pneumonia D39 in 50 μl PBS was instilled into the nares under deep

general halothane anaesthesia 28 days after the final colonising dose [5], [15] and [16]. Animals were culled by exsanguination from the femoral artery under pentobarbital anaesthesia. Broncheo-alveolar lavage fluid (BALF) was collected by cannulating the exposed trachea and washing the airways three times serially with 1 ml sterile PBS. Lungs were collected aseptically into ice-cold PBS, minced and homogenised with sterile PBS as previously [5] and [17]. For survival experiments, animals were monitored and culled when exhibiting previously defined features of terminal disease [16]. Antibodies specific to antigens in different S. pneumoniae strains were measured by whole cell ELISA using established methods as previously described [8]. Briefly, S. pneumoniae were grown to late log-phase, washed and resuspended in PBS to OD580 1.0. 96-well plates were Ulixertinib order coated with this bacterial suspension, refrigerated overnight, then blocked with PBS 1% BSA

prior to use. Sera were diluted in PBS 1% BSA before addition and binding to bacterial antigens detected with anti-mouse secondary antibodies conjugated to alkaline phosphatase (Sigma). To measure capsule-specific antibodies, plates were coated with type 2 purified capsular polysaccharide (CPS) at 10 μg/ml (LGC Promochem). To increase assay specificity, sera were pre-incubated with cell wall polysaccharide (Statens Serum Institut) and type 22F capsular polysaccharide (LGC Promochem) as previously [11]. Development of ELISAs proceeded as for whole cell ELISAs. To determine Onalespib concentration the relative contribution of CPS binding towards

PD184352 (CI-1040) the total binding observed in whole cell ELISA, sera were pre-incubated in PBS/1% BSA with increasing concentrations of soluble type 2 CPS up to 100 μg/ml for 30 min at RT, prior to assay in whole cell ELISA as above. Antibody responses to multiple protein antigens were measured using a multiplex flow cytometry Luminex assay based on S. pneumoniae proteins conjugated to xMAP beads, as previously [11]. Recombinant TIGR4-, D39-, or serotype 23 strain-derived proteins were conjugated to xMAP beads (Luminex) [18]. Combined beads (3000 per antigen) were incubated with 10% or 1% serum in PBS–1% bovine serum albumin and then with goat anti-mouse IgG-phycoerythrin (Jackson ImmunoResearch). IgG binding was subsequently assessed using a Bioplex instrument (Bio-Rad Labs) and Bio-Plex Manager software. Data are presented as log10 MFIs of IgG binding to each bead type, after subtraction of the results for blank beads. There was no binding to proteins using serum from control mice. Bacterial loads were compared at specific time-points by Mann–Whitney U-test. Antibody levels were compared between groups of mice by two-tailed Student’s t-test. Survival of challenged mice was compared by the log rank test. P values <0.05 were considered significant.