Figure 1. IgA⁺ B cells dominate the germinal center reaction and are preferentially selected into the memory compartment.

(A-E) Steady state, co-housed, 8–12-week-old Iga^+/+ and Iga^−/− mice.

(A) Frozen PP sections from Iga^+/+ and Iga^−/− mice stained with immunohistochemistry antibodies against IgD (brown) and GL7 (blue). Scale bars, 200 μm.

(B) Representative plot of PP GC (GL7⁺ IgD⁻) and Foll (GL7⁻ IgD⁺) B cells in Iga^+/+ and Iga^−/− mice. Gated on live CD138⁻ B cells.

(C) PP GC B cells as percentage of activated (IgD⁻) B cells.

(D) PP Foll B cells as percentage of B cells.

(E) CD73⁺ CD80⁺ (DP) MemB, PCs as percentage of activated B cells.

(F) Iga^−/− mixed BM chimera experimental set up for (G-J).

(G) Representative CD45 staining on Foll and GC B cells in mixed BM chimeras.

(H) Ratio of frequency of CD45.2 GC B cells to CD45.2 Foll B cells in PP and mLN.

(I, J) Ratio of frequency of CD45.2 DP memB cells (I) or CD45.2 CD73⁻ CD80⁻ (DN) MemB cells (J) to CD45.2 Foll B cells in PP and mLN.

(K) Salmonella infection experimental setup in Iga^−/− mixed BM chimera for (L-M).

(L) Ratio of frequency of CD45.2 GC B cells to CD45.2 Foll B cells in PP and mLN of Salmonella infected chimeras.

(M) Ratio of frequency of CD45.2 DP MemB cells to CD45.2 Foll B cells in PP and mLN of Salmonella infected chimeras.

Data from at least 3 independent experiments with 2-3 mice per group (A-M). Each symbol represents one mouse. ns=not significant; ***p < 0.0005; ****p < 0.0001; Unpaired two-tailed Student’s t-test.

See also Figure S1.