Figure 9

Analysis of antibody cross-reactivity within amino sequence cluster groups of AMA1 alleles. A) Classification of the 11 AMA1 alleles into the sequence cluster groups described by Duan et al. [35] (based on the sequence including domains I, II and III (excluding the prodomain)). B) Antibody cross-reactivity measured by competition ELISA for AMA1 alleles within each cluster group. Alleles within each group were compared pairwise with each other. C) Level of antibody cross-reactivity between AMA1 alleles within the same cluster group, compared to cross-reactivity between AMA1 alleles in different clusters - a total of 88 pair-wise comparisons of cross-reactivity was made. The median cross-reactivity of alleles (bar) within the same sequence cluster group was only slightly higher compared to cross-reactivity of alleles from different clusters (p = 0.012; median cross-reactivity was 48.5% for same cluster and 37% for different cluster). Data on antibody cross-reactivity were obtained from testing PNG children. AMA1, apical membrane antigen 1; PNG, Papua New Guinea.