Journal article
Intestinal Shiga Toxin-Producing Escherichia coli Bacteria Mitigate Bovine Leukemia Virus Infection in Experimentally Infected Sheep
Infection and immunity, Vol.74(5), pp.2906-2916
05/2006
Handle:
https://hdl.handle.net/2376/112365
PMCID: PMC1459712
PMID: 16622229
Abstract
Ruminants often carry gastrointestinal Shiga toxin (Stx)-producing
Escherichia coli
(STEC). Stxs belong to a large family of ribosome-inactivating proteins (RIPs), found in many plants and some bacteria. Plant RIPs, secreted into extracellular spaces, limit the spread of viruses through plant tissues by penetrating and killing virally infected cells. Previously, we showed Stx activity against bovine leukemia virus (BLV)-infected cells in vitro and hypothesized that STEC bacteria have antiviral activity in ruminant hosts. Here, we investigated the impact of STEC on the initial phases of BLV infection in sheep. Sheep were treated with biweekly oral doses of
E. coli
O157:H7 (an STEC) or an isogenic
stx
mutant strain. A different group of sheep were similarly treated with five naturally occurring ovine STEC isolates or
stx
-negative
E. coli
. Intestinal STEC bacteria were enumerated and identified by standard fecal culture and DNA hybridization. Oral STEC treatment did not always result in carriage of STEC, although many animals consistently presented with >10
4
CFU/g feces. BLV viremia was assessed by spontaneous lymphocyte proliferation (SLP) in cultures of blood mononuclear cells and by syncytium formation in cocultures of the same with F-81 indicator cells. SLP was lower (
P
< 0.05) and syncytia were fewer (
P
< 0.05) in STEC-treated sheep than in untreated sheep. Both lower SLP and fewer syncytia positively correlated with fecal STEC numbers. Average weight gain post-BLV challenge was higher in STEC-treated sheep than in untreated sheep (
P
< 0.05). These results support the hypothesis that in ruminants, intestinal STEC bacteria have antiviral activity and mitigate BLV-induced disease.
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Details
- Title
- Intestinal Shiga Toxin-Producing Escherichia coli Bacteria Mitigate Bovine Leukemia Virus Infection in Experimentally Infected Sheep
- Creators
- Witold A Ferens - Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052Rowland Cobbold - Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052Carolyn J Hovde - Department of Microbiology, Molecular Biology and Biochemistry, University of Idaho, Moscow, Idaho 83844-3052
- Publication Details
- Infection and immunity, Vol.74(5), pp.2906-2916
- Publisher
- American Society for Microbiology
- Identifiers
- 99900547995401842
- Language
- English
- Resource Type
- Journal article