EDWARDSIELLA-TARDA INDUCES PLASMA-MEMBRANE RUFFLES ON INFECTION OF HEP-2 CELLS

Interaction of two clinical Edwardsiella tarda isolates with HEp-2 cel ls was investigated. By electron microscopy we observed at 1 h post in fection that E. tarda induced formation of extensive plasma membrane p rojections resembling membrane ruffles. The ruffles did not coincide w ith adhering bacteria. Only few invading bacteria were seen. Vacuolate d nuclear membrane was occasionally observed. Three hours post infecti on, E. tarda induced a contact-dependent cell lysis, revealing the hos t cell cytoskeleton and nucleus. Only one of the E. tarda strains was seen residing within the host cell remains. The results indicate that E. tarda-induced membrane ruffles may involve a distinct mechanism of bacterial pathogenesis. (C) 1998 Published by Elsevier Science B.V.