Figure 2. IgA is required for efficient plasma cell homing to the intestinal lamina propria.

(A) Isotypes of gut-homing (α4β7⁺ CCR9⁺) and non-gut homing PCs from PPs of WT mice treated with FTY-720 for seven days. IgG is defined as IgG1⁺ or IgG2b⁺.

(B) Representative immunofluorescence of small intestinal villi from Aicda^cre/+ Rosa26^{Stop-tdTomato} Iga^+/+, Aicda^cre/+ Rosa26^{Stop-tdTomato} Iga^−/−, Aicda^cre/cre Rosa26^{Stop-tdTomato} mice stained with DAPI (gray) and tdTomato (red). Scale bars, 100 μm.

(C) Quantification of multiple images as in (B). Number of tdTom⁺ cells per villi.

(D) Isotype staining in Aicda^cre/+ Rosa26^{Stop-tdTomato} Iga^+/+ and Aicda^cre/+ Rosa26^{Stop-tdTomato} Iga^−/− lamina propria. Gated on CD98⁺ B220⁻ CD4⁻ PCs.

(E, F) Ratio of frequency of CD45.2 gut-homing PCs to CD45.2 Foll B cells from PPs (E) or mLN (F) of mixed BM chimeras.

(G, H) Ratio of frequency of CD45.2 non-gut-homing PCs to CD45.2 Foll B cells from PPs (G) or mLN (H) of mixed BM chimeras.

(I) Aicda^cre/+ Rosa26^{Stop-tdTomato} Iga^+/+ mixed BM chimera experimental set up for (J-L).

(J) Representative immunofluorescence of small intestinal villi stained for DAPI (gray), IgA (cyan), and tdTomato (red) in WT: Aicda^cre Rosa26^{Stop-tdTomato} Iga^+/+ or Iga^−/− mixed BM chimeras. Scale bars, 100 μm.

(K, L) Quantification of multiple images as in (J). Number of IgA⁺ cells (K) or tdTom⁺ cells (L) per villi.

Data from 2 independent experiments with 2-3 mice per group (A, C, D, K, L). Data from at least 3 independent experiments with 3-5 mice per group (E-H). Each symbol represents one mouse. (C, K, L) Each symbol represents one villi with at least 5 villi quantified per image.

ns=not significant, *p < 0.005; ##p < 0.001; ***, ###p < 0.0005; ****p < 0.0001. Unpaired two-tailed Student’s t-test in E-H, K, L. One way ANOVA was used in A(*), C(*), and D(#) .

See also Figure S2.