Patterns of cross-reactivity of AMA1 antibodies in children at two different times. Each graph (A-E) shows antibody cross-reactivity between AMA1 alleles in a cohort of Kenyan children (pooled serum) sampled at two time points, in 2002 and 2004. Each allele was tested in competition ELISA against four other AMA1 alleles and cross-reactivity was determined. The pattern of cross-reactivity and allele-specificity of naturally acquired antibodies of children were very similar at the two time-points; antibodies from older children (2004) tended to have slightly higher cross-reactivity than two years earlier (2002) (P <0.05). For each figure (A-E), the competing antigens used in experiments are those listed on the Y-axis. AMA1, apical membrane antigen 1.