Figure 2. Splenic B-cell phenotypes in B6.56R/+ and B6.56R/56R Tg mice.

Splenocytes from 9–12 mo old B6.56R/+ (TOP) and B6.56R/56R mice (BOTTOM) were analyzed by flow cytometry for the expression of B220 vs IgM^a, IgM^b, CD86 and I-A^b, respectively. IgM^a B-cells were further divided arbitrarily into three groups as demarcated by the dotted lines: IgM^a-high B-cells, IgM^a-medium B-cells and IgM^a-low B-cells; the frequencies of B-cells with different surface IgM^a levels are summarized in Table 1. The boxes drawn indicate the expanded population of B-cells in B6.56R/56R Tg mice that were B220^int, I-Ab^int, CD86^hi, relative to the B6.56R/+ controls. The profiles shown are representative of data obtained from 8 mice per stain.