Studies on Vi Antigen. I. Relative Vi Antigen Content of V Form Cultures

Abstract

The known V form non-typhoid organisms, Escherichia coli, P. [Salmonella] ballerup and Salmonella paratyphi C in the form of acetone dried organisms or HC1 extracts are all effective in the immunization of mice against typhoid challenge. Their relative potencies in this respect, compared with an arbitrarily fixed value of 1 for acetone dried S. typhosa Ty2 are as follows: E. coli, 6; P. ballerup, 3; S. paratyphi C. 0.02. It thus appears that E. colt 5396/38 is the richest source of Vi antigen among the known V form Enterobacteriaceae.