Distribution of Receptor Glycolipids for Lactobacilli in Murine Digestive Tract and Production of Antibodies Cross-reactive with them by Immunization of Rabbits with Lactobacilli

In the digestive tract of mice (HR-1 strain), glycolipids belonging to the ganglio-series were revealed to be expressed in region-specific manners, i.e. FGA1 and FGM1 in the stomach, GA1 in the small intestine, and FGA1 and sulphatides in the cecum. The amount of GA1 as a receptor glycolipid for Lactobacilli was especially higher in the small intestine than in the other regions, it comprising 1.6-2.8 μg/mg dry weight. On immunization of rabbits with Lactobacillus johnsonii and Lactobacillus intestinalis, both of which are murine intestinal bacteria, antibodies toward bacterial glycolipids, i.e. Galα1-2Glcα1-3DG, and tri- and tetrahexaosyl DGs, were effectively generated and, in addition, they were found to cross-react with GA1 and GalCer, but not with structurally related glycolipids such as Lc 4 Cer, nLc 4 Cer and IV 3 Galα-nLc 4 Cer, indicating that GA1 is a preferable antigen for anti-lactobacillus antisera and suggesting the presence of epitopes common to both Lactobacilli and the host. In fact, molecules reacting with anti-GA1 antibodies were detected among bacterial proteins on Western blotting, indicating a possible occurrence of the carbohydrate structure mimicking GA1 in bacterial proteins.