AMA1 antibody cross-reactivity determined using competition ELISAs with combinations of three AMA1 alleles. Serum pools from PNG children (A) and Kenyan children (B) were tested in MACE with selected combinations of three AMA alleles as competitors. Each graph shows a particular combination of three competitor alleles tested against eight other AMA1 alleles. Specific combinations of three AMA1 alleles resulted in high level cross-reactivity against all other alleles, suggesting that immunization with these combinations could provide broad coverage against various AMA1 alleles. Combination E showed close to complete cross-reactivity against all tested AMA1 alleles in both human populations. For each figure the coating antigens used in experiments are those listed on the Y-axis, and the antigens used for competition are noted at the top of the figure. AMA1, apical membrane antigen 1; PNG, Papua New Guinea.