Several laboratories showed that the molecular mechanism of T cell polarization and immunological synapse formation could be subverted by viruses that infect T lymphocytes, such as HIV-1 or HTLV-1, to better spread from cell to cell. The cell-cell contact through which these viruses spread was called the virological synapse, because of its common characteristics with immunological synapses (Reviewed in Pais-Correia et al., 2007, Thoulouze and Alcover, 2010, 2011). We have recently shown the HTLV-1 cell-to-cell transmission occurs via extracellular viral assemblies that resemble in structure, composition and function to bacterial biofilms. These « viral biofilms » are induced by the virus and formed by clusters of infectious viral particles held together and to the cell surface by a carbohydrate-rich extracellular matrix components and linker proteins (Figure 1).
Removal of the « HTLV-1 biofilm » from the surface of virus-producing T cells strongly impairs the ability of HTLV-1-infected cells to infect other cells (Pais-Correia et al, 2010, Thoulouze and Alcover, 2010, 2011). Our findings unveil a novel virus transmission mechanism (Figure 2), which can be utilized by other viruses and be the target for new antiviral strategies.
A. M. Pais-Correia, V. Robbiati, R. Lasserre, C. Inizan, M. Caillet, A. Alcover and M. I. Thoulouze, in collaboration with the Unit of Oncogenic Virus Epidemiology and Physiopathology (A. Gessain and col) and the Imagopole, Institut Pasteur.