| Definition: |
A transitional stage B cell that expresses surface IgM and IgD, and CD62L. This cell type appears to be an anergic B cell that does not proliferate upon BCR signaling, is found in the spleen and lymph nodes, and has the phenotype surface IgM-positive, surface IgD-positive, CD21-positive, CD23-positive, CD62L-positive, and CD93-positive. This cell type has also been described as IgM-low, CD19-positive, B220-positive, AA4-positive, and CD23-positive (i.e. this cell-type is distinguished from T2 cells by surface expression of IgM). |