Figure 1. Btk regulates anti-PtC B cell expansion and differentiation from B-1^intto B-1.

Splenocytes from 6-1, 6-1.Btk^lo, and 6-1.Btk-/- mice were stained with FITC-encapsulated liposomes, anti-CD5 PE or anti-CD43 PE, anti-B220 PerCP, and anti-CD23 biotin + streptavidin APC. A) The percentage of lymphocytes in each quadrant is indicated. B) Liposome-binding cells were gated and analyzed for expression of CD5, CD43, and CD23. B-2 cells (CD23+CD5- or CD23+CD43-) are in the upper left quadrant, B-1^int cells (CD23+CD5+ or CD23+CD43+) are in the upper right quadrant, and B-1 (CD23-CD5+ or CD23-CD43+) cells are in the lower right quadrant. Quadrants were defined using mice in which clear distinctions between populations were observed. The percentage of gated cells in each quadrant is indicated. Two individual 6-1.Btk^lo mice are shown in B) to reflect the range of variability seen in the differentiation state of anti-PtC B cells in these mice. Data in A) and B) are representative of 10 6-1, 10 6-1.Btk^lo and 5 6-1.Btk-/- mice. C) The number of splenocytes, B220+ cells, anti-PtC cells, and B-2, B-1^int, or B-1 within the anti-PtC population as defined by CD23 vs. CD5 or CD23 vs. CD43 are indicated. Each symbol (diamonds) represents an individual mouse. Bars represent the mean (n = 8-10). * = p < 0.05.