REPRESSION OF MOTILITY AND FLAGELLIN PRODUCTION AT 37-DEGREES-C IS STRONGER IN LISTERIA-MONOCYTOGENES THAN IN THE NONPATHOGENIC SPECIES LISTERIA-INNOCUA

Listeria monocytogenes and Listeria innocua differ markedly in virulen ce but are indistinguishable by classical taxonomic criteria. Both spe cies are actively motile and produce abundant flagellin at 22 degrees C. We have found, however, noticeable differences between L. monocytog enes and L. innocua in motility and flagellin production at 37 degrees C. At this temperature, L. monocytogenes strains were virtually nonmo tile and produced little or no detectable flagellin, whereas strains o f L. innocua were frequently motile and produced substantial amounts o f flagellin. This flagellin was recognized by a Listeria genus-specifi c monoclonal antibody that also recognized flagellin produced at 22 de grees C. These results suggest differential regulation of flagellin pr oduction between L, monocytogenes and L. innocua at 37 degrees C.