Loh E, Kugelberg E, Tracy A, Zhang Q, Gollan B, Ewles H, Chalmers R, Pelicic V, Tang CM.
Nature
doi:10.1038/nature12616
Abstract
Neisseria meningitidis has several strategies to evade complement-mediated killing, and these contribute to its ability to cause septicaemic disease and meningitis. However, the meningococcus is primarily an obligate commensal of the human nasopharynx, and it is unclear why the bacterium has evolved exquisite mechanisms to avoid host immunity. Here we demonstrate that mechanisms of meningococcal immune evasion and resistance against complement increase in response to an increase in ambient temperature. We have identified three independent RNA thermosensors located in the 5′ untranslated regions of genes necessary for capsule biosynthesis, the expression of factor H binding protein, and sialylation of lipopolysaccharide, which are essential for meningococcal resistance against immune killing1, 2. Therefore increased temperature (which occurs during inflammation) acts as a ‘danger signal’ for the meningococcus, enhancing its defence against human immune killing. Infection with viral pathogens, such as influenza, leads to inflammation in the nasopharynx with an increased temperature and recruitment of immune effectors3, 4. Thermoregulation of immune defence could offer an adaptive advantage to the meningococcus during co-infection with other pathogens, and promote the emergence of virulence in an otherwise commensal bacterium.
Contributions
E.L., E.K., A.T., Q.Z., B.G. and H.E. performed the experiments and analysed the data. R.C. and V.P. oversaw the DNA foot-printing and construction of transcription factor mutants. C.M.T. provided overall direction, and wrote the manuscript with input from E.L., E.K. and R.C., and the other authors.
Posted on Wednesday 9th October 2013