Fig. 1.

Reduced proliferation of naive but not memory CD4⁺ T cells in the presence of calcitriol-primed naive B cells. Carboxyfluorescein diacetate N-succinimidylester (CFSE)-labelled and proliferated T cells after 7 days co-culture with anti-CD40 (1 μg/ml) and interleukin (IL)-4 (10 ng/ml) preactivated (solid line, open bar) or preactivated and calcitriol-primed B cells (filled area, open bars). (a) Toxic shock syndrome toxin 1 (TSST-1)-induced proliferation of naive and memory T cells in the presence of naive or memory B cells. (b) T cells activated with TSST-1. (c) T cells activated with anti-CD3. Dot-blots are gated on living T lymphocytes of a representative donor. (d) Graph bars summarized results of five independent experiments and represent difference in % of progenitor T cells in the presence of activated B cells, set as 100% (open bar). Data are shown as mean ± standard deviation. *P ≤ 0·05; **P ≤ 0·01 considered significant.