Antigen-specific B cells in tissues after oral typhoid vaccination

Six human subjects who were to receive elective bowel surgery for a variety of diseases were vaccinated with the oral typhoid vaccine, Ty21a. Intestinal tissue (ileum in two, large intestine in four) removed 7-26 days after the first dose of vaccine was examined for the presence and distribution of antigen-specific B cells. This was compared with intestinal tissue derived from two unvaccinated controls. A number of B cell differentiation antigens were also assessed on these cells by immunofluorescence using dual-labelling. Antigen-specific cells were found randomly distributed in the lamina propria of all the vaccinated subjects in low frequency (6 +/- 0.5 to 37 +/- 31 [mean +/- s.e.m.] antigen specific cells/10 mm2 of tissue). The lymphocyte differentiation antigens CD45RA, CD45RO, L-selectin, CD-11a CD-38, CD-44 and VLA-4 were all found on antigen-specific cells, but no particular pattern was recognizable in this small series of six subjects with different disease processes affecting the intestine.