Production and characterization of antibodies against each of the three subunits of the Bacillus cereus nonhemolytic enterotoxin complex.
The nonhemolytic enterotoxin (Nhe) is one of the two three-component enterotoxins which are responsible for diarrheal food poisoning syndrome caused by Bacillus cereus. To facilitate the detection of this toxin, consisting of the subunits NheA, NheB, and NheC, a complete set of high-affinity antibodies against each of the three components was established and characterized. A rabbit antiserum specific for the C-terminal part (15 amino acids) of NheC was produced using a respective synthetic peptide coupled to a protein carrier for immunization. Using purified B. cereus exoprotein preparations as immunogens, one monoclonal antibody against NheA and several antibodies against NheB were obtained. No cross-reactivity with other proteins produced by different strains of B. cereus was observed. Antibodies against the NheB component were able to neutralize the cytotoxic activity (up to 98%) of Nhe. Based on indirect enzyme immunoassays, the antibodies developed in this study were successfully used in the characterization of the enterotoxic activity of several B. cereus strains. For the first time, it could be shown that strains carrying the nhe genes usually express the complete set of the three components, including NheC. However, the amount of toxin produced varies considerably between the different strains.
Dietrich
Richard
R
Institut für Hygiene und Technologie der Lebensmittel tierischen Ursprungs, Tierärztliche Fakultät, Universität München, Schönleutnerstrasse 8, 85764 Oberschleissheim, Germany. r.dietrich@mh.vetmed.uni-muenchen.de
Moravek
Maximilian
M
Bürk
Christine
C
Granum
Per Einar
PE
Märtlbauer
Erwin
E
D000595:Amino Acid Sequence; D000818:Animals; D000907:Antibodies, Bacterial; D000917:Antibody Formation; D001409:Bacillus cereus / Q000276:immunology*; D001483:Base Sequence; D017931:DNA Primers; D004768:Enterotoxins / Q000276:immunology*; D051379:Mice; D023421:Models, Animal; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction
D000907:Antibodies, Bacterial; D017931:DNA Primers; D004768:Enterotoxins; C040792:enterotoxin, Bacillus cereus