CD34/GFP double-positive cells emerging in response to CID treatment have a B-lymphoid phenotype.

(A) Cytospin of sorted cells showing a lymphoid morphology (× 1000). (B) Scatter plots of CD34/GFP double-positive cells from the marrow of the second dog (red dots) demonstrate staining with an antibody to terminal deoxynucleotidyl transferase, but no staining with an isotype control antibody. (C) The time course of GFP-positive cells among peripheral blood B cells in response to CID treatment in the second dog. The black rectangle indicates the period of AP20187 treatment. (D) Homing of GFP-positive B cells to a popliteal lymph node. Shown is the deep pole of a germinal center in a popliteal lymph node (100 × objective) stained with a rabbit polyclonal antibody directed against GFP. Black arrows indicate immunoblasts, black arrowheads indicate apoptotic figures, and white arrows indicate mitotic figures, all of which are typical of a germinal center reaction. Brownish stain indicates GFP positivity.