Growth Inhibition of Escherichia coli 987P by Neutralizing IgY Antibodies

Hoon H. Sunwoo*, Eun N. Lee, Naiyana Gujral, Mavanur R. Suresh
1 Oregon Health & Science University, School of Nursing, 3455 SW US Veterans Hospital Road, Portland, OR 97239, USA
2 Oregon Health & Science University Cancer Institute, Division of Hematology and Medical Oncology, 3181 SW Sam Jackson Park Rd., Portland, OR 97239, USA
3 Oregon Health & Science University, School of Medicine, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA

© Sunwoo et al.;

open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

* Address correspondence to this author at the Faculty of Pharmacy and Pharmaceutical Sciences, University of Alberta, 114 St - 89 Ave, Edmonton, Alberta T6G 2N8, Canada; Tel: 780-492-0547; Fax: 780-492-1217; E-mail:


Egg yolk antibodies, called IgY, were isolated from the egg yolks of chickens immunized with enterotoxigenic Escherichia coli (ETEC) 987P. Specific binding activity of IgY against ETEC 987P was found. Whole cell titers remained relatively high during the immunization period (up to 19 weeks). The IgY antibodies cross-reacted with other members of Enterobacteriaceae, Escherichia coli O157:H7, Salmonella enteritidis, and S. typhimurium by 28.3%, 21.1% and 19.7%, respectively. Specific IgY with a concentration higher than 0.54 mg/ml was found to inhibit the growth of ETEC 987P in a liquid medium. The difference in bacterial growth between the specific and the non-specific IgY was 6.1 log CFU/ml after 8 hr incubation. The specific binding activity of IgY to bacteria was further evaluated by immunofluorescence and immunoelectron microscopy, showing the binding of specific IgY to the bacterial surface. The immunoelectron microscopic observation revealed structural alterations on the bacterial surface bound by specific IgY. This proves that specific binding activity of IgY against ETEC 987P whole cells resulted in growth inhibition of effect ETEC 987P in vitro.

Keywords: Egg Yolk Antibody (IgY), Escherichia Coli987P, Specific Binding Activity, Growth Inhibition, Immunofluorescence, Immunoelectron Microscopy.