Common and Unique Gene Expression of Avian Macrophages in Response to Three Major Eimeria Species
Rami A. Dalloul,1,* Hyun S. Lillehoj1,# Travis W.
Bliss,2 Yeong-Ho Hong1 and Calvin L. Keeler2
1Animal Parasitic Diseases Laboratory, Animal and Natural Resources Institute,
USDA-ARS, Beltsville, MD 20705, USA
2Department of Animal and Food Sciences, College of Agriculture and Natural
Resources, University of Delaware, Newark, DE 19716, USA
ABSTRACT
Host immune responses to Eimeria are very complex and involve both innate and
adaptive immunities. The chicken intestine is an intricate and dynamic ecosystem
where immune elements interact with antigenic components of pathogens as well as
with those of nutrients, exogenous compounds and microflora. These immune
responses are also influenced by the host genetic makeup and their interactions
are essential in the defense against enteric pathogens like Eimeria. The
outcomes of these complex interactions determine resistance to infection, and
the development of genomic tools and techniques allows for analysis of such
multiple and complex host responses. Macrophages and intraepithelial lymphocytes
(IELs) are critical components of the intestinal immune system and have been
shown to play significant roles in both the innate and acquired immune responses
to Eimeria. In order to better understand the immunobiology of host-parasite
interaction, avian macrophage and IEL cDNA microarrays were used. Using avian
macrophage microarray containing 4,906 unique gene elements obtained from
chicken macrophage cDNA library and spotted in triplicates, we identified
important host genes which expression were enhanced following infection of
macrophages with sporozoites of E. tenella, E. acervulina, and E. maxima. Genes
which showed significant expression were confirmed using real-time quantitative
PCR. Host genes, which expression changed significantly after infection with
Eimeria, included many genes encoding cytokines and chemokines that are
associated with inflammatory responses. Among key cytokine genes that increased
shortly after infection IFN-g, IL-2, IL-15, IL-16 IL-17, and IL-18 were included.
Furthermore, we prepared a cDNA library from intestinal IELs of Eimeria-infected
chickens and constructed a small intestinal microarray containing over 10,000
unique elements spotted in duplicates. Investigations are currently under way to
study kinetic gene expression in mucosal scrapings of birds infected by one of
the three Eimeria species. Further analysis of these expression patterns will
contribute to a better understanding of the mechanisms underlying resistance and
susceptibility to coccidiosis.
*Presenting author
#Corresponding author: hlilleho@anri.barc.usda.gov