MATS ELISA values were calculated as antigen-specific relative potencies compared with MenB reference strains expressing each vaccine antigen [19, 22]. The data were compiled and quality controlled by Novartis Vaccines and Diagnostics. MATS-PBT prediction of 4CMenB strain coverage Predicted coverage using MATS-PBT was calculated as described previously [19, 22, 23]. The presence of at least one

antigen with a relative potency greater than its MATS-PBT relative potency value (0.021 for fHbp, 0.294 for NHBA and 0.009 for NadA) or the presence of PorA VR2 1.4 (matched to the OMV-NZ component of 4CMenB) was considered to be sufficient for a strain to be covered by 4CMenB. Strains that did not meet these criteria were considered INK-128 not covered. Estimates of the 95% confidence intervals (95% CI) for the MATS-PBTs were derived on the basis of overall assay repeatability and reproducibility (0.014-0.031 for fHbp, 0.169-0.511 for NHBA, 0.004-0.019 for NadA) [22]. These intervals were used to define the 95% strain coverage interval by 4CMenB. Results and discussion Prevalence and diversity of the tested isolates The tested isolates belonged to several clonal complexes (cc). Among the 148 isolates tested

by MATS, 66 (44.6%) belonged to cc162, which is the predominant lineage in Greece, followed by cc269 (33/148; 22.3%), cc41/44 (n = 11/46; 24%) and cc32 (18/148; 12.1%) each respectively, Roxadustat price while 15 isolates (15/148; 10.1%) belonged to other clonal complexes (cc) (cc60, cc35, cc461, cc212) or to sequence types (STs) not currently assigned to any clonal complex (Figure  2). The proportion of clonal complexes in Greece was different as compared with other European Countries, based on data recently published by Vogel and colleagues in the Euro-5 study [23] ZD1839 this was particularly true in the case of cc162, which was 44.6% in Greece but which represented only 2.5% in other European Countries,

at least based on combined data from Germany, France, Italy, United Kingdom and Norway and on preliminary data from Spain and Czech Republic. The percentage of isolates belonging to cc269 was 22.3% in Greece, higher than in the rest of Europe, however it was quite comparable with data from United Kingdom. On the contrary, the proportion of cc41/44 isolates in Greece, 12.1% was slightly lower with respect to other European Countries. Figure 2 Most frequent clonal complexes among the 148 Greek isolates (1999–2010). The percentages of isolates within each clonal complex that were covered by at least the indicated protein are displayed. Greek isolates, including those belonging to the same clonal complex, showed several combinations of variable regions 1 and 2 (VR1 and VR2) in PorA. The OMV component of the vaccine contains PorA subtype P1.7-2, 4. 11 isolates among the 148 analysed (7%) showed this subtype. However, the immune response induced by PorA has been shown to specifically target the VR2 4 epitope [34].