IgG recognition by sera from malaria-exposed individuals. (a) CS2 (b) CS2KO9 and (c) E8B IE were incubated with sera from Malawian men, primigravid and multigravid women (cohort 1). (d) CS2 and (e) CS2KO9 IE were incubated with sera from men, primigravid and multigravid women from Madang, Papua New Guinea (cohort 2). (f) CS2 and (g) CS2KO IE were incubated with sera from men, primigravid, and multigravid women from Malawi (cohort 3). Data presented are mean fluorescence intensities (MFI) for individual samples. Bars indicate median MFI for the population. Significant differences in responses were found as follows: (a) cohort 1, CS2: men and primigravidae (PG; p < 0.0001), men and multigravidae (MG; p < 0.0001) and PG and MG (p = 0.001); (b) cohort 1, CS2KO9: men and PG (p = 0.0011), men and MG (p < 0.0001), and PG and MG (p = 0.047); (c) cohort 1, E8B: men and MG (p = 0.047) (f) cohort 3, CS2, men and PG (p = 0.001), men and MG (p = 0.0013).