[The isolation and characterization of type 1 pili from pathogenic Escherichia coli of chicken origin]

The pili from pathogenic Escherichia coli isolates 566, 1794 and TK3 of chicken and turkey origin were purified. After mechanic detachment from the bacterial cells, the pili were concentrated by precipitation with ammonium sulfate, dialyzed, and solubilized in buffer containing deoxycholate. The fraction containing the pilus was purified further by ultracentrifugation in a sucrose gradient. After ultracentrifugation, the pili at the density of 1.10 to 1.15 g.cm-3 (between 10%-20% of sucrose gradients) were collected, and the purified pili from strain 566, 1794 and TK3 had an apparent molecular weight of 17,500, 17,000 and 17,000 respectively, which retained their ability to bind the erythrocyte in a mannose-inhibitable fashion. Hyperimmunesera raised in BALB/C mice against the purified pili from strain 1794 reacted positively with type 1 pili from both isolates 566 and TK3 by immuno blot. These results revealed that the three strains either Chinese or north american isolates expressed type 1 pili which had molecular weights from 17,000 to 17,500, and they have common antigenic epitopes.