|KRASTINS, BRYAN - Thermo Fisher Scientific|
|TORRES, ALFREDO - University Of Texas Medical Branch|
|GRIFFIN, ROBERT - Massachusetts General Hospital|
|SHENG, HAIQING - University Of Idaho|
|SARRACINO, DAVID - Thermo Fisher Scientific|
|HOVDE, CAROLYN - University Of Idaho|
|CALDERWOOD, STEPHEN - Massachusetts General Hospital|
|JOHN, MANOHAR - Pathovacs, Inc|
Submitted to: Proteomics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/20/2015
Publication Date: 1/23/2015
Citation: Kudva, I.T., Krastins, B., Torres, A., Griffin, R.W., Sheng, H., Sarracino, D.A., Hovde, C.J., Calderwood, S.B., John, M. 2015. The Escherichia coli O157:H7 cattle immunoproteome includes outer membrane protein A (OmpA), a modulator of adherence to bovine rectoanal junction squamous epithelial (RSE) cells. Proteomics. 15:1829-1842.
Interpretive Summary: Cattle are the primary source of Escherichia coli (E. coli) O157, a bacterium (micro-organism) responsible for bloody diarrhea and other serious symptoms in humans that can even lead to death. Although E. coli O157 can cause serious disease in humans, cattle carry this bacterium in their intestines without getting any disease and shed this bacterium in their feces. When carrying the bacterium, the animal's immune system (system that combats infections) recognizes some of the proteins produced by E. coli O157 and develops antibodies to them. However, the antibody response is not strong enough to remove E. coli O157 from the cattle gastrointestinal tract (GIT). The objective of this study was to identify the E. coli O157 proteins being targeted by the cattle antibodies, and use this information to develop strategies to increase the strength of the antibody response to eliminate E. coli O157 from the cattle GIT. Another objective of this study, was to identify protein targets of bovine antibodies produced by the bacterium in the cattle intestines for binding bovine rectal cells. Such proteins are important in that they are the basis for development of new anti-adherence/binding therapies to prevent E. coli O157 from sticking to the GIT and surviving in cattle.
Technical Abstract: Building on previous studies, we defined the repertoire of proteins comprising the antigenome of Escherichia coli (E. coli) O157 cultured in Dulbecco's Modified Eagles Medium (DMEM) supplemented with norepinephrine (NE; O157 protein-antigenome), a beta-adrenergic hormone that regulates E. coli O157 gene expression in gastrointestinal tracts, using a variation of a novel proteomics-based platform proteome mining tool for antigen discovery, called Proteomics-based Expression Library Screening (PELS; Kudva et al., 2006). The E. coli O157 protein-antigenome (O157-PA) comprised 91 proteins, and included those identified previously using PELS, and also proteins comprising DMEM- and bovine rumen fluid- proteomes. Outer membrane protein A (OmpA), a common component of the above proteomes, and reportedly a contributor to E. coli O157 adherence to cultured Hep-2 epithelial cells, was interestingly found to be a modulator rather than a contributor to E. coli O157 adherence to bovine recto-anal junction squamous epithelial (RSE) cells. Our results point to a role for yet to be identified members of the O157-PA in E. coli O157 adherence to RSE-cells, and additionally allude to a possible role for the OmpA regulator, TdcA, in the expression of such adhesins. Our observations have implications for development of efficacious vaccines for preventing O157 colonization of the bovine gastrointestinal tract.