Table 2.
Expansion and differentiation of B lymphocytes are inversely related to the number of CD154 molecules per B lymphocyte.
| Proportion of positive cells (%)3 | Ig secretion (ng/106 cells/hr; mean ± SD)4 | ||||||
|---|---|---|---|---|---|---|---|
| Number of CD154 molecules/B cell1 | Expansion of CD19+ cells2(× 106 cells) | CD19+CD38+ | CD27++CD38+ | CD38++CD138+ | IgG | IgM | IgG:IgM |
| 1000 | 65 | 75 | 54 | 20 | 342 ± 48 | 12 ± 0.1 | 28 |
| 2000 | 267 | 57 | 32 | 8 | 178 ± 22 | 9 ± 0.1 | 20 |
| 5000 | 526 | 20 | 15 | 3 | 99 ± 6 | 13 ± 1 | 8 |
| 10000 | 686 | 3 | 2 | 1 | 50 ± 6 | 14 ± 1 | 4 |
| 25000 | 328 | < 1 | < 1 | 1 | 82 ± 6 | 90 ± 6 | 1 |
These results are representative of three independent experiments. Ig, immunoglobulin; SD, standard deviation.
CD19-purified peripheral B lymphocytes containing 30% CD27+ cells (375 000 cells/ml) were stimulated in the presence of interleukin (IL)-2, IL-4 and IL-10, along with CD154+ L4.5 cells adjusted so as to obtain the indicated numbers of CD154 molecules per B cell. L4.5low cells were used for 1000, 2000 and 5000 and L4.5high for 10 000 and 25 000 CD154 molecules per B cell.
B-cell expansion was evaluated on day 14.
The percentages of CD19+ CD38+ and CD27++ CD38+ cells were determined on day 8, and the percentage of CD38++ CD138+ cells was determined on day 13.
IgG and IgM secretion from day 14–15 was measured by enzyme-linked immunosorbent assay (ELISA).