1a.Objectives (from AD-416):
To explore the possibility of initial stage of host gene manipulation by developing RNA interference technology using primary lymphocytes. We will use RNAi technology to modulate IFN-y response since IFN-y is a key immunoregulatory cytokine of macrophages for mucosal immune response.
1b.Approach (from AD-416):
Peripheral blood monocytes will be cultured in vitro and treated with siRNA using recently developed RNA interference (RNAi) technology to knockdown/silence post-transcriptional gene expression of chicken IFN-y.
During this reporting period, changes in the expression levels of avian beta-defensin (AvBD) messenger RNA were evaluated in necrotic enteritis (NE) disease model in two genetically disparate commercial broiler chicken lines (designated R and C). NE was initiated in the gut by a previously established co-infection model using oral Eimeria maxima infection followed by Clostridium perfringens challenge. There was a tissue-specific expression of AvBD transcripts with many of them showing strong expression in the gut. Two different commercial broiler chicken lines showed differential gene expression patterns of AvBD transcripts following NE infection, with R line chickens generally showing higher expression levels than C line. Both chicken strains showed enhanced gene expression levels of pro-inflammatory cytokines such as interleukin (IL)-1 beta and IL-6 in the intestine. Although the exact nature of interactions between defensins and cytokines in determining the outcome of host innate immune responses to the pathogens of NE remains to be investigated, the differences in gene expression levels of innate immune genes in the intestine could explain the genetically determined disease resistance and susceptibility to NE in commercial chickens.