Protective Immune Responses Induced in Chickens by Outer Membrane Proteins Extracted from Different Strains of Escherichia coli.

Different strains of Escherichia coli (E. coli) from human, chickens, and the common strain between human and chickens were isolated and typed with mono-specific antibody. The E. coli strains from each group of human, chicken and common between human and chicken were selected. The polypeptide patterns of selected strains were analyzed and compared with each other by Sodium dodecyle sulphate polyacrylamide gel electrophoresis (SDS - PAGE). The SDS - polyacrylamide gel electrophoresis patterns between the strains were very similar, although the densities of some of the peptide bands were different, and some were missing in some strains. A similar comparison was made on extracted outer membrane proteins (OMP) using Triton X-100 and sodium dodecyle sulphate on the above-mentioned strains. The polypeptide patterns between the strains 078 (chicken strain), 06 (human strain) and O2 (the common strain between human and chicken) were also very similar and two major bands with molecular weights of 44 KD and 25 KD were very distinctive, and seen between all the strains.The passive haemoagglutination tests (PHA) in chickens injected OMP from the common strain (O2), showed increased level of antibody after the second injection which remained constant after repeated injections.In the challenge study, with LD100 from homologous strain of O2, a significant protection was observed in the groups injected the OMP (extracted from O2 strain), compared with controls injected saline.The results of this study indicate that purified E. coli outer membrane protein, can induce a significant protection immunity against colibacillus diseases in chickens, and probably in immunocompromised hosts with repeated urinary infections.