FIGURE 3.

Effect of acute febrile malaria on expression of 9G4⁺ B cells and 9G4⁺ IgG. (A) Percent of B cells that are 9G4⁺ in B cell subsets (as in Fig. 1C) in the PBMCs of 6 year old Malian children in May (Pre), just prior to the malaria transmission season and seven days following their first acute febrile malaria episodes (Acute). Mean and SEM are shown. Statistical comparisons were by Student’s T-test. (B) Total IgG in plasma from individuals prior to the malaria transmission season and 14 days after their first acute febrile malaria episode with subject data paired. (C) 9G4⁺-IgG levels in plasma samples from the individuals in B. Statistical comparisons were by Student’s T-test. (* = p-value < 0.05; ** = p-value < 0.005; *** = p-value < 0.0005) (D) The ratio of the levels of 9G4⁺ IgG (in C) to the levels of total IgG (in B). (E) Arbitrary ELISA units (AU) for MSP-1₄₂- and AMA1-specific IgG with age. Linear regressions and 95% confidence interval are shown. Both slopes are significantly greater than 0 (P value < 0.005). (F) 9G4+-IgG levels with age in the same subjects in D. Linear regression is shown with 95% confidence interval. The slope is not significantly different than 0.