Ig secretion by transitional B-cell subsets
| . | Ig concentration, ng/mL . | |||
|---|---|---|---|---|
| CD21lo transitional . | CD21hi transitional . | Naive . | Memory . | |
| IgM | ||||
| Unstimulated | < 5 | < 5 | < 5 | 5.3 ± 1.4 |
| CpG | 15.5 ± 6.7 | 25.8 ± 19.3 | 33.3 ± 10.3 | 1205 ± 165 |
| + IL-21 | 4.6 ± 2.8 | 22.3 ± 17.8 | 18.7 ± 4.5 | 1083 ± 549 |
| CD40L | 9.1 ± 1.2 | 6.5 ± 3.0 | 17.2 ± 5.9 | 184 ± 63 |
| + IL-21 | 8232 ± 1498 | 8128 ± 781 | 13 815 ± 1228 | 30 318 ± 9380 |
| + CpG | 1030 ± 142 | 1826 ± 438 | 4817 ± 2282 | 7784 ± 3834 |
| + CpG + IL-21 | 13 742 ± 3354 | 16 567 ± 5956 | 20 879 ± 3776 | 30 034 ± 324 |
| IgG | ||||
| Unstimulated | < 5 | < 5 | < 5 | < 5 |
| CpG | < 5 | < 5 | < 5 | 39.0 ± 20.1 |
| + IL-21 | < 5 | < 5 | < 5 | 148.8 ± 94.7 |
| CD40L | < 5 | < 5 | < 5 | 10.8 ± 5.8 |
| + IL-21 | 645 ± 97 | 904 ± 465 | 620 ± 204 | 2853 ± 568 |
| + CpG | 7.8 ± 3.4 | 20.1 ± 8.1 | 54.6 ± 13.6 | 114.8 ± 20.9 |
| + CpG + IL-21 | 762 ± 215 | 983 ± 372 | 1082 ± 206 | 2950 ± 1245 |
| IgA | ||||
| Unstimulated | < 5 | < 5 | < 5 | < 5 |
| CpG | < 5 | < 5 | < 5 | 585 ± 296 |
| + IL-21 | < 5 | 7.2 ± 4.2 | 10.3 ± 6.4 | 638 ± 184 |
| CD40L | < 5 | < 5 | < 5 | 90 ± 68 |
| + IL-21 | 612 ± 368 | 719 ± 224 | 644 ± 312 | 19 898 ± 5429 |
| + CpG | 5.8 ± 3.1 | 36.3 ± 30.6 | 686 ± 285 | 6270 ± 2883 |
| + CpG + IL-21 | 585 ± 205 | 1051 ± 288 | 1919 ± 714 | 49 607 ± 22 512 |
| . | Ig concentration, ng/mL . | |||
|---|---|---|---|---|
| CD21lo transitional . | CD21hi transitional . | Naive . | Memory . | |
| IgM | ||||
| Unstimulated | < 5 | < 5 | < 5 | 5.3 ± 1.4 |
| CpG | 15.5 ± 6.7 | 25.8 ± 19.3 | 33.3 ± 10.3 | 1205 ± 165 |
| + IL-21 | 4.6 ± 2.8 | 22.3 ± 17.8 | 18.7 ± 4.5 | 1083 ± 549 |
| CD40L | 9.1 ± 1.2 | 6.5 ± 3.0 | 17.2 ± 5.9 | 184 ± 63 |
| + IL-21 | 8232 ± 1498 | 8128 ± 781 | 13 815 ± 1228 | 30 318 ± 9380 |
| + CpG | 1030 ± 142 | 1826 ± 438 | 4817 ± 2282 | 7784 ± 3834 |
| + CpG + IL-21 | 13 742 ± 3354 | 16 567 ± 5956 | 20 879 ± 3776 | 30 034 ± 324 |
| IgG | ||||
| Unstimulated | < 5 | < 5 | < 5 | < 5 |
| CpG | < 5 | < 5 | < 5 | 39.0 ± 20.1 |
| + IL-21 | < 5 | < 5 | < 5 | 148.8 ± 94.7 |
| CD40L | < 5 | < 5 | < 5 | 10.8 ± 5.8 |
| + IL-21 | 645 ± 97 | 904 ± 465 | 620 ± 204 | 2853 ± 568 |
| + CpG | 7.8 ± 3.4 | 20.1 ± 8.1 | 54.6 ± 13.6 | 114.8 ± 20.9 |
| + CpG + IL-21 | 762 ± 215 | 983 ± 372 | 1082 ± 206 | 2950 ± 1245 |
| IgA | ||||
| Unstimulated | < 5 | < 5 | < 5 | < 5 |
| CpG | < 5 | < 5 | < 5 | 585 ± 296 |
| + IL-21 | < 5 | 7.2 ± 4.2 | 10.3 ± 6.4 | 638 ± 184 |
| CD40L | < 5 | < 5 | < 5 | 90 ± 68 |
| + IL-21 | 612 ± 368 | 719 ± 224 | 644 ± 312 | 19 898 ± 5429 |
| + CpG | 5.8 ± 3.1 | 36.3 ± 30.6 | 686 ± 285 | 6270 ± 2883 |
| + CpG + IL-21 | 585 ± 205 | 1051 ± 288 | 1919 ± 714 | 49 607 ± 22 512 |
B-cell subsets were purified from the PB of different healthy donors and then cultured (5-10 × 103 cells per 200 μL per well) in the absence or presence of CpG (10 ng/mL), CD40L, or CpG plus CD40L without or with IL-21. After 12 days, supernatants were harvested and the amount of secreted IgM, IgG, and IgA was determined by Ig heavy chain-specific ELISAs. The results represent the mean ± SEM of 3 independent experiments.