Figure 2

Analysis of immune response against iRBC membrane protein extracts using sera from non-exposed individuals (NEI), briefly exposed individuals (BEI) or highly exposed individuals (HEI) to malaria. IgG immune profiles from 4 NEI, 6 BEI and 2 HEI revealed by immunoblotting against erythrocyte membrane protein extracts from RBC (A), or iRBC (B) are presented. Two human sera, "Ctrl NEI (-)" and "Ctrl HEI (+)", loaded on each blot, were used as controls for antibody revelation and migration quality. MW: molecular weight, kDa: kiloDalton. (C) Comparative analysis of the antigenic bands number recognized by sera from NEI, BEI and HEI against RBC and iRBC membrane protein extracts. For this quantitative analysis, significant differences are indicated for each group tested between the two membrane protein extracts (p < 0.05, Mann-Whitney test). The line within the box represents the mean number of antigenic bands recognized by each sera group. The boundaries of the box indicate the 25th and 75th percentiles. Whiskers above and below the box indicate the maximum and minimum values. (D) Frequency of iRBC membrane antigenic protein bands detected by NEI and BEI. Analysis of IgG profiles using diversity database software (Biorad) allowed us to exhibit 8 antigenic bands from iRBC membrane protein extracts statistically significant (Fisher exact test, *p < 0.05; **p < 0.01, ***p < 0.001) between NEI and BEI groups. Only protein bands significantly different between NEI and BEI and detected by at least 20 percent of the individuals from a group were indicated. (E) These antigenic bands are indicated on a diagram using Roman numeral numbers, and their corresponding molecular weights are indicated in brackets.