There is evidence that the development of certain autoimmune diseases may be associated with a bacterial or viral infection that stimulates production of antibodies and immune cells called T cells, which are targeted against bacterial proteins that closely resemble "self" proteins, leading to crossreactivity with healthy tissues. Dr. Gennaro De Libero from University Hospital in Basel, Switzerland, and colleagues identified a different mechanism where bacterial infections promote activation of T cells that recognize molecules called glycosphingolipids (GSL) that are present in bacteria and humans. The researchers show that infection with some bacteria or even just exposure to pieces of the outer wall of the bacteria results in an increase in "self" GSL synthesis by cells that promote the immune response and subsequent stimulation of autoreactive GSL-specific T cells.
"Collectively, these findings suggest that recognition of self by infection is an important mechanism leading to autoreactive T cell activation and, possibly, participates in the pathogenesis of some autoimmune diseases, such as MS and GBS, in which the anti-GSL T cell response may be important," writes Dr. De Libero. The authors suggest that although the autoreactive T cells may play a useful role in promoting the immune response to infection, in the absence of infection the GSL autoreactive T cells might seek out the abundant "self" GSLs that can be found in the nervous system, resulting in degradation of brain and nerve tissue as is seen in patients with MS and GBS.
The researchers include Gennaro De Libero, Hans-Jürgen Gober, Emmanuel Rossy, Sebastiano Sansano, Regine Landmann, and Lucia Mori of the University Hospital, Basel; Anthony P. Moran and Martina M. Prendergast of the National University of Ireland, Galway; Alexander Tonevitsky of the Institute for Genetics of Microorganisms, Moscow; Abdijapar Shamshiev (University Hospital, Basel) presently at Swiss Federal Institute of Technology Zurich; Olga Chelnokova of University Hospital, Basel and Institute for Genetics of Microorganisms, Moscow; Zurich Zaima Mazorra (University Hospital, Basel) presently at Center of Molecular Immunology, Havana; and Silvia Vendetti and Alessandra Sacchi of the Istituto "Lazzaro Spallanzani," Rome. This work was supported by the International Association for the Promotion of Cooperation with scientists from the New Independent States (NIS) of the Former Soviet Union (INTAS); the Swiss National Fund; the Human Frontier Science Program; the Swiss Multiple Sclerosis Society; the Italian Public Health Ministry; and by the Irish Health Research Board.
De Libero, G., Moran, A.P., Gober, H.-J., Rossy, E., Shamshiev, A., Chelnokova, o., Mazorra, Z., Vendetti, S., Sacchi, A., Prendergast, M.M., Sansano, S., Tonevitsky, A., Landmann, R., and Mori, L. (2005). Bacterial Infections Promote T Cell Recognition of Self-Glycolipids. DOI 10.1016/j.immuni.2005.04.013. Publishing in Immunity, Vol. 22, June, 2005, pages 763–772. http://www.immunity.com/
Journal
Immunity