Figure 1.

Kinetics and magnitude of antibody responses against bacterial antigens in scrub typhus patients. (A) IgG titers specific to whole bacterial antigens were measured by an immunofluorescence assay (IFA) using plasma samples from 64 scrub typhus patients. Patients were divided into four groups based on the time after recovery from the disease; Y0: within 2 weeks after recovery (n=21), Y1–Y3: 1–3 year(s) after recovery (n=20, 11 and 12, respectively). (B) Kinetic responses of IgG antibodies against ScaA or TSA56 were assessed by enzyme-linked immunosorbent assay (ELISA). The patient groups are the same as in A. The mean titer of the antibody responses (A, B) are indicated as red lines, and statistical analysis was performed using one-way analysis of variance (ANOVA) followed by the Newman–Keuls t-test for comparisons of the values among different groups (*P<0.05; **P<0.01; ***P<0.001). (C) Correlations of the IFA and ELISA titers were assessed by linear regression analysis (red lines), and the r² and P values are shown in the graphs.