Table II.

IgM-expressing and Ig isotype-switched memory B cells enter division earlier than naive B cellsa

B CellsCD40L, IL-2, IL-10Mean ± SEM
Expt. 1Expt. 2Expt. 3
Naive85.6 ± 4.079.9 ± 0.4588.55 ± 1.884.72 ± 2.3
IgM memory62.0 ± 1.2055.7 ± 0.7676.52 ± 0.7164.77 ± 6.1
Switched memory53.3 ± 1.1054.1 ± 0.4575.17 ± 0.5060.86 ± 7.2
  • a Naive, IgM memory and isotype-switched memory B cells (5 × 104/125 μl/well) purified from different donors were cultured with CD40L, IL-2, and IL-10 for 5 days. At different times, the cultures were pulsed with [3H]thymidine and harvested 4 h later. The data were fitted to a log-normal distribution using Prism software. The values are the geometric means of the log-normal curves ± SE and represent the average ttfd.