Open AccessEnterotoxicity and immunological properties of two mutant forms of Escherichia coli STIp with lysine or arginine substituted for the asparagine residue at position 11.
Author(s) -
Keinosuke Okamoto,
Jun Yukitake,
Kazushi Okamoto,
Akio Miyama
Publication year - 1992
Publication title -
pubmed
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
ISSN - 0378-1097
DOI - 10.1016/0378-1097(92)90154-g
Subject(s) - enterotoxin , heat stable enterotoxin , escherichia coli , heat labile enterotoxin , arginine , mutant , asparagine , chemistry , biochemistry , biology , microbiology and biotechnology , amino acid , gene
Two variants of Escherichia coli heat-stable enterotoxin Ip, in which the amino acid residue at position 11 was substituted with lysine or arginine, were purified to near homogeneity from the culture supernatants of toxin-producing mutant strains. Neither the purified heat-stable enterotoxin Ip(Lys-11) nor the purified heat-stable enterotoxin Ip(Arg-11) showed a positive response in the suckling mouse assay or in the mouse intestinal loop assay. Furthermore, live bacteria producing these mutant heat-stable Ip enterotoxins did not cause fluid accumulation in mouse intestinal loops, in contrast to bacteria producing native heat-stable enterotoxin Ip. Nevertheless, antisera raised against both heat-stable enterotoxin Ip(Lys-11) and heat-stable enterotoxin Ip(Arg-11) neutralized the enterotoxic activity of native heat-stable enterotoxin Ip. These results demonstrate that heat-stable enterotoxin Ip(Lys-11) and heat-stable enterotoxin Ip(Arg-11) lose enterotoxicity but retain epitopes which are common to native heat-stable enterotoxin Ip.