Figure 3.

Intestinal IgA antibody responses and immunologic memory in cholera after oral immunization or infection. (A) IgA antibody responses to cholera toxin (B subunit) and LPS O antigen in intestinal lavage from adult Bangladeshi volunteers after cholera disease and/or immunizations with a B-subunit/whole-cell cholera vaccine that was administered orally (PO) or intramuscularly (IM) at an interval of 28 days. Two oral vaccine doses (in which the B subunit amounts were either 2.5 or 0.5 mg) induced antitoxin and anti-LPS intestinal IgA responses that were fully comparable to those measured after disease; in contrast, the IM route was ineffective. Adjusted from [16]. (B) Intestinal immune response kinetics in Swedish healthy adults after a first and second primary immunization with oral B subunit/whole-cell cholera vaccine (Dukoral) and after a single booster dose 5.5 months later; immune responses were examined as specific anti-B subunit antibody-secreting cells (ASC) in mononuclear cells (MNC) that were isolated from duodenal mucosal biopsies at various time points. Adapted from [22]. (C) Long-lasting immunologic memory to cholera B subunit found in Swedish adult volunteers for at least 9–14 years after an initial two-dose immunization regimen with the Dukoral OCV; this was demonstrated by giving a single booster dose at different times after the primary immunizations and finding intestine-derived IgA responses that were superior to those seen after a first dose in concomitantly first-time immunized volunteers and fully comparable in magnitude and kinetics to the second-dose responses in the latter individuals. Adapted from [23].