Monoclonal antibodies binding to the cell surface of Listeria monocytogenes serotype 4b.
Serotype 4b strains of the food-borne pathogen Listeria monocytogenes are responsible for a large portion of sporadic listeric infections and all major food-borne listeriosis outbreaks in humans. Hybridomas were produced from three fusions with lymphocytes of ND4 mice immunized either with the insoluble antigens of L. monocytogenes serotype 4b or with formalin-killed bacterial cells and screened for monoclonal antibodies (mAbs) reactive to L. monocytogenes serotype 4b. A set of 35 mAbs was identified by ELISA as having reactivity with both the insoluble antigen fraction and the whole-cell antigens. Thirteen of these mAbs belonged to immunoglobulin subclass G1 (IgG1), fifteen were IgG2a and seven mAbs were IgM. Only 20 out of the 35 mAbs were capable of detecting protein bands of various sizes ranging from 20 to 88 kDa in Western blots. Two of these mAbs, M2365 and M2367, were capable of binding to cell-surface antigens of live L. monocytogenes serotype 4b, as demonstrated by immunofluorescence microscopy and immunogold transmission electron microscopy. Immunofluorescence microscopy showed that M2365 and M2367 failed to bind to the cell surfaces of Escherichia coli O157 : H7, Salmonella enterica (serotype Typhimurium DT104) or Campylobacter jejuni. Evaluation of the cross-reactions of all 35 mAbs with whole-cell antigens of E. coli O157 : H7, S. Typhimurium, C. jejuni and Listeria innocua by ELISA indicated that the majority of the mAbs, including M2365 and M2367, did not cross-react with E. coli O157 : H7, S. Typhimurium or C. jejuni and showed no or a very weak reaction with L. innocua. Furthermore, M2365 and M2367 showed no reaction with whole-cell antigens derived from L. monocytogenes serotypes 1/2a, 1/2b and 3a, and from Listeria grayi, Listeria ivanovii and Listeria seeligeri, in an ELISA. Collectively, these data suggest that M2365 and M2367 have potential use in the development of immunological methods of laboratory diagnosis for L. monocytogenes serotype 4b in clinical or food samples.
Lin
Min
M
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
Todoric
Dobrila
D
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
Mallory
Maria
M
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
Luo
B Steven
BS
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
Trottier
Erin
E
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
Dan
Hanhong
H
Animal Diseases Research Institute, Ottawa, Ontario, Canada K2H 8P9.
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology / Q000378:metabolism*; D000918:Antibody Specificity; D000942:Antigens, Bacterial / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D006825:Hybridomas; D007114:Immunization; D007132:Immunoglobulin Isotypes; D008089:Listeria monocytogenes / Q000145:classification* / Q000276:immunology* / Q000378:metabolism; D008088:Listeriosis / Q000175:diagnosis* / Q000276:immunology / Q000382:microbiology; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D012703:Serotyping
D000911:Antibodies, Monoclonal; D000942:Antigens, Bacterial; D007132:Immunoglobulin Isotypes; D008565:Membrane Proteins