Abstract :
Enteropathogenic Escherichia coli (EPEC) is a leading cause of diarrhea in newly born animals in
developing countries and could be transmitted to children and stressed adults as travelers through contaminated meat
and milk. Continuous trials were performed to prevent this disease using different antigenic determinants. This study
was conducted at three E. coli serotypes O78, O125, and O158, which were isolated from diarrheic calves, buffalo
calves and lambs in Egyptian farms, to extract periplasmic protein and lipopolysaccharide and assessed their
antigenic and diagnostic performance. SDS-PAGE electrophoresis was conducted on crude extracted periplasmic
proteins from the isolated serotypes O78, O125, and O158, and revealed 8,9, and 9 bands respectively, ranged from
43 to 257 kDa with sharing in 5 bands and the molecular profile nearly similar between the three serotypes. Native
SDS-PAGE silver stained electrophoresis was conducted on extracted crude lipolpolysaccharides and showed 10,7,
and 3 bands for serotypes O78, O125, and O158 respectively ranged from 25 to 168 kDa with sharing in 3 bands.
Agar gel immunodiffusion test was carried out on the extracted crude periplasmic proteins and lipopolysaccharides
from the three E.coli serotypes, against E.coli antisera previously prepared in rabbit, and the studied both antigens
gave precipitin lines suggesting that the shared fractions appeared in electrophoresis may responsible for the
production of antibodies and may be considered a tool of diagnosis and future vaccine.
Keyword :
Escherichia coli, periplasmic, lipopolysaccharide, electrophoresis, Agar agel immunodiffusion.