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Updated: May 24, 2026
Foodborne Pathogen Screening Using Magneto-fluorescent Nanosensor: Rapid Detection of E. Coli O157:H7
Published on: September 17, 2017
A rapid subtractive immunization method to prepare discriminatory monoclonal antibodies for food E. coli O157:H7
Min Jin1, Jing Lang, Zhi-Qiang Shen
1Department of Environment and Health, Institute of Health and Environmental Medicine, Key Laboratory of Risk Assessment and Control for Environment and Food Safety, Tianjin, China.
To detect food E. coli O157:H7 contamination rapidly and accurately, it is essential to prepare high specific monoclonal antibodies (mAbs) against the pathogen. Cyclophosphamide (Cy)-mediated subtractive immunization strategy was performed in mice to generate mAbs that react with E. coli O157:H7, but not with other affiliated bacteria. Specificity of 19 mAbs was evaluated by ELISA and/or dot-immunogold filtration assay (DIGFA). Immunogloubin typing, affinity and binding antigens of 5 selected mAbs were also analysed. MAbs 1D8, 4A7, 5A2 were found to have high reactivity with E. coli O157:H7 and no cross-reactivity with 80 other strains of bacteria including Salmonella sp., Shigella sp., Proteus sp., Yersinia enterocolitica, Staphylococcus aureus, Klebsiella pneumoniae, Citrobacter freundii and other non-E. coli O157:H7 enteric bacteria. Their ascetic titers reached 1:10(6) with E. coli O157:H7 and affinity constants ranged from 1.57 × 10(10) to 2.79 × 10(10) L/mol. The antigens recognized by them were different localized proteins. Furthermore, immune-colloidal gold probe coated with mAb 5A2 could specifically distinguish minced beef contaminated by E. coli O157:H7 from 84 other bacterial contaminations. The Cy-mediated subtractive immunization procedure coupled with hybridoma technology is a rapid and efficient approach to prepare discriminatory mAbs for detection of E. coli O157:H7 contamination in food.
To detect food E. coli O157:H7 contamination rapidly and accurately, it is essential to prepare high specific monoclonal antibodies (mAbs) against the pathogen. Cyclophosphamide (Cy)-mediated subtractive immunization strategy was performed in mice to generate mAbs that react with E. coli O157:H7, but not with other affiliated bacteria. Specificity of 19 mAbs was evaluated by ELISA and/or dot-immunogold filtration assay (DIGFA). Immunogloubin typing, affinity and binding antigens of 5 selected mAbs were also analysed. MAbs 1D8, 4A7, 5A2 were found to have high reactivity with E. coli O157:H7 and no cross-reactivity with 80 other strains of bacteria including Salmonella sp., Shigella sp., Proteus sp., Yersinia enterocolitica, Staphylococcus aureus, Klebsiella pneumoniae, Citrobacter freundii and other non-E. coli O157:H7 enteric bacteria. Their ascetic titers reached 1:10(6) with E. coli O157:H7 and affinity constants ranged from 1.57 × 10(10) to 2.79 × 10(10) L/mol. The antigens recognized by them were different localized proteins. Furthermore, immune-colloidal gold probe coated with mAb 5A2 could specifically distinguish minced beef contaminated by E. coli O157:H7 from 84 other bacterial contaminations. The Cy-mediated subtractive immunization procedure coupled with hybridoma technology is a rapid and efficient approach to prepare discriminatory mAbs for detection of E. coli O157:H7 contamination in food.
