FIG 2.

S. sonnei antigen-specific antibody-secreting cell (ASC) counts after oral live S. sonnei vaccine candidate WRSS1 immunization. IgA, IgG, and IgM ASC counts (GMN ± SE) in 13 vaccinees and 6 placebo controls were determined on study days 0, 7, and 9 by ELISPOT assay. Vaccinees were subdivided into WRSS1 shedders (WS) (hatched bar; n = 9) and WRSS1 nonshedders (WNS) (white bar; n = 4). ASC counts in placebo controls (n = 6) are shown as a black bar. Statistical differences between WS and placebo groups were assessed using the Mann-Whitney test: P = 0.002 for both LPS- and INV-specific IgA ASC and P = 0.009 for both LPS- and INV-specific IgG ASC. In addition, a statistical difference between WS and WNS groups was assessed using the Mann-Whitney test: P = 0.006 for both LPS- and INV-specific IgA ASC.