Enhanced binding of plasma cells to VCAM-1 through α4 integrins.
(A) Binding of plasma cells and IgM+ B cells to VCAM-1/L cells was analyzed using a low shear rocking adhesion assay. Where indicated, cells were incubated with 50 nM PMA for 15 minutes prior to the assay. (B) Plasma cell binding to untransfected L cells (striped bars), or in the presence of 2 μg of the anti-α4blocking antibody R1-2 (empty bars). Data are represented as the mean number of bound cells per field ± SD for 20 fields of view. A representative experiment of 3 is shown. The asterisk indicates statistically different (P < .05) from part A, the corresponding group (with or without PMA) of plasma cells; or in part B, plasma cells binding to VCAM-1 in the absence of blocking mAb. (C) The relative binding of plasma cells and Jurkat cells. The mean ± SD of 2 independent experiments is shown.
