Fig. 5.

Apoptosis induction during secondary gene rearrangement of normal peripheral blood B cells. a. Intracytoplasmic RAG expression and apoptosis induction of normal κ+ B cells stimulated with SAC + IL-2. Cytoplasmic RAG2 expression and annexin V binding of the B cells were studied by two colour immunofluorescence analysis. RAG2 protein expression was evident at day 3. At days 3 and 4, annexin V+ apoptotic B cells have emerged only in RAG2+ B cells. All the annexin V+ B cells expressed RAG2 simultaneously. The results shown were representatives of 6 independent experiments. b. Intracytoplasmic RAG expression and caspase-3 activity of normal κ+ B cells stimulated with SAC + IL-2. Cytoplasmic RAG2 expression and caspase-3 activity of the B cells were studied by two colour immunofluorescence analysis. At days 3 and 4, caspase-3-activated apoptotic B cells have emerged only in RAG2+ B cells. The results shown were representatives of 3 independent experiments. c. Cell surface λ chain expression and caspase-3 activity of the B cells were studied by two colour immunofluorescence analysis. At day 3, normal κ+ B cells stimulated with SAC + IL-2 were examined and caspase-3-activated cells have emerged only in λ-negative B cells.