Lipoteichoic acid from Listeria monocytogenes

Abstract

A lipoteichoic acid (LTA) was extracted from L. monocytogenes (serotype I) by phenol-water partition and isolated by gel-filtration chromatography. The LTA exhibited amphiphilic properties by changes in gel-filtration mobility in the presence of detergent buffers and after mild base hydrolysis. In a hemagglutination assay, Listeria LTA bound antibody prepared against a known LTA from Streptococcus spp. Listeria LTA inhibited the binding of anti-LTA antibody to a Lactobacillus LTA in a hemagglutination inhibition assay. The Listeria LTA contained glucose, galactose, fatty acids, glycerol and phosphate with molar ratios of 0.05, 0.07, 0.21, 0.94 and 1.0 to phosphate, respectively. Adjacent glycerols were linked between the C-1 and C-3 positions by phosphodiesters (structural type 1). The average chain length was 19 .+-. 2 (SD) glycerol-phosphate repeating units. Approximately 1 glycosyl side chain was present per LTA molecule. The side chain was a galactose-containing disaccharide. The lipid portion of the LTA was a galactose- and glucose-containing glycolipid which may have been a phosphoglycolipid, but the structure was not confirmed. Major fatty acids of LTA and the glycolipid were 17:anteiso 15:anteiso, 16:iso, 16:n and 18:n. L. monocytogenes contained cell wall products typical of gram-positive bacteria in contrast to reports of the presence of lipopolysaccharides in L. monocytogenes.