Degradation of Cry1Ab protein from genetically modified maize in the bovine gastrointestinal tract

J Agric Food Chem. 2005 Mar 9;53(5):1453-6. doi: 10.1021/jf049222x.

Abstract

Immunoblotting assays using commercial antibodies were established to investigate the unexpected persistence of the immunoactive Cry1Ab protein in the bovine gastrointestinal tract (GIT) previously suggested by enzyme-linked immunosorbent assay (ELISA). Samples of two different feeding experiments in cattle were analyzed with both ELISA and immunoblotting methods. Whereas results obtained by ELISA suggested that the concentration of the Cry1Ab protein increased during the GIT passage, the immunoblotting assays revealed a significant degradation of the protein in the bovine GIT. Samples showing a positive signal in the ELISA consisted of fragmented Cry1Ab protein of approximately 17 and 34 kDa size. Two independent sets of gastrointestinal samples revealed the apparent discrepancy between the results obtained by ELISA and immunoblotting, suggesting that the antibody used in the ELISA reacts with fragmented yet immunoactive epitopes of the Cry1Ab protein. It was concluded that Cry1Ab protein is degraded during digestion in cattle. To avoid misinterpretation, samples tested positive for Cry1Ab protein by ELISA should be reassessed by another technique.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animal Feed*
  • Animals
  • Bacterial Proteins / analysis*
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism
  • Bacterial Toxins / analysis*
  • Bacterial Toxins / genetics
  • Bacterial Toxins / metabolism
  • Blotting, Western
  • Cattle / metabolism*
  • Endotoxins / analysis*
  • Endotoxins / genetics
  • Endotoxins / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Gastrointestinal Tract / metabolism*
  • Hemolysin Proteins
  • Peptide Fragments / analysis
  • Plants, Genetically Modified / chemistry*
  • Zea mays / chemistry
  • Zea mays / genetics*

Substances

  • Bacterial Proteins
  • Bacterial Toxins
  • Endotoxins
  • Hemolysin Proteins
  • Peptide Fragments
  • insecticidal crystal protein, Bacillus Thuringiensis