FIG. 1.

Immune responses to HWC antigen according to H. pylori infection status and vaccine dose. Volunteers received an oral dose of either 2.5 × 10⁶, 2.5 × 10⁸, or 2.5 × 10¹⁰ inactivated HWC vaccine plus 25 μg of LT_R192G adjuvant on days 0, 14, and 28. Responses are expressed as the geometric mean (GM) titer or geometric mean number of ASCs per 10⁶ PBMC ± the back-transformed standard error measured prevaccination and postvaccination. Panels A, C, E, G, I, and K represent volunteers with no evidence of H. pylori infection (there were 3, 4, and 10 recipients of the 10⁶, 10⁸, and 10¹⁰ doses of HWC, respectively). Panels B, D, F, H, J, and L represent volunteers with subclinical H. pylori infection at baseline (there were 3, 3, and 8 recipients of the 10⁶, 10⁸, and 10¹⁰ doses of HWC, respectively). Comparisons of pre- and postvaccination titers: ∗, P < 0.05; ∗∗, P < 0.01; †, P = 0.06.