A short pulse with surrogate Ag enhances responsiveness of B cells to MIP-3β and BCA-1.

(A) The chemotactic response of CD38⁻ B cells was assessed at 2 time points: (1) at the end of a primary culture (T6) conducted with (white bars, T6 αIg) or without 10 μg/mL anti-Ig Abs (black bars, T6 CM) and (2) at the end of a secondary culture (T18) in which anti-Ig–pulsed B cells were cultured in the presence (gray bars, T18 CD40L) or absence of trimeric CD40L (hatched bars, T18 CM). The 4 chemokines were used at the same concentrations as for Figures 4 and 5. (B) Expression of CCR6, CCR7, CXCR4, and CXCR5 was analyzed after the primary culture with anti-Ig Abs (red line) and after the secondary cultures conducted with (black line) or without CD40L (blue line). The horizontal line indicates the negative threshold as determined by staining with an irrelevant isotype-matched Ab. (C) CD38⁻B cells were precultured for 6 hours in complete medium (white bars) or for 6 hours (black bars), 12 hours (hatched bars, αIg 12 hours), and 18 hours (gray bars, αIg 18 hours) with 10 μg/mL anti-Ig Abs before being analyzed for their chemotactic response to MIP-3α, MIP-3β, SDF-1α, and BCA-1. In panels A and C, the results are expressed as the mean ± SD of duplicate determinations. Representative of 1 experiment chosen among 3. CM indicates complete medium.