COMPARATIVE STRUCTURAL STUDY OF THE MANNOSYLATED-LIPOARABINOMANNANS FROM MYCOBACTERIUM-BOVIS BCG VACCINE STRAINS - CHARACTERIZATION AND LOCALIZATION OF SUCCINATES

In order to investigate the molecular basis of the differences observe d in the immunogenicity of various BCG vaccines, which mag play a majo r role in BCG vaccination efficiency, the presence and the partial str ucture of the lipoarabinomannans (LAMs) were investigated in four diff erent BCG strains (Pasteur, Glaxo, Copenhagen, and Japanese strains), According to their cell-wall extraction mode, the LAMs were subdivided into two classes, namely, parietal LAMs and cellular LAMs. From a str uctural point of view, the cellular LAMs and parietal LAMs both belong to the ManLAM class since the relevant structural features, described for ManLAMs, that is, the phosphatidyl-myo-Ins anchor and the manno-o ligosaccharide caps were characterized, In addition, thanks to NMR exp eriments realized on the native ManLAMs, we prove the existence of suc cinyl groups and we determine their location on the C-2 of the 3,5-di- O-alpha-D-Araf units. The average number of succinyl groups was estima ted at one and four per ManLAMs molecule for Glaxo and Japanese vaccin es, respectively, and two for Pasteur and Copenhagen strains.