Somatic Antigens of Pseudomonas aeruginosa

Abstract

On mild acid degradation of Pseudomonas aeruginosa O:3(a),c, O:3a,d,e and O:3(a),d,f lipopolysaccharides O‐specific polysaccharides were isolated. The trisaccharide repeating units of O:3(a),c and O:3a,d,e polysaccharides contained 2‐acetamido‐2,6‐dideoxy‐d‐galactose and 2,3‐(1‐acetyl‐2‐methyl‐2‐imidazolino‐5,4)‐2,3‐dideoxy‐d‐mannuronic acid, which were identified previously as the constituents of P. aeruginosa O:3a,b and O:3a,d O‐specific polysaccharides, as well as 2,3‐diacetamido‐2,3‐dideoxy‐l‐guluronic acid, which has never before been found in nature. The last monosaccharide was identified without being isolated in the free state, by means of ¹³C nuclear magnetic resonance spectroscopy. The structures of O:3(a),c and O:3a,d,e polysaccharides were established by selective hydrogen fluoride solvolysis followed by modification of the trisaccharides obtained and analysis of the ¹³C nuclear magnetic resonance spectra at each modification stage. The polysaccharides possessed similar structures of repeating units differing from each other in the anomeric configuration of the N‐acetylfucosamine residue only:→4)DManImU(β1→4)LGul(NAc)₂U(α1→3)DFucNAc(β1‐ and →4)DManImU(β1→4)LGul(NAc)₂U(α1→3)DFucNAc(α1‐,where DManImU = 2,3‐(1‐acetyl‐2‐methyl‐2‐imidazolino‐5,4)‐2,3‐dideoxy‐d‐mannuronic acid, LGul(NAc)₂U = 2,3‐diacetamido‐2,3‐dideoxy‐l‐guluronic acid, DFucNAc = 2‐acetamido‐2,6‐dideoxy‐d‐galactose. The same components were detected in the O:3(a),d,f polysaccharide but not in the same stoichiometric ratio; this polysaccharide possessed no regular structure. The immunochemical study of lipopolysaccharides of all five P. aeruginosa O:3 serotypes showed a definite interrelation between their serological properties and structures of the corresponding O‐specific polysaccharides.