Fig. 4

The prevalence of IgG sub-class responses to rhoptry proteins. The reactive index (RI) of specific IgG sub-class responses to PvRALP1-Ecto and PvRhopH2 antigens in the plasma of P. vivax subjects at acute and during follow-up was detected by ELISA. a The comparative analysis of anti-IgG1, -IgG2, -IgG3, and -IgG4 specific to PvRALP1-Ecto and PvRhopH2 proteins in individuals with acute P. vivax malaria (AC, n = 39). The Kruskal–Wallis one-way ANOVA test was performed to compare the mean antibody levels of the difference IgG sub-classes. The horizontal line represents mean values ± SEM. b, c The anti-IgG1, -IgG2, IgG3 and -IgG4 responses to these two rhoptry proteins in 18 P. vivax subjects in the acute phase (AC) and convalescence phase (Conv.; 9 months post-infection). The comparisons of IgG sub-class response in the plasma of subjects during follow up (AC and Conv., n = 18) were done by Wilcoxon signed rank tests. Dashed line indicates the cut-off value (RI ≥ 1)