunosorbent assay (ELISA) in plasma collected at baseline and on D84. GLURP and MSP3 fragments contained in GMZ2 were expressed in Escherichia coli. IgG concentrations were derived from fitting the optical density values of serial plasma dilutions. ELISA and data analysis were done as previously described [24–26], with minor modifications: plasma was diluted in phosphate-buffered saline, 3% non-fat milk, and 0.1% Tween 20, and a peroxidase-conjugated, goat, anti-human IgG (Invitrogen) was used at a 1:65 000 dilution. Pooled sera from lifelong–malaria- exposed adults were used as a positive control, and a pool of malaria-naive European adults served as a negative control.