The human T cell lymphotropic virus type 1 (HTLV-I) is an oncogenic retrovirus that causes T-cell leukemia/lymphoma and chronic inflammatory syndromes, such as myelopathy/tropical spastic paraparesis. HTLV-I require cell to cell contact for transmission between individuals, but the mechanisms that facilitate this spread have been poorly understood. In the February 13
Igakura et al. used confocal microscopy to examine the distribution of HTLV-I Gag and Env (two surface glycoproteins) in fresh, unstimulated peripheral blood mononuclear cells (PBMCs). They observed that cell contact rapidly induced polarization of the cytoskeleton of the infected cell to the cell-cell junction. Next, HTLV-I core (Gag protein) complexes and the HTLV-I genome accumulated at the cell-cell junction and were transferred to the uninfected...