FIG 3  .

Western blots of proteinase K extracts of NTHi strain 2019 grown on sRMPI medium in the presence of 100μM Neu5Ac (lane A), the same extract treated with sialidase (lane B), and strain 2019 grown on sRMPI medium in the absence of Neu5Ac (lane C). As can be seen when the terminal N-acetyllactosamine is occupied by Neu5Ac, neither MAb 3F11 nor 6E4 binds NTHi LOS in the presence of Neu5Ac. Loss of the Neu5Ac after sialidase treatment exposes the terminal N-acetyllactosamine, resulting in MAb 3F11 binding, MAb 6E4 does not bind in this instance. When NTHi is grown in the absence of Neu5Ac, the majority of the acetyllactosamine is occupied by KDO, which is indicated by the strong MAb 6E4 binding and the weaker MAb 3F11 binding.