Immunological relations of proteins from four salmonellae sharing an "O" factor 8.

The proteins from S. virginia, with the sole 8 "O" factor, precipitated against homologous and related heterologous sera by a conspicuous, homogenous line of serological identity, with proteins from: S. newport (6.8), S. blockley (6.8), S. emek (8.20). The proteins, however, were not involved in the bacterial agglutinations since the absorptions, which removed the common precipitins from the sera, did not modify the homologous agglutinations. The results with anti-S. newport and anti-S. blockley sera sharing identical "O" factors while displaying different immunochemical compositions as well as the strong immunochemical relations found between S. virginia and S. newport belonging to the different subgroups C2 and C3 underline the non-relatedness of agglutinins and precipitins.