Decreased adherence of enterohemorrhagic Escherichia coli to HEp-2 cells in the presence of antibodies that recognize the C-terminal region of intimin.
Antiserum raised against intimin from enterohemorrhagic Escherichia coli (EHEC) O157:H7 strain 86-24 has been shown previously by our laboratory to inhibit adherence of this strain to HEp-2 cells. In the present study, we sought to identify the region(s) of intimin important for the effect of anti-intimin antisera on EHEC adherence and to determine whether antisera raised against intimin from an O157:H7 strain could reduce adherence of other strains. Compared to preimmune serum controls, polyclonal sera raised against the histidine-tagged intimin protein RIHisEae (intimin(O157)) or against His-tagged C-terminal fragments of intimin from strain 86-24 reduced adherence of this strain. Furthermore, an antibody fraction purified from the anti-RIHisEae serum that contained antibodies to the C-terminal third of intimin, the putative receptor-binding domain, also reduced adherence of strain 86-24, but a purified fraction containing antibodies to the N-terminal two-thirds of intimin did not inhibit adherence. The polyclonal anti-intimin(O157) serum raised against RIHisEae inhibited, to different degrees, the adherence of another O157:H7 strain, an EHEC O55:H7 strain, one of two independent EHEC O111:NM isolates tested, and one of two EHEC O26:H11 strains tested. Adherence of the other O26:H11 and O111:NM strains and an EPEC O127:H6 strain was not reduced. Finally, immunoblot analysis indicated a correlation between the antigenic divergence in the C-terminal third of intimins from different strains and the capacity of anti-intimin(O157) antiserum to reduce adherence of heterologous strains. Taken together, these data suggest that intimin(O157) could be used as an immunogen to elicit adherence-blocking antibodies against O157:H7 strains and closely-related EHEC.
Gansheroff
L J
LJ
Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, Maryland 20814-4799, USA.
Wachtel
M R
MR
O'Brien
A D
AD
D018829:Adhesins, Bacterial; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology*; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D002352:Carrier Proteins; D003429:Cross Reactions; D004926:Escherichia coli / Q000276:immunology / Q000472:pathogenicity*; D019453:Escherichia coli O157 / Q000276:immunology / Q000472:pathogenicity*; D029968:Escherichia coli Proteins; D006801:Humans; D015151:Immunoblotting; D014407:Tumor Cells, Cultured
D018829:Adhesins, Bacterial; D000907:Antibodies, Bacterial; D001425:Bacterial Outer Membrane Proteins; D002352:Carrier Proteins; D029968:Escherichia coli Proteins; C073819:eaeA protein, E coli