Polarization of the MTOC and Gag p19 toward an antibody-coated latex bead. The MTOC was polarized toward beads coated with anti-CD11a antibody in HTLV-1–infected and uninfected CD4⁺ T cells after 1 hour of incubation. Tubulin α is green, stained using Fluorescein (FITC), original magnification × 400. If the MTOC was polarized, then invariably Gag p19 (red, stained with Alexa Fluor 568) was also polarized toward an antibody-coated bead. Similar polarization of both the MTOC and Gag p19 was induced by latex beads coated with either anti-CD2, CD3, CD18 (LFA-1), CD25 (IL-2Rα), CD28, CD50 (ICAM-3), CD54 (ICAM-1), or CD58 (LFA-3).