CD4+ or CD8+ T cells isolated from a HAM/TSP patient were allowed to form conjugates with T cells from a healthy uninfected donor for 120 min: in addition to accumulation of Gag p19 staining at the cell-cell junction, there was frequent Gag p19 staining in the cells derived from the uninfected donor [32,35,41]. The gene discussed is CD4; the disease is tropical spastic paraparesis.