Abstract: | An antigenic determinant isolated from a strain of the Gram-negative bacterium Butyrivibrio fibrisolvens reacted with specific antisera to the polyglycerophosphate backbone of membrane teichoic acids of lactobacilli. It gave a reaction of identity with membrane glycerol lipoteichoic acid and glycerol teichoic acid preparations from lactobacilli, and with phenol extracts of other Gram-positive bacteria. The antigen-antibody reactions was strongly inhibited by glycerol-phosphoryl-glycerol-phosphoryl-glycerol and the chemical composition was consistent with glycerol teichoic acid. It was concluded that this Gram-negative bacterium contained a glycerol teichoic acid whose polyglycerophospate backbone was acting as antigenic determinant. Extracts of 33 out of 52 other strains of butyrivibrios examined gave similar reactions. |