Fig 3.

Percentages of H. ducreyi that were associated with (top) or internalized by (bottom) macrophages. (A) 35000HP and 35000HP-RSM208 (neuA mutant) grown on chocolate agar plates with and without Neu5Ac supplementation were incubated with macrophages at an MOI of 10:1 for 30 min without opsonization, followed by 30 min of treatment with gentamicin. Percent association or internalization was calculated as the ratio of bacteria recovered without or with gentamicin treatment to initial CFU added. The values represent the means ± SDs from assays done with macrophages from 5 (top) or 6 (bottom) donors. There were no significant differences among the groups in either assay. (B) 35000HP and 35000HP-RSM208 were grown on chocolate agar plates with Neu5Ac supplementation and were either not opsonized or opsonized with 100% autologous serum prior to performance of the assays outlined for panel A. The values in both panels represent the means ± SDs from assays done with macrophages from 4 donors. There were no significant differences between the neuA mutant and the parent strain in either assay.