FIGURE 9.

Transcriptional and recombinational status of the IgH chain locus in CL-01 cells at different stages of phenotypic differentiation. CL-01 cells were cultured with CD40L-293 cells, IL-4, and IL-10 for 5 days. Germline I_H-C_H and productive V_HDJ_H-C_H μ, γ1, γ2, γ3, γ4, α1, α2, and ε transcripts were amplified by PCR from cells at stages A (sIgM⁺sIgD⁺CD77⁺CD38⁺), B (sIgM^low/−sIgD^lowCD77⁺CD38⁺), C (sIgM^low/−sIgD⁻CD77⁺CD38⁺), D (sIgM^low/−sIgD⁺CD77⁺CD38⁺), and E (sIgM^low/−sIgD⁻CD77⁻CD38⁻), as defined in Figure 6. The different cell fractions were segregated on the basis of their surface expression of sIgD, CD38, and CD77. The results depicted here were obtained from one of two independent experiments yielding similar results.