Campylobacter jejuni and Campylobacter coli Production of a Cytotonic Toxin Immunologically Similar to Cholera Toxin

Abstract

An enzyme-linked immunosorbent assay (ELISA) based on binding to cholera toxin (CT) antibody was used to screen cell-free supernatant fluids from 11 strains of Campylobacter jejuni and one strain of Campylobacter coli. Positive results for seven of the eight clinical isolates as well as for one animal and one food isolate suggested that these strains produced an extracellular factor immunologically similar to CT. An affinity column (packed with Sepharose 4B conjugated to purified anti-CT IgG via cyanogen bromide) was used to separate the extracellular factor from cell-free supernatant fluids. Both unconcentrated supernatant fluids and affinity-purified material caused rounding in a Y-1 mouse adrenal cell assay, suggesting that the factor was a cytotonic toxin. Rounding of Y-1 cells caused by cell-free supernatant fluids, affinity-purified toxin or CT was neutralized by preincubation with CT or Campylobacter cytotonic toxin (CCT) antiserum. CCT and CT showed a reaction of partial identity by gel immunodiffusion, using IgG from CT antiserum. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS PAGE) of purified CCT produced one band at 70,000 daltons. Cell-free concentrates were positive in the rabbit skin permeability test and caused fluid accumulation in rabbit ileal loops. However, cell-free supernatant fluids and concentrates heated at 90°C for 15 min and tested by the suckling mouse assay produced no fluid accumulation in the intestines of mice.