Fig. 6: Bridging efficacy study with LukAB CC8Δ10C and LukAB RARPR-33 showing improved toxin neutralization for LukAB RARPR-33.

Serum obtained from the study described in Fig. 5 was used in toxin neutralization assays. The fold increase in IC50 toxin neutralization titers between day 0 (three weeks post the third immunization, before challenge) and day -63 (pre-immunization) is shown as the geometric mean for each group against each LukAB variant. The different experimental groups are color coded. Statistically significant differences between LukAB CC8Δ10C and LukAB RARPR-33 are indicated. The differences between LukAB CC8Δ10C and LukAB RARPR-33 compared to the AS01B group are not shown in the Figure but were statistically significant P < 0.05, (except for LukAB CC8Δ10C, CC5 neutralization). Statistical differences were determined using a Tobit model with a Bonferroni post-hoc test to correct for multiple comparisons. TNA, toxin neutralization assay (in vitro). AS01B Adjuvant System AS01B, CC clonal complex, LukAB leukocidin AB, SpA Staphylococcal protein A.