PKCβ deficiency results in a reduction in plasma cell numbers and abrogates spontaneous germinal cell (GC) formation in Sle mice. A, Flow cytometric analysis of splenocytes from 5–6-month-old PKCβ-deficient Sle mice. Cells were stained with the indicated antibodies. The encircled areas show spleen plasmablasts (CD138highB220+) and plasma cells (CD138highB220low/negative). Results are representative of 3 independent experiments. B, Expression of IgG anti-dsDNA plasma cells (antibody-secreting cells [ASCs]) in 1 × 106 cells from spleen or bone marrow, as determined by enzyme-linked immunospot assay. Bars show the mean ± SD. ** = P < 0.01. C, Representative immunofluorescence images of spontaneous GC (CD19+GL7+) formation in spleen sections. Spleen sections from the indicated mouse strains were stained with GL7 (green), CD3 (red), and CD19 (blue). Original magnification × 20. D, Representative results of flow cytometric analysis of GC cells (CD19+CD95+GL7+) in the indicated mouse strains. Results shown in A, B, and C were obtained from the same group of mice. See Figure 1 for other definitions.