Ascertainment of the presence in enterobacteriaceae of mixtures of proteins with salmonellae and E. coli specificities.

Comparative agar-gel diffusions of sera to proteins from E. coli O 126 and from S. enteritidis and samples of the sera absorbed with heterologous proteins proved that all were mixtures of antigens with specificities of common Salmonellae and E. coli. The absorption of the E. coli serum with proteins from S. typhi removed the smallest amont of antibodies while absorption with proteins from S. enteritidis removed common antibodies resembling those eliminated by absorption with heterologous E. coli proteins. Similar results were obtained by the opposite absorption of the S. enteritidis serum with the E. coli O 126 proteins; it is apparent from the results that S. enteritidis and E. coli have in their composition mixtures of strongly related proteins sharing determinants for both species. An added confirmation of these findings was obtained by absorbing the E. coli serum with proteins from S. paratyphi A; the absorption removed antibodies induced against proteins from numerous E. coli and Salmonellae strains. A determinant common to all the E. coli and Salmonellae - that is apparently situated on the E. coli coli proteins - is still reacting by a thin precipitation line against all the antigens and is evident in all the E. coli absorbed sera.