Characterisation of cytolethal distending toxin (CDT) mutants of Campylobacter jejuni

In order to assess the contribution of cytolethal distending toxin (CDT) to the toxigenicity and pathogenicity of Campylobacter jejuni, the C. jejuni 81-176 and C. jejuni NCTC 11168 CDTs were inactivated by insertional mutati on of the cdtB toxin subunit, Cell-free sonicates from isogenic C, jejuni 8 1-176 cdtB(-) strains were found to be greatly attenuated in HeLa cytotoxic ity assays, whilst still retaining some toxigenicity, Sonicates from a C, j ejuni NCTC 11168 cdtB(-) strain produced no detectable cytotoxicity When or ally administered to adult severe combined immunodeficient (SCID) mice, C. jejuni cdtB mutant strains were unaffected in enteric colonisation abilitie s but demonstrated impaired invasiveness into blood, spleen and liver tissu es. These data suggest that CDT may be the principal toxin produced by this species and that some C. jejuni strains may generate additional toxigenic factor(s) distinct from CDT.