Mevastatin inhibits CD43 redistribution without inhibiting cell shape polarization.

Purified CD 4⁺ T cells were incubated with 50 μM mevastatin for 18 hours and then activated with beads coated with anti-CD3 and anti-CD28. The cells were fixed and stained for CD43 as described in “Materials and methods.” (A) An example of T cells untreated with mevastatin and activated with beads at the same time as mevastatin-treated cells. Two of the 3 cells conjugated with the bead on the photograph redistributed the CD43 away from cell-bead interaction site. (B) An example of cells treated with mevastatin. Although cell shape polarization was similar to the untreated cells, CD43 was not redistributed away from the cell-bead contact site. The arrows indicate location of the beads. (C) Quantitation of CD43 polarization in cell shape polarized cells treated with mevastatin. The bars represent the average percentage of cells with polarization of CD43 out of cells that have polarized shapes in conjunction with bead contact. Three slides, with 15 to 42 shape-polarized cells per slide, were counted and averaged and the error bars represent 1 SD. The difference between the mevastatin and mevastatin with mevalonic acid lactone groups was significant at P < .03. Three additional experiments, comparing mevastatin-treated and control groups, were averaged and showed a difference between the groups that was significant at P < .002. (D) Mevastatin-treated cells were conjugated with APC-like beads, fixed, permeabilized, and stained with FITC-labeled cholera toxin B subunit to detect rafts. (E-F) Purified DO.11.10 TCR transgenic CD4⁺ T cells were purified and combined with UT139.B2 APCs pulsed with the ovalbumin antigenic peptide, OVA_323-339. The cells were fixed and stained for CD43 as described in “Materials and methods.” (E) T cell–APC interactions without mevastatin treatment. (F) T cell–APC interactions after T-cell treatment with 50 μM mevastatin for 18 hours. Similar results have been observed in 2 experiments. Magnification × 1000.