RV: A new immune pathway triggered by bacterial infections

Fuente: INRA - Press
Expuesto el: martes, 14 de agosto de 2012 12:46
Autor: Press
Asunto: A new immune pathway triggered by bacterial infections

 

Press Info item. 14/08/2012   Researchers from INRA, Institut Pasteur, INSERM, Université Paris Descartes and Freiburg University have shown for the first time that lambda interferons, actors in immunity, are produced during infections caused by Gram-positive bacteria that can give rise to listeriosis, staphylococcosis and tuberculosis. These findings open new perspectives in our understanding of innate immune response mechanisms in epithelial tissues such as the intestine, lungs and placenta.

Interferons belong to a particular group of proteins called cytokines that are naturally present in our bodies and which serve as messengers between different cells in order to aid the immune system in fighting against infections and tumours.  Until now, the interferons known for their involvement in bacterial infections were of types I (IFN-a, IFN-b) and II (IFN-g).  Now, a third type of interferon, or interferon λ, has been associated with viral diseases. After demonstrating that type III interferons (λ) were secreted by cultured epithelial cells infected with Listeria bacteria, the scientists then evidenced their induction in the placenta of gestating mice during listeriosis.  And in pregnant women, Listeria preferentially infects the placenta (principally made up of epithelial cells).  The scientists also identified other bacterial species capable of triggering the expression of these type III interferons, such as staphylococci and mycobacteria.  On the other hand, bacteria such as Salmonella, Shigella and Chlamydia had little effect on the synthesis of these molecules.  In light of these findings, the scientists are now addressing the reason for the specific ability of certain Gram+ bacteria to trigger the expression of interferons λ in epithelial cells.  Further research is now necessary to determine the role of these cytokines in the persistence of bacteria in epithelial cells. This work suggest the possibility that λ interferon may be of value for the diagnosis and treatment of chronic infections such as tuberculosis, hospital-acquired diseases caused by staphylococci, or listerosis in pregnant women or immunodepressed patients. Reference Hélène Bierne et al. Activation of Type III Interferon Genes by Pathogenic Bacteria in Infected Epithelial cells and Mouse Placenta. PLoS ONE, 14 juin 2012, DOI: 10.1371/journal.pone.0039080

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