Deciphering the genetic basis of Moraxella catarrhalis complement resistance: Gene expression analysis of Moraxella catarrhalis BBH18 upon exposure to normal human serum.

The complement system is an important part of the innate defense against invading pathogens. The ability to resist complement-mediated killing is considered to be an important virulence trait for the human-restricted respiratory tract pathogen M. catarrhalis, as most disease-associated M. catarrhalis isolates are complement-resistant. Here we studied the molecular basis of M. catarrhalis complement-resistance by transcriptome profiling upon exposure to 10% normal human serum (NHS). After 1h exposure of M. catarrhalis BBH18 to 10% NHS (n = 5) or the NHS dilution buffer alone (control, n = 5), total RNA was isolated and labeled cDNA was generated according to standard Nimblegen gene expression array protocols and hybridized to 4x72K Nimblegen M. catarrhalis expression arrays for read-out.