An Immunochemical Analysis of Bacterial Mucopeptides

Mucopeptides extracted from gram-positive and gram-negative bacteria which were solubilized by ultrasonic treatment gave precipitin reactions with rabbit antistreptococcal serum. A haptenic inhibitor isolated from S. albus enzymes digest of Group D streptococcal cell walls inhibited this precipitin reaction between the mucopeptides of heterologous bacteria and streptococcal antiserum. Greater than 87% inhibition of the M. lysodeikticus and 65% inhibition of the E. coli quantitative mucopeptide precipitin reactions was achieved with 4 mg/ml of this inhibitor. In double diffusion studies, the mucopeptides from different species of bacteria and streptococcal mucopeptide antiserum formed merging precipitin lines. These results suggest that the mucopeptides of many different species of bacteria possess antigenic determinants which are immunochemically similar to those of streptococci.