Animal-passage of campylobacter strains with iron-dextran enhances the expression of an outer membrane protein

The outer membrane proteins [OMP] of four C. jejuni/coli isolates have been identified by SDS - PAGE using Sarkosyl extraction of crude membranes. Sarkosyl insoluble fractions of four strains consistently contained a major OMP in the range of 43 k to 48 k, in addition to some minor proteins. SDS - PAGE profile of animal - passed virulence enhanced strains, when compared with the original isogenic strains when compared with the original isogenic strains, revealed the presence of a protein band migrating at 66 k to 68 k in addition to the characteristic major OMP band, suggesting a selective enhancement of this protein during animal passage in presence of iron - dextran. This shift in OMP expression was associated with enhanced virulence of C. jejuni for BALB/c mice. Immunobloting to analyse the antigens in OMP showed antigenicity to the major OMP. The role of the 68 k OMP in the pathogenesis of C jejuni for BALB/c mice remains to be studied

Potential pathogenic mechanisms of animal-passed virulence-enhanced strains of campylobacter jejuni/coli

In order to study the potential pathogenic mechanisms, live cultures, culture-filterates and Poly-myxin B released extracts from original and animal-passed strains of C jejuni/coli were compared by a neonatal mouse infection and in-vitro Vero-Cell cytotoxicity. The cell fractions from mouse-passed strains elaborated strong cytotonic and cytotoxic activity causing elongation, granular appearance and lysis of Vero-Cells. Only weak enterotoxie activity was associated with the original strains. Partial neutralization of the cytotonic activity by mono-clonal anticholera toxin [CT] suggested immunological relationship between the toxins which was also demonstrated by Ouchterlony immunodiffusion using polyclonal anti - CT serum. The in-vivo significance of CT like and other toxic materials produced by Campylobacter strains during animal-passage remains to be assessed