Rapid Typing of Transmissible Spongiform Encephalopathy Strains with Differential ELISA
Stéphanie Simon*, Jérôme Nugier*, Nathalie Morel*, Hervé Boutal*, Christophe Créminon*, Sylvie L. Benestad†, Olivier Andréoletti‡, Frédéric Lantier§, Jean-Marc Bilheude¶, Muriel Feyssaguet¶, Anne-Gaëlle Biacabe#, Thierry Baron#, and Jacques Grassi*
Author affiliations: *Commissariat à l’Energie Atomique, Gif-sur-Yvette, France; †National Veterinary Institute, Oslo, Norway; ‡Institut National de la Recherche Agronomique-Ecole Nationale Vétérinaire de Toulouse, Toulouse, France; §Infectiologie Animale et Santé Publique, Tours, France; ¶Bio-Rad, Marnes-la-Coquette, France; #Agence Française de Sécurité Sanitaire des Aliments, Lyon, France;
Figure 6. Proteinase K (PK) sensitivity of Nor98 isolates in stringent and mild detergent conditions. The ELISA typing test was performed on Nor98 isolates, with 5 concentrations (0.4–1.1 µg per mg of tissue) in the stringent A′reagent (A) or in the mild A′′ reagent, adapted for PK-sensitive strains (B) (see Experimental Procedures). A/A′(or A/A′′) ratios were calculated for each PK concentration, and normalized by dividing by the A/A′ratio (or A/A′′) obtained for the experimental ovine bovine spongiform encephalopathy (BSE) sample at the maximal PK concentration. In the A’ reagent, even at the lowest PK concentration (PK 0.4 μg/mg tissue), the normalized ratios (using the experimental ovine BSE A/A′PK1.1 ratio) obtained for the Nor98 isolates are >1, thus being 3× more sensitive than experimental ovine BSE. To evaluate possible differences in PK sensitivity among Nor98 isolates, this experiment was reproduced with the A′′ reagent (panel B), which is 3- to 6-fold more protective than the A′reagent, as shown by the corresponding normalized ratios (A′or A′′ reagent) for the same PK concentration (1.1 μg PK/mg of tissue).
The opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.