CD40L Culture Supports Differentiation of the HB-LTC–Derived CD19+ Cells Into IgM-Producing B Cells and Leads to Ig Isotype Switching
| Culture Conditions . | Ig Production (ng/mL) . | |||
|---|---|---|---|---|
| Day 14 . | Day 21 . | |||
| IgM . | IgG . | IgM . | IgG . | |
| CD34+ | ||||
| Medium | <0.5 | <0.1 | 0.9 | <0.1 |
| IL-2 | <0.5 | <0.1 | 0.6 | 0.3 |
| IL-4 | 5.0 | 0.2 | 54 | 7.3 |
| IL-10 | 14 | 0.9 | 22 | 8.1 |
| IL-2/IL-10 | 66 | 0.8 | 60 | 0.8 |
| IL-4/IL-10 | 111 | 9.7 | 176 | 78 |
| CD34+CD38− | ||||
| IL-4/IL-10 | 3.5 ± 2.2 | 23.1 ± 2.8 | ND | ND |
| Culture Conditions . | Ig Production (ng/mL) . | |||
|---|---|---|---|---|
| Day 14 . | Day 21 . | |||
| IgM . | IgG . | IgM . | IgG . | |
| CD34+ | ||||
| Medium | <0.5 | <0.1 | 0.9 | <0.1 |
| IL-2 | <0.5 | <0.1 | 0.6 | 0.3 |
| IL-4 | 5.0 | 0.2 | 54 | 7.3 |
| IL-10 | 14 | 0.9 | 22 | 8.1 |
| IL-2/IL-10 | 66 | 0.8 | 60 | 0.8 |
| IL-4/IL-10 | 111 | 9.7 | 176 | 78 |
| CD34+CD38− | ||||
| IL-4/IL-10 | 3.5 ± 2.2 | 23.1 ± 2.8 | ND | ND |
Representative experiment evaluating the time course of IgM production after transfer of HB-LTC CD19+ cells onto CD40L fibroblasts under alternative cytokine conditions. Secretion of IgM and IgG derived from CD34+CD38+ (top, 1 × 105 input CD19+ cells) and CD34+CD38− progenitors (bottom, 5 × 103 input CD19+ cells).
Abbreviation: ND, not determined.