[Biological activity of native and modified lipopolysaccharides of Pragia fontium].

Modified lipopolysaccharides (LPS) of Pragia fontium were obtained with germanium complexes (IV) of 2-aminobenzoylhydrazon of salicylic aldehyde (2-NH2-H2Bs), 2-hydroxybenzoylhydrazon salicylic aldehyde (2-OH-H2Bs) and nicotinoylhydrazon of salicylic aldehyde (H2Ns). The modification of LPS was confirmed by IR spectroscopy. Comparative investigations of pyrogenic activity of native and modified LPS showed, that only P. fontium 20125 LPS, modified by germanium complexes with 2-hydroxybenzoylhydrazon of salicylic aldehyde (2-OH-H2Bs) has lost the pyrogenic activity. In the homological reactions of double immunodiffusion in agar it was shown that all modified LPS unlike the native ones lose completely antigenic activity.