A Typhoid Variant and a New Serological Variation in the Salmonella Group

Abstract

Recently Almon and Stovall (1939) reported on two cultures of Salmonella typhi which lacked an O-antigen. The cultures were described in the following manner: Cross absorption tests showed that the missing antigen was not the one which E. typhosa shares with Salmonella schottmuelleri, but was one which is normally present in S. enteritidis. On the assumption that the somatic antigenic fractions of E. typhosa are limited in number to two (since there was no evidence to the contrary apparent from these studies), the component which was lacking was tentatively identified as antigen IX of the Kauffmann scheme of classification. When this publication arrived I was engaged on work connected with serological variation within the O-antigens and had demonstrated a variation involving antigen XII that corresponded in principle to the "I-variation" (i.e. "I-Formenwechsel") which I had previously described. These new discoveries, of which Almon and Stovall were ignorant, necessitated a fresh study of these typhoid cultures with due regard for the XII-variation. Variation in antigen I was summarized by Kauffmann (1940) as follows: The development of antigen I varies in most of the Salmonella strains possessing this antigen. By means of a strong 0-serum of Salmonella senftenberg and slide agglutination it is possible sometimes within the same strain to differentiate three forms which I should call the I+ + form, the I+ form, and the Id form. S. senftenberg and Salmonella niloese occur in the I+ + form only. Most of the other strains possessing antigen I contain both the I++ form and the Is 127