Microarray Analysis of the Intestinal Host Response in Giardia duodenalis Assemblage E Infected Calves

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From: PLoS ONE(Vol. 7, Issue 7)
Publisher: Public Library of Science
Document Type: Article
Length: 6,060 words
Lexile Measure: 1460L

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Author(s): Leentje Dreesen 1 , Manuela Rinaldi 1 , Koen Chiers 2 , Robert Li 3 , Thomas Geurden 1 , Wim Van den Broeck 4 , Bruno Goddeeris 1 , Jozef Vercruysse 1 , Edwin Claerebout 1 , Peter Geldhof 1 , *

Introduction

The protozoan parasite Giardia duodenalis (also known as G. intestinalis and G. lamblia ) is one of the most commonly found intestinal pathogens in a wide range of vertebrate hosts. In humans, an estimated 280 million infections occur yearly, especially in developing countries. In addition, G. duodenalis is a common parasite in both farm and companion animals [1]. Several studies have shown that for cattle, sheep, and goats farm prevalences can be as high as 100% [2].

An infection with G. duodenalis can present itself with gastro-intestinal complaints such as diarrhea, although infections often remain asymptomatic and therefore unnoticed by the carrier. Younger individuals are especially at risk of developing clinical giardiasis, and chronic infections can lead to malnutrition, growth impairment, and, in the case of humans, poor cognitive development [3], [4], [5]. Both acute and chronic infections, whether symptomatic or not, have been described in earlier studies. In man, experimental infection with cysts led to spontaneous disappearance of cyst excretion in faeces after a period ranging from 5 to 41 days. In 2 persistent cases, cyst excretion lasted at least 129 days [6]. In longitudinal studies on children in Israel [7], Brazil [8] and Peru [9], infections were chronic with prolonged cyst excretion. In addition, infections were recurrent with reappearance of the parasite after treatment. In cattle, the general consensus is that infections are chronic and reoccuring as shown by cyst excretions lasting well over 100 days in both dairy and beef cattle [2]. Chronic infections are also documented in dogs [10], goats [11], and sheep [12].

Our knowledge of the immune response against G. duodenalis is largely based on in vitro studies and infection trials in mice with a human-derived axenised G. duodenalis assemblage B isolate or G. muris . Elements of the innate immune response, such as the production of nitric oxide, mucins, defensins, and other antimicrobial peptides, were shown to have a negative effect on trophozoites in vitro [13]. In the presence of live parasites and parasite extracts in vitro , murine bone marrow derived dendritic cells were inhibited in eliciting an LPS-induced Th1 inflammatory pathway due to decreased IL-12 and increased IL-10 production [14]. Further downstream, T-cell dependent mechanisms seem essential in the control of murine giardiasis, as shown by the development of chronic infections with G. duodenalis in nude mice, mice treated with anti-CD4, and mice lacking the T cell receptor [beta] gene [15]. In terms of cytokines, IL-6 was observed to be produced by DC's in the presence of live parasite and parasite extract [16]. Production of TNF-[alpha], IFN-[gamma], IL-4, IL-10, IL-13, IL-17 and IL-22 by mouse lymph node cells in response to parasite extract [17] is also described, while in humans elevated levels of IL-5, IL-6 and IFN-[gamma] were seen in...

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Gale Document Number: GALE|A498244887