Germinal center exclusion of autoreactive B cells is defective in human systemic lupus erythematosus
J. Clin. Invest. Amedeo Cappione, et al. 115:3205 doi:10.1172/JCI24179 [Go to this article.]

Figure 3
Analysis of 9G4 cells in healthy spleens. (A) CD19⁺ spleen B cells were analyzed with IgD, CD38, CD27, and 9G4 antibodies as described above (n = 7 spleens). 9G4 B cells are very scarce within the GC and post-GC compartments (IgG and IgA memory). Representative results are shown as histograms. (B) Staining for IgM, IgD, CD21, and CD23 expression identified transitional (T1 and T2), follicular (FO), and MZ populations with a distribution similar to mouse B cells (12, 69). We identified an additional fraction composed of significant numbers of IgD⁺ cells, which represents a distinct subset of IgD⁺ MZ B cells (MZ*) (19). (C) Total spleen B cells were fractionated into MZ and follicular subsets as described above and further analyzed for the frequency of 9G4 B cells. The frequency of spleen follicular 9G4 cells was similar to the tonsil, and a lower but significant frequency was observed in the MZ fraction. (D) The majority of total and 9G4 MZ B cells express CD27. (E) The dearth of IgG and IgA 9G4 B cells was consistently documented in the spleen whether using total B cells or fractionated MZ B cells. (F) Dot plot analysis of total and 9G4 spleen B cells demonstrated that the vast majority of 9G4 B cells express an IgM⁺IgD⁺ phenotype. (G) Within the naive compartment, 9G4 B cells express significantly lower levels of surface IgM. MFI, mean fluorescence intensity.