Figure 8.

Intestinal IgA-secreting plasma cell numbers rapidly recover after depletion. (A) Mice were injected i.p. on two consecutive days with Bortezomib (Bz), lamina propria cells were isolated, and IgA-secreting plasma cells were quantified by ELISPOT on days 0, 2, 4, and 7 as indicated. Circles represent individual mice analyzed and pooled from two or more experiments, and horizontal lines indicate the mean. (B) Mice received BrdU with the drinking water starting 6 d before Bortezomib injection as indicated. Lamina propria cells were isolated, and the frequency of BrdU⁺ cells among CD138⁺IgA⁺ cells was determined by flow cytometry. Control mice did not receive BrdU. (C) SI tissue was embedded in paraffin, sectioned, and immunostained for IgA (green) and BrdU (red). Images are representative of at least five mice analyzed in two independent experiments. Boxed areas are shown at higher magnification in the bottom panels. Bars: (top) 50 µm; (bottom) 10 µm. (D) Plasma cell numbers rapidly recover after depletion in PP-deficient mice and splenectomized mice but not in CCR9^−/− mice. Mice received two consecutive injections of Bortezomib, and plasma cell numbers were quantified by ELISPOT in nondepleted mice and at days 0, 5, or 7 after depletion as depicted. Symbols represent individual mice pooled from at least two experiments. Horizontal lines indicate the mean. *, P < 0.05.