RIG-I Has a Role in Immunity Against Haemonchus contortus, a Gastrointestinal Parasite in Ovis aries: A Novel Report.

Retinoic acid inducible gene I (RIG-I) is associated to the DExD/H box RNA helicases. It is a pattern recognition receptor (PRR), playing a crucial role in the system and is a germ line encoded host sensor to perceive pathogen-associated molecular patterns (PAMPs). So far, reports are available for the role of RIG-I in antiviral immunity. This is the first report in which we have documented the role of RIG-I in parasitic immunity. Haemonchus contortus is a deadly parasite affecting the sheep industry, which has a tremendous economic importance, and the parasite is reported to be prevalent in the hot and humid agroclimatic region. We characterize the RIG-I gene in sheep (Ovis aries) and identify the important domains or binding sites with Haemonchus contortus through in silico studies. Differential mRNA expression analysis reveals upregulation of the RIG-I gene in the abomasum of infected sheep compared with that of healthy sheep, further confirming the findings. Thus, it is evident that, in infected sheep, expression of RIG-I is triggered for binding to more pathogens (Haemonchus contortus). Genetically similar studies with humans and other livestock species were conducted to reveal that sheep may be efficiently using a model organism for studying the role of RIG-I in antiparasitic immunity in humans.